SPECIAL DENTAL PATHOLOGY A WORK ON SPECIAL DENTAL PATHOLOGY DEVOTED TO THE DISEASES AND TREATMENT OF THE Investing Tissues of the Teeth and THE Dental Pulp INCLUDING THE SEQUEL.E OF THE DEATH OF THE PULP; ALSO, SYSTEMIC EFFECTS OF MOUTH INFECTIONS, ORAL PROPHYLAXIS AND MOUTH HYGIENE 518 ILLUSTRATIONS BY G. V. BLACK, M.D., D.D.S., SC.D., LL.D. DEAN AND PROIESSOR OF OPERATIVE DENTISfRY, DENTAL PATHOLOGY AND BACTERIOLOJY NORTHWESTERN UNIVERSITY DENTAL SCHOOL 1915 MEDICO-DENTAL PUBLISHING COMPANY CHICAGO CLAUDIUS AvSH, SONS & COMPANY LONDON Entered, according to Act of Congress, in the year 1915, by G. V. Black, In the Office of the Librarian of Congress, Washington, D. C. Entered at Stationers' Hall, London, Eng. »HtSS or THE MCNRv O SMfPARO CO.. CHICAOC- 3^//^ /^/^ PREFACE THE writing of this book was begun five years ago, and its completion lias been delayed in order that I might carry out long lines of experimental work upon several subjects which needed further investigation. In the prosecution of the work, I have continually had the cooperation and advice of my sons, Dr. Carl E. Black, of Jack- sonville, Illinois, and Dr. Arthur D. Black, of Chicago, which has been a veiy efficient aid. My thanks are due the Research Institute of the National Dental Association for a five months' assignment of Dr. H. A. Potts, to assist me in carrying out investigations in my labora- tory. I am under obligation to Dr. Thomas L. Gilmer, Dr. E. S. Wiilard, Dr. William Bebb, Dr. F. D. Leach, Dr. H. A. Potts, Dr. F. B. Noyes, and Dr. E. A. Schniedwind for suggestions and assistance. A number of the members of the classes of 1914 and 1915 of Northwestern University Dental School have aided, par- ticularly in experiments in collecting deposits of salivary cal- culus and in testing the effects of various drugs upon the tissues. The preparation of the illustrations and the final copy has been almost wholly under the management of Dr. Arthur D. Black, who has been in close touch with me constantly in this work. At my request, he has also written the article on Exam- inations of the Mouth, and Dr. Carl E. Black has supplied a com- pilation of the principal events leading to the development of antiseptic and aseptic surgery. I am under special obligation to my daughter. Miss Clara Black, and to Mrs. Arthur D. Black, for valuable assistance in proofreading. To all of these I wish to express my thanks. G. V. BLACK. Chicago, April 12, 1915. TABLE OF CONTENTS. Note. — This table of coutents has been prepared for use as an outline by stu- dents or practitioners who desire to make a careful synopsis in connection with the study of the subjects presented. All headings, subheadings and paragraph headings in the book are given in proper order, and the relations of these are shown by the positions of the headings m this table. PAGE Preface iii Introduction 1 Investing Tissues of the Teeth — The CJingiv.?-:, Peridental Membrane, Cementum and Auveouar Process. Histology AND Physical Functions 7 Gums and Gingivae 7 The Fibrous Mat 8 Epithelium i 9 Blood 9 Sensation 9 Healing Powers 11 OiNGiv.^i: 11 Parts of the Cingivte 13 Body of the GingivjK 13 Groups of Fibers in Gingivas and Peridental Membrane. . . 14 The Free Gingivae Group li) The Trans-Septal Group 15 The Alveolar Crest Group 16 The Free Gingivae 16 The Septal Gingivte 17 Epithelium of the Gingivte 19 Epithelium of the Septal Gingiva? 20 The Hormone 21 Development of the (Jingivae 22 The Subgingival Spaces . 24 Exploration of the Subgingival Spaees 25 Functions of the (Jingiva' 26 A Protective Tissue 26 Maintenance of Teeth in the Line of the Arch 28 (vii) Vlll SPECIAL DENTAL PATHOLOGY. PAGE Cementum, Peridental Membrane and Alveolar Process 30 Histological Studies of the Peridental Membrane 30 Cementum 31 Differences between Cementum and Bone 32 Cementum does not Repair Injuries 32 Cementum Subject to Absorption 32 Absorption of Roots of Permanent Teeth 33 Attachment of Principal Fibers of the Peridental Membrane to the Cementum 34 Cementum Continuous Growing 34 ITypercementosis 35 Cementum in Animals 35 Peridental Membrane 36 Fibers of the Peridental Membrane 36 Horizontal Group 37 Obli(iue Group 37 Apical Group 39 Indefinite Connective Tissue 40 Blood Vessels 40 Nerves 40 Osteoblasts 41 Cementoblasts 42 Epithelium 43 Physical Powers of the Peridental Membrane and Cementum, AS Shown by Planted Teeth 45 Planting of Teeth 45 Replantation 46 Transplantation 46 Implantation 47 No Histo-Pathological Studies of Planted Teeth 47 Chemotaxis 48 Attachment of Planted Teeth Physiologically Unstable 49 Ai.veolar Process . .i 50 Alveolar Processes Are Bone 51 Development of the Alveolar Process 52 When the Teeth Are Malposed 53 When Teeth Are Extracted r)3 Results of a Break in the Peridental Membrane 53 Movement of Teeth Suteequent to Extractions 54 Saliva . ., ^-^ Ptyaliii 56 TABLE OF CONTENTS. IX PAGE Mucus 58 Albumin 60 Salivary Corpuscles, so called 61 Investing Tissues of the Teeth — The Gingivae, Peridental Membrane, Cementum and Alveolar Process. Diseases and Treatment 62 Brief Historical Review of the Development of Our Knowledge of the Diseases of the Investing Tissues 64 Names Applied to Diseases of the Investing Tissues ,. . . 64 Kiggs ' Disease 64 Pyorrhea Alveolaris 64 Phagedenic Pericementitis 65 Chronic Suppurative Pericementitis 65 Calcic Gingivitis 6o Calcic Pericementitis 65 Alveolitis 65 Dento- Alveolar Pyorrhea ■ • 66 Interstitial Gingivitis 66 Dr. Riggs' Treatment 66 Dr. Rehv^ankel's Paper 67 Gouty Diathesis as a Theory 67 Special Infection Theory 68 Serum Treatment '0 The Treatment in Vogue '''I Studies of Salivary Calculus 73 Composition ' -^ Analysis '^^ Studies of Deposit of Salivary Calculus 75 Dr. Burchard's Studies '^6 Personal Investigations of the Deposit of Salivarv^ Calculus. ... 79 Test of Saliva for Precipitate of Calcium Salts 79 Examination of Deposits on Artificial Dentures 80 Collection of Deposit on Cover-glass 81 Staining 82 Deposits Classified ^'* J Paroxysmal Characters 84 Gathering CalculiLs Direct from the Parotid Gland 86 Globulin 88 Agglutinin of Salivary Calculus 89 Consi.steufjy of the Spherules 89 Globulin and Salts Inseparable -^1 Deposits Dui'ing Illness ^1 X SPECIAL DENTAL PATHOLOGY. PAGE Chemistry of the Deposits 93 IFardening of Salivar}' Calculus 94 Knowledge of Hardening Basis for Prophylactic Teach- ing 95 Explanatory Supposition 95 Calco-globulin iu Other tSecrotions 96 Conclusion 97 Gingivitis and Pericementitis Due to Deposits of Salivary Cal- culus 99 Cingivitis. Beginning .-uul Progress of Deposit. 99 Sui)puration 100 Pericementitis. Destruction of Deeper Tissues 100 Attachment of Peridental Membrane to Hoot Mnintaincd to Level of Soft Tis.sue Remnining. 100 Pain and Soreness 101 Teeth Become Loose and Are Finally Lost 101 IMenace to General Health 102 Variations in the Position and Progress of the Deposit 102 Deposit Usually Confined to Certain Teeth 102 Conditions Contributing to Occurrence of Deposit 102 Form Which Gives Opportunity for Initial Deposit 103 Forms of Artificial Dentures to Avoid Deposits 104 Lifiuence of Masticntion in Preventing Deposits 104 Treatment of Gingivitis and Pericementitis Due to Dkposits of Salivary Calculus 105 Pemoval of Deposits ;uid Care of Tissues by the Dentist 106 Instruments and Instrumentation 106 Care of Tissues by the Dentist 109 Ciire by the Patient 110 Subsequent Examinations Ill Fixation of Teeth That Have Been Loosened as a Result of Deposits of Salivary Calculus 112 Gingivitis Due to Deposits or Serumal Calculus 115 Causes of Deposit and Conditions of Occurrence 115 Comparison of Serumal vvilli Salivaiy Calculus 117 The Gingivitis Due to the Deposit 117 Compression of Deposits by the Gingivre 118 Variations in liocation of Dcj>osits 118 Suppuration Involving Peridental Membrane 118 Treatment op Gingivitis Due to Deposits of Serumal Calculus. 120 Removal of Deposits and Care of Tissues by the Dentist 120 Care of Tissues bv the Dentist 123 TABLE OF CONTENTS. XI PAGE Care by the Patient • • 124 Subsequent Examinations 124 Gingivitis Caused by Injuries 125 General Statement of Causes and Symptoms 126 Inflannnation 126 Snppiuation l*-' Complaint of Pain Variable 127 Absorption of Septal Tissue 128 Deposits of Serumal Calculus. 128 Classification of Conditions Causing Injuries of the Gingiv.e. . . 129 Gingivitis Due to Lack of Contact of Teeth 129 Separations Following Extractions 129 Abnormalities of Occlusion l-^O Uneven Occlusal Wear l'^f> Weak Contacts I'^O Decays Beginning in Proximal Surfaces I'^l Fillings and Crowns \Yhich Fail to Make Contact 131 Gingivitis Due to Improper Contact of the Teeth 131 Abnormal Forms of the Teeth 131 Malpositions of the Teeth 132 Interproximal Wear 132 Improperly Finished Fillings and Crowns 133 Gingivitis Due to Deviations from the Normal Smooth Con- tour of Tooth Surfaces , 134 Sharp Edges of Cavities 1-^-^ Imperfect Margins of Fillings 134 CroAvns, Bridges and Partial Dentures 134 Gingivitis Due to Abuse of Tissues by Dentists in Operating 135 Injuries with Ligatures . .; 1-^'^ Injuries with Finishing Instruments and Tapes 1:56 Failures to Remove Ligatures and Pieces of Kul)l)('r Dam l;!^ Other Abuses l'*5j Gingivitis Due to Lack of Cleatiliness 13^ Lack of Natural Cleaning 1''^ Lack of Artificial Clenning l'"^"^ Gin^^ivitis Due to Errors in Cleaning Operations, Accidents, " etc l-'8 Misuse of Toothpicks '•^*^ Misuse of Rubber Bands and Silk Floss 139 Injuries with the Tooth-brush 1-^^ Accidental Inj\iri.'s lo the Gingiva- l'^9 XI 1 SPECIAL DENTAL PATHOLOGY. PAGE Frequency of Different Forms of (Jingivitis 139 History of the Attitude of the Profession Toward Injuries of the Gingivae ' 141 TTse of Non-cohesive CJold and the Filing of V-shaped Spaces 142 Discoveiy of the Cohesive Property of (iold Foil 142 Wooden Wedge 144 Diseover^^ of the Rubber Dam 145 Physiological Importance of Tooth Forms 145 Treatment of Gingivitis Due to Injuries 147 In Cases of Lack of Contact 148 Danger of Disturbing the Occlusion 149 In Cases of Improper Contact 150 Other Conditions 151 More Careful Study of Cases Necessaiy 151 An Exact IMethod of Separation Necessary to Success in Build- ing Proper Contacts 152 Perry Separator 153 Chronic Suppurative Pericementitis 159 Causes Leading to Formation of Pus Pockets 161 (iingivitis Always Precedes 161 Deposits of Serumal Calculus on Enamel 161 Injuries to Gingiva^ 161 Systemic Conditions 161 Specific Infection 162 Endameba Buccalis 162 Symptoms and Tissue Changes 164 Locations of Pus Pockets 164 Changes in the Tissues 165 Appearance of the Gingivae 165 Infection and Detachment 166 Pockets Progress Most Toward Apex of Root 167 Failures of Reattachment 167 Cases Tend to Progress 168 Destruction of Cementoblasts, Fibers of Peridental Membrane, and the Alveolar Process 168 Absorption of Alveolar Process Best Shown by Radiographs 169 Granular Condition of Soft Tissue Covering Root. . . . 171 Absorption by the Denuded Cementum of Products of Suppuration and Putrefaction 171 Complaint of Pain 172 TABLE OF CONTENTS. Xlll PAGE Deposits of JSenimal Calculus 172 Deposit Often Nodular 172 Occurrence of Deposits. 173 Deposits Contribute to Progress 173 Enlargement of Cervical Glands 174 Palpation of Submaxillary and Cervical Lymphatic Glands 174 Excitation of Salivary Glands . 175 Movements of the Teeth as a Result of Pocket Formation . . 175 Labial Movement of Upper Incisors . . . 176 Teeth May Move Forward of Normal Position of Labial Process 177 Multiple Pocket Formation 178 Gingival Abscess, Septal Abscess and Lateral Alveolar Abscess 179 Differential Diagnosis from True Alveolar Abscess. . . 181 Admixtures of Chronic Suppurative Pericementitis and Inflam- mations Caused by Deposits of Salivary Calculus 182 Treatment of Chronic Suppurative Pericementitis 185 The Key to the Treatment 185 Preventive Treatment 186 Plan for Preventive Treatment 186 Preventive Treatment Must Be by General Practitioner of Dentistiy 187 Systematic Observation and Institution of Treatment Early 187 Care to Avoid Injury to Soft Tissues in All Operations. . . . 188 Injuries to the Septal Tissues 188 Injuries to Lingual of the Tapper Incisors 189 Training of Patients 189 Palliative Treatment 190 Plan for Palliative Treatment 191 Removal of Deposits and Care by the Dentist 191 Instruments 192 Instrumentation 192 Finger Skill Very Essential 194 Scalers ^Must Be Sharp 194 Leave Roots Smooth 195 Pain in Scaling Operations 196 Care of Tissues by the Dentist 197 Care by the Patient 197 Subsequent Examinations 198 Administration of Emetin llvdrochlorate 199 XIV SPECIAL DENTAL PATHOLOGY. PAGE Surgical Treatment of Pockets 199 Tlie Use of Splints 201 Radical Treatment 202 When Indicated 202 Amputation of ]xoots 20.1 Management of Cases of Chronic Suppurative Pericementitis. . . 206 Examination 206 Kadiographs 207 Plan of Treatment for Eacii Case 208 Sentiment in Relation to the Treatment of Diseases of the Peridental Membrane 209 Al)andonment of Antiseptics in the Treatment of Chronic Su})- purative Pericementitis 210 Defense by the Tissues 218 Treatment by Cleanliness \ 213 Development of Antiseptic and Aseptic Suugery and the Use OF Antiseptics 217 Preparatorj'^ Period . 217 Antiseptic Period 218 Aseptic Period 220 Use of Antiseptics Gradually Lessened 220 Chemotaxis and Phagocytosis 221 Personal Studios 222 Chronological List of the Principal Events in the Development op Antiseptic and Aseptic Surcekv 225 Acute Ulcerous Gingivitis 230 Dentaij Pulp. Histology and Physical Functions 235 Cellular Elements 235 Odontoblasts. Fibrils of Tomes 230 Blood Vessels 236 Walls of Blood Vessels .; 237 Nerves and Nei-ve Functions 238 Sensory Function of the T'ulp 239 Pain and Touch 240 Pulp an Internal Organ 241 Pain of Other Diseases Simulates Pulp Pain 242 Sense of Touch Is in Peridental Membrane 243 Healing Powers 243 History of Efforts to Save Exposed Pulps by Capping. 244 Diseases of the Dental Pulp 248 Historical Statement 248 TABLE OF CONTENTS. XV PAGE Personal Studies of Hyperemia and Inflammation of tlic f'lilp. . 251 Teehnie of Preparing Specimens 251 Hyperemia of the Dental Pulp 254 Etiology 254 Pathological Changes 255 Symptoms 25G SequeljE 25G IneIjAmmation of the Dental Pl lp 258 Etiology 258 Pathological Changes 259 Diagnosis 261 Exposed to Carious Dentin 261 Pain 261 Chronic Inflammation of the Pulp 262 Hypertropli}^ of the Dental Rilp 262 Diiignosis 263 Treatment 264 Calcifications in the Pulp Chamber and Their Ept^^ects Upon THE Pulp Tissue 265 Classification 265 Personal Investigations , .^ 266 Calcifications Attached to the Walls of the Pulp Chamber 267 Etiology 267 Nature and Conditions of Growth 268 Protection for Pulp 268 Calcifieation More Extensive as Abrasion Progresses. . 268 Secondary Dentin Deposited Through Reflex Action ; Not a Local P'ovmation 269 Effect upon the Dentin and Enamel 271 Abraded Dentin Becomes Darker. Fibrils Die 271 Exposure of Pulp by Abrasion and Erosion 272 Effect upon the Pulp 272 Danger of Alveolar Abscess 274 Calcifications Growing Free in the Tissue of the Pulp, Unat- tached to the Walls of the Pulp Chamber 274 Variety of Forms 274 Generally No Symptoms 276 Tendency to Destroy Pulp 276 Treatment for Limitation of Calcifications Within the Pulp Chamber 276 Treatment of Abnision 277 XVI SPECIAL DENTAL PATHOLOGY. PAGE Building Up of Extensive Abrasions 278 Danger of Ajiproachiug Too Close to Pulp in Cavity Preparation 279 Treatment of Erosion 279 Formation of Calco-Spiierites 280 Artificial Formation of Calco-Spherites 281 Importance of Studies of Calco-Spherites 283 Technic of Treatment of the Dental Pulp 286 General Considerations 286 Asepsis 287 Plan for Aseptic Technic 288 Application of the Rubber Dam 288 Sterilization of Field 289 Sterilization of Instruments, Dressings, etc 289 Sterilization of Broaches Wrapped \nth Cotton 289 Technic of Wrapping Cotton on Broaches 290 Surgically Clean Hands 292 Sealing Treatments 292 Technic of Sealing Treatments with Base-Plate Gutta- percha 292 Rationale of Pulp and Root Canal ^Medication 295 Experiments with ^lodicaments Used in Pulp Treat- ment 296 Preventive Treatment of Hyperemia and Inflammation of the Pulp 298 Thorough and Frequent Examinations 299 Avoid Near Approach and Exposure of Pulp in Cavity Preparation 299 Use of Non-Con ductors 300 Treatment of Hyperemia 300 Capping Exposures of the Dental Pulp 301 Time of Complete Calcification of the Roots of the Various Teeth 303 Indications for Capping 303 Technic of Capping 303 Treatment of Vital Dental Pulps 304 Exposure of the Pulp 304 Conditions Presenting 304 Opening the Cavity 304 Rubber Dam On 305 Make Exposure with Broad Instrument 305 In Bicuspids and Molars 305 TABLE OF CONTENTS. XVI 1 PAGE III Proximal Cavities in Incisors 306 Medication to Reduce Inflammations 306 When Pain Is Uncontrollable 307 Destroying the Dental Pulp with Arsenic 307 Avoid Pressure in Sealing 307 Danger of Arsenical Poisoning 308 Subsequent Treatment of Pulp Only Partly Devitalized. . . 308 Anesthetizing the Dental Pulp with Cocain 308 Requires Pressure to Secure Anesthesia 309 When Pulp Is Not Actually Exposed 309 Opening the Pulp Chamber Preparatory to Removal of the Pulp 310 Occlusal Cavities in Molars 310 Proximal Cavities in Molars 312 Cavities in Bicuspids 312 Cavities in Incisors and Cuspids 312 Removal of the Pulp '^1^ Broaches ^^^ Technic of Removal , . . . 314 Location of Canals in Upper Molars 314 Location of Canals in Lower Molars 316 Variations in the Forms of Pulp Chambers 318 Opening Pulp Chambers in Sound Teeth 318 In Incisors and Cuspids 318 In Bicuspids and Molars 320 Treatment of Teeth Having Dead Pulps 321 Conditions Presenting 321 Technic of Treatment. Asepsis 322 Instrumentation ^^^ Seal Treatment -^23 Danger of Periapical Infection 323 Treatment of Pulp Chambers Which Have Been Narrowed by Calcific Deposits "^^^ Removal of Calcifications from Root Canals 325 Removal of Previous Root Canal Fillings 325 Fii;LiNG Root Canals -^^^ Size of Foramen and Length of Canal 326 Technic for Large Canals 3-7 Rationale of this Procedure ^28 Technic for Small Canals 328 Canals Grouped into Two Classes 329 To Prevent Evaporation of Chloro-percha '. 329 Horns of Pulp Chamber •**"'^ b XVlll SPECIAL DENTAL PATHOLOGY. PAGE Treatment of Pulps of Deciduous Teeth 330 Time of Complete Calcification and Beginning Absorption of Roots 330 Serious Results from Exposures of Pulps of Deciduous Teeth. . 331 Technic Same as for Permanent Teeth 332 Chronic Abscesses 333 Better Care Desirable 333 Filling of Deciduous Teeth 334 Acute Alveolar Abscess 336 Etiologj' 336 Pathological Changes 337 Apical Pericementitis and Pus Foi-mation 337 Absorption of Bone 337 If Pus Penetrates Periosteum 340 If Pus Lifts Periosteum from Bone 340 Variations in Burrowing of Pus 340 Distinctions between Alveolar Abscess and Abscesses Occun-ing Elsewhere 341 Infection from Pulp Chamber of a Tooth 341 Denuded Cemcntum Maintains Chronicity 341 Symptoms 343 Constitutional Symptoms 343 Local Symptoms 343 Tenderness of Tooth 343 Pain and Swelling 344 Ball-like Tumor 344 Flat Tumor 345 Painful Symptoms Disappear with Discharge of Pus. . 345 Difi'erential Diagnosis between Acute Alveolar Abscess and Certain Other Conditions 345 Sarcoma 346 Gumma 346 Aneurism 346 Cysts 346 P^xamine Fluid Contents 347 Glands 347 Eruption of Third ^lolars 347 Treatment op Acute Alveolar Abscess 350 During Apical Pericementitis 350 Secure Good Drainage 351 Through Pulp Chamber 351 Through Investing Tissues 351 TABLE OF CONTENTS. XIX PAGE Advantages of Early Incision . < 352 Incision Should Be Ample for Good Drainage 352 If a Broad Flat Tumor Under Periasteum 353 If Pus Has Not Reached Periosteum 353 Anesthesia for Incision 353 Opening Made with Phenol 353 Irrigation 354 Packing 354 Open Pulp Chamber after Acute Symptoms Have Subsided 355 Treatment of the More Severe Cases 355 Relief of Pain and General Symptoms 356 Hot Fomentations 356 Saline Cathartic. Hot Fwt Bath 356 Anodyne 356 Drainage 357 Burrowing of Pus 357 Prophylaxis as Applied to Alveolar Aliscess 300 Chronic Alveolar Abscej^s 362 Etiology . 362 Pathological Changes 363 Destruction of the T'eriapical Tissues 363 If Dead Pulp Renuiins in Tooth 363 If Periapical Tissues Destroyed by Acute Abscess. . . . 363 If Periapical Tissues Destroyed by Drugs 363 Detachments Permanent and IMaintain Chronicity. . . . 363 Classification 365 Chronic Abscess with Sinus 365 Chronic Abscess Discharging Through Root Canal. . . . 365 Blind Abscess 365 Chronic iVbscess with Intermittent Dischai'ge 365 Variations in Positions of Sinus Openings 3()5 Deposition of Subperiosteal Bone 367 Deposits of Serumal Calculus 368 Diagnosis 368 Pain 368 Tenderness of Tooth 368 Absorption of Bone and Loosening of Tooth 369 Pulp of Tooth Dead or liemoved 369 Discharge of Pus 369 Extent to Which Ccmentum Is Denuded. Examinatiim with Steel Probe 371 Radiographs 371 XX SPECIAL DENTAL PATHOLOGY. PAGE Tkeatment of Chkonic Alveolar Abscess 373 Historical 373 Treatment 375 Treatment of Root Canal 375 When Sinus Does Not Ileal 376 Cases of Blind Abscess 376 Practice in Vogue Should Be Discontinued 377 Resection of Roots 378 Technic 378 Possibilities of Healing 378 Amputation of jMolar Roots 379 Necrosis op the Maxill.e 380 Etiology 381 Symptoms 381 Treatment 382 Secure Good Drainage 383 Cleanliness 383 Extract Loose Teeth 383 Cathartics and Anodynes 384 Removal of Sequestra 384 Prophylaxis against Necrosis 386 Chronic Osteitis of the Maxill.e 388 Etiology 388 Symptoms 389 Treatment 390 Epithelial Cells of the Peridental jMembrane in Relation to Inflammations and Cyst Formation 392 Studies by German Histo-Pathologists 394 Cyst Formation 395 Systemic Effects of Chronic Infections of the Mouth 398 Dr. Hunter's Paper on Oral Sepsis 398 Dr. Billings' Investigations 401 Dr. Rosenow's Studies 403 The Organism in the Primary Focus 405 Three Groups of Chronic Foci in the Mouth 407 Defense by the Tissues 408 The Dentist's Opportunity 409 Summary 409 Oral Prophylaxis 411 General Prophylaxis 411 Oral Prophylaxis 413 TABLE OF CONTENTS. XXI PAGE The Oral Prophylaxis Treatment, So Called 415 Application to Dental Caries 416 Pit and Fissure Decays 417 Proximal Decays 418 Gingival Third Decays 419 Application to Diseases of the Peridental Membrane. . 420 Gingivitis Caused by Deposits of Salivary Calculus 420 Gingivitis Caused by Deposits of Serumal Calculus 421 Gingivitis Caused by Injuries 421 Summarj-^ 421 Mouth Hygiene 423 Popular Education 423 Care of the Mouth 425 Temporary Teeth 425 Teehnic of Cleaning the Mouth 427 The Tooth-brush 427 Movements of the Brush 429 Care of the Brush 431 The Toothpick 431 Rubber Bands and Silk Floss 432 The Syringe 433 When Gingivae Are Inflamed 436 Mouth Washes, Pastes and Powders 436 Dentist Should Put Mouth in Condition 437 When Cleaning Should Be Done 438 Training in Cleaning the Mouth 439 Artificial Cleaning Unnecessary for Some Persons 441 Irregularities of the Gingivae 442 Artificial Dentures 442 Bridges 445 Examinations of the Mouth 447 Routine Mouth Examination 448 Instruments for Routine Examination 450 General Survey 451 Critical Examination of the Teeth and Investing Tissues. . . 451 The Record of the Examination 456 The Examination Card 4;)7 Use of the Card 457 Appendix. A Machine for Grinding Microscopic Specimens 460 The Slicing Machine 461 The Grinding Apparatus 462 Tho. Grinding Disks 464 Xxii SPECIAL DENTAL PATHOLOGY. PAQE The Point Finder 464 Lap Wheels 465 Grinding Stones 465 Watering the Stones 465 Waste Water 466 Preparation of Material 466 Management of Balsam 467 Spiders and Dogs 467 Rapidity of Grinding 469 Setting the Measurement of Grinding Disks 469 Grinding Frail Material 470 The Use of Balsam 471 Removal of the Cover-glass from the Disk 473 The Use of Shellac 473 The Preparation of Shellac 474 Grinding from Crumpled ^Material 474 Difficulties in Grinding 475 LIST OF ILLUSTRATIONS. NUMBER Investing Tissues of the Teeth, Histology and Physical Func- tions 1-121 Gums and Gingiv.t, 1-24 Epithelium 1, 2 The various structures of the investino^ tissues 3 Diagrams illustrating nomenolature of the gingivae 4, 5 Crest of the alveolar process 6 Diagrams illustrating groups of fibers in gingiva* and periden- tal membrane 7, 8 Cross sections showing trans-septal fibers 9, 10 Diagrams illustrating nomenclature of the interproximal space. 11-14 Selection of teeth to show the gingival lines 15-24 Cementum, Peridental IMembrane and Alveolar Process 25-121 Longitudinal sections, deciduous incisor and investing tissues, kitten 25 Cross section, cuspid and investing tissues 26 Series illustrating the growth of connective tissue 27-42 Cementum 43-92 Cross section, human femur, Haversian systems 43 Lengthwise section of same 44 Bone in process of absorption 45 Absorption of bone over permanent tooth 46 Series illustrating the growth of bone 47-65 Absorptions of roots and repairs with cementum 66-74 Cementum showing fibers of peridental membrane 75-78 Thickness of cementum in the young and the aged 79, 80 ITypercementosis 81-92 Peridental Membrane 93-116 Longitudinal sections showing groups of fibers 93-96 Transverse sections showing fibers 97, 98 Fibers of the peridental membrane 99-101 Cnathodynamometer 102 The various cellular elements 103-111 Epithelial strings 112-116 (xxiii) XXIV SPECIAL DENTAL PATHOLOGY. NUMBEK Physical Powers of the Peridental Membrane as Shown by Planted Teeth 117-119 Rowlandson's cartoon, 1787 117 Radiograph showing absorption of planted tooth 118 Planted tooth showing absorption of root 119 Alveolar Process 120, 121 Absorption of bone of alveolar process 120, 121 Investing Tissues of the Teeth, Diseases and Treatment 122-296 Studies of Salivary Calculus 122-143 Denture with trap for collecting specimens 122 Photomicrographs of deposits 123-134 Intubation of Stenson's duct 135-137 Cheese-like accumulations 138, 139 Calculi removed from ducts of salivary glands 140-142 Calculus from human kidney 143 Gingivitis and Pericementitis Due to Deposits of Salivary Calculus 144-170 Colored drawings illustrating progressive destruction of invest- ing tissues 144-147 Teeth with deposits of salivary calculus 148-162 Photomicrograph of ground section of deposit of salivary cal- culus on a tooth 163 Illustrations showing destruction of the investing tissues. . . .164-167 Deposits on artificial dentures 168-170 Treatment of Gingivitis and Pericementitis Due to Deposits of Salivary Calculus 171-178 Set of sealers 171 Water tank with thermostat 172 Electric thermostat 173-175 Large rubber-bulb syringe 176 Tablets for physiological salt solution 177 Stay appliance for loose teeth 178 Gingivitis Due to Deposits of Serumal Calculus 179-185 Photomicrograph of ground section of serumal calculus 179 Colored illustrations showing positions of deposits in subgingival spaces 180-182 Teeth with rings of serumal calculus on enamel 183-185 Treatment of Gingivitis Due to Deposits of Serumal Cai^- cuLus 186-188 Set of Sealers 186 LIST OF ILLUSTRATIONS. XXV NUMBER Rubber-bulb syringe for patient's use 187 Position of nozzle in use 188 Gingivitis Caused by In j uries 189-215 Colored drawings illustrating injury to the septal tissue 189-191 Plaster models, radiographs, etc., showing injuries to the gingivae 192-210 Old separating files and their use 211-215 Treatment of Gingivitis Caused by Injuries 216-225 Testing contacts, and forms of contacts 216-218 Perry separators and their application 219-225 Chronic Suppurative Pericementitis 226-264 Colored illustrations, showing gingivitis and pericementitis in various stages 226-231 Panoramic radiographs of normal denture ..." 232, 233 Panoramic radiographs of ease of chronic pericementitis. . . .234, 235 Sections of normal peridental membrane 236, 237 Photomicrographs of tissue overlying pus pockets 238-242 Radiographs of cases of chronic pericementitis 243-252 Teeth with deposits of serumal calculus 253-258 Photomicrograph of ground section of nodule of serumal calculus on a root 259 Plaster model and panoramic radiograph of case of protrusion of upper incisors 260, 261 Models of cases of lateral and septal abscesses 262, 263 Drawing of pus pocket published in 1886 264 Treatment of Chronic Suppurative Pericementitis 265-295 Instruments correctly and incorrectly contra-angled 265 Set of scalers 266 Special explorers for measuring depth of pockets 267 Series illustrating positions of scalers in use 268-284 Removal of tissue overlying pocket 285, 286 Radiograph of case with stay appliance 287 Radiographs of cases showing extensive destruction of investing tissues 288, 289 Plaster models of cases in which roots were amputated 290-293 A surgical operating-room bnilt in 1887 294 Recent radiograph of elbow injured by gunshot and treated with antiseptics in 1878 295 Acute Ulcerous Gingivitis 296 Model of a case 296 XXVI SPECIAL DENTAL PATHOLOGY. NUMBER Dental Pulp. Histology and Physical Functions 297-303 Sections showing cellular elements 2f>7-299 Diagram of blood vessels 300 Photomicrograph showing thin walls of l)hi()d vessels 301 Odontoblasts and dentinal fibrils 302, 303 Diseases of the Dental Pulp 30-4-341 Hyperemia 3()-4-307 Sections showing changes in hyperemia 304-307 Inflammation 308-316 Sections showing changes in inHainmatioii 308-311 Suppuration, abscess and chronic inHaminatioti 312-314 Hypertrophy of pulp 315 Calcifications in the Pulp Cilvmber 310-341 Secondary dentin resulting from erosion 316, 317 Secondary dentin resulting from abrasion 318-320. 323-326 Secondary dentin ascribed to caries 321-322 Sections of teeth with secondary dentin 327-329 Atrophy of odontoblasts 330, 331 Pulp nodules 332-334 Cylindrical calcifications 335-337 Artificially formed calco-spherite.s 338, 339 Calco-spherite-like forms in pulp and peridental membrane. 340, 341 Technic of Treatment of the Dental Pulp 342-401 Sterilizing-oven for broaches 342 Operating-tray equipped for pulp troatme?it 343 Dish for sterilizing broaches 344 Dropper bottle 345, 346 Photographic reproductions showing effect of antiseptics on skin 347-358 Recessional lines of pupal horns 359 Radiographs of partially developed roots 360-362 Diagram showing contemporaneous calcification of permanent teeth 363 Removing carious dentin in exposing pulp 364 Split bicuspid showing form of pulp chamber 365 Opening pulp chamber of central incisor from mesial or distal surface 366, 367 Horizontal .sections of upper first molars, showing forms of pulp chambers and root canals 368, 369 Lengthwise sections of upper molars, showing pulp chambers and root canals 370-377 LIST OF ILLUSTRATIONS. XXVll NUMBER Horizontal sections of lower molars, .showing forms of pulp chambers and root canals 381 Lengthwise sections of lower molars, showing pulp chambers and root canals 378-380, 382-388 Position for passing broach into canal of distal root of any lower molar 389 Incisor split labio-lingually, showing method of opening pulp chamber through lingual surface 390-393 Differences in shadows-lengths of roots in radiographs 394-396 Diagram showing progress of calcififaiion of roots of deciduous teeth 397 Diagram showing progress of absorption of roots of deciduous teeth 398 Radiograph showing failure of absorption of root of deciduous tooth on account of abscess 399 Kadiograph and photographs showing roots of deciduous molars about bicuspid crowns 400, 401 Acute Alveolar Abscess 402-429 Series of colored drawings illustrating acute and chi'onic alveo- lar abscess 402-416 Series of radiographs showing building in of bone following an acute alveolar abscess 417-422 Giant cell sarcoma, radiograph of case 423 Cysts shown by tw' o radiographs and a lower maxilla 424-426 Alveolar abscess discharging near eye 427 Alveolar abscess involving tissues of neck 428, 429 Chronic Alveolar Abscess 430-460 Lower jaw showing destruction of bone by abscesses 430-432 Radiographs which emphasize necessity of careful diagnosis. 433-437 Radiographs showing blind abscesses 438-441 Plaster model of abscess with intermittent discharge 442 Radiographs of cases of chronic abscess 443-450 Deposits of .serumal calculus on roots in cases of chronic abscess 451-454 Root resection in treatment of clironic abscess 455-460 Necrosis op the Maxill/e 461-463 Sequestra 461, 462 Tnvolucrum causing facial deformity 463 Chronic Osteitis of INTaxill.e 464, 465 Radiograph of a case 464 Gilmer's sharp stool ]>robo and a silver probo 465 XXViii SPECIAL DENTAL PATHOLOGY. NUMBER Epithelial Cells of Peridental Membrane in Relation to Inflammations and Cyst Formation 466-476 Photomicrographs of sections through cysts and cyst vvmUs. .466-476 Mouth Hygiene 477-500 Forms of tooth-brushes 477-485 Brushing the lower gingiva? and teeth 486-402 Brushing the upper gingivie and teeth 493-497 Kubber-bulb syringe for washing interproximal and subgingival spaces 498 Brushes for artificial dentures 499, 500 Examinations of the Mouth 501-507 Examination Card and plan of recording 501-507 Appendix. Machine for Grinding Microscopic Specimens. . . .508-518 Slicing mechanism 508, 509 Grinding mechanism 510-513 Electric cut-off 514-516 Spider for mounting specimens on grinding disks 517, 518 Special Dental Pathology INTRODUCTION A STRICTLY dental disease is one that is peculiar to the teeth or their membranes, either in its causation, its nature, or in the tissues to which it is confined, and which can not occur elsewhere in the body. The tissues of the teeth are, in their histology and physiology, a distinct class. The membranes investing the teeth have peculiar histological and physical char- acters and forms suited to the functions of the teeth. These form a special assemblage of tissues, the pathology of which is unlike that of any other tissues of the body. It is this special pathology, together with the manipulation required in treatment, which has made dentistry a specialty in medicine. I have previously written a book on the Pathology of the Hard Tissues of the Teeth, in which atrophy or hypoplasia, erosion, abrasion and caries were considered. In the present volume I shall include two principal groups: Diseases begin- ning in the gingivae which may in their progress involve the peridental membrane and alveolar process, and diseases of the dental pulp and their sequelae, including acute and chronic alveo- lar abscess, necrosis, etc. It will be found as we proceed that diseases of the^ peridental membrane occur as the result of either a preceding gingivitis, which first involves the peridental mem- brane at the gingival line of the tooth; or the death of the dental pulp, which first involves the peridental membrane at the apex of the root. From other than these two points of beginning, we have practically no disease of the peridental membrane, except- ing as a result of some unusual traumatism. In both groups we are concerned with the investing tissues of the teeth, and this makes it especially advantageous to present a careful study of the physical functions of these tissues. It is also advantageous to study the pathology of these two groups, as they include practically all of those foci in the mouth which endanger tlio general health. In the chronic suj^pura- tions of the peridental membrane beginning at the gingival line Z SPECIAL DENTAL PATHOLOGY. and in many cases of chronic alveolar abscess, tlie investing tissues are detached from the cementum, and in the treatment of both we are confronted with the same problem of the impossi- bility of repair, due to the peculiar characteristics of the cemen- tum. When such detachment occurs, the pus-soaked cementum l)ecomes practically a dead tissue, which can not be exfoliated, and therefore maintains the chronic focus indefinitely. Recent investigations of the relationship of the;^e chronic foci to serious secondary lesions, demand the elimination of these foci, as well as the institution of more effective operating for their prevention in the future. During practically the full period of my practice, I have cai-efully observed and recorded the i^athological conditions of tlie peridental membrane, and for many years these diseases have been subject to special study. During the past few years T have devoted much time to their consideration, and it is for the purpose of giving my findings to the profession that this book is written. In fact, the ])ublication of this book has been delayed in order to carry on recent investigations of the method of deposit of calculus, and other matters which were considered essential to a proper presentation. A nomenclature sufficient for a satisfactory description and clear understanding of the various parts of the gingiva? and peridental membrane and their functions has been developed. Particular attention is given to the various groups of fibers and their functions in maintaining the teeth in position under normrl conditions and in tlie movements which result from the cutting off of certain groups of fibers by disease. Likewise the changes which occur as a result of suppurative detachment, and the bear- ing which these changes have on reparative processes, are presented. Diseases of the peridental moml)rane begnnning at the gingi- val margins are perhaps, of all the diseases of the dental tissues. the least well understood. This is because of an insufficient knowledge of the histology, ])hvsical functions and special })]iysiological relations and dependence upon each other, of th" tissues involved, and the failure to study the local causes leading to the establishment of the disease by any efficient system of keeping records of cases in order to note their origin and progress. I know of no other group of diseases in which such a system of study is more necessar>^ to a clear understanding. There has been much confusion of ideas regarding the pathologj" of these diseases. This is largely because of the slow- INTKODUCTTON. 6 ness of their progress. We may see cases wliicli have been progressing for twenty years, or even longer, before they have been regarded as serious, and afterward see the complete wreck of the denture. Any disease which progresses so slowly is espe- cially difficult to study in its completeness. It is not like the study of, for instance, ty})hoid fever, in which practically the whole assemblage of phenomena occur within three or four weeks. One who sees many cases of such a disease comes soon to know the groupings of tlie various phenomena, and to know the physical manifestations of the disease in all its details. In the acute form of alveolar abscess the case may begin and run its course in from two to six days, and one easily gathers the essential symptoms, but in diseases of the peridental membrane, beginning at the gingival margin, in which the rise and progress usually extend over a number of years, the difficulties are greatly increased. The different diseases of the gingivae and peridental mem- brane, as well as the various causes, are separately considered, both as to patliology and treatment. It is of the utmost impor- tance tliat these different conditions be recognized as a basis for correct diagnosis and proper treatment, although this seems not to have been done by the large majority of the profession. In medicine, an accurate diagnosis is the basis of successful treat- ment; it shouid be so in dentistry. The dentist wlio is able to make an exact and full diagnosis of the various diseases will have little difficulty in determining the best course to pursue in treatment. The names or terms given to these conditions constitute one of the important features. These names are all very simple and in each instance both the cause and the tissue principally involved are included. Such a nomenclature is essential to a ])roper undei-standi ng. Inflammations involving the gingiv;e only are definitely separated from those involving the peridental membrane, as a basis for rational preventive treatment of dis- eases of the peridental membrane, becaur-.e ging-ivitis is a neces- sary antecedent of these diseases. The fact that deposits of salivary calculus destroy all of the investing tissues ^correspond- ing to the area of detachment from the root, generally without the formation of pus pockets, requires that the inflammation caused by deposits of salivary calculus be studied apart from all other inflammations of the investing tissues. Studies of the deposit of salivary calculus have shown that the calcium element is brought into the mouth with the saliva in 4 SPECIAL DENTAL PATHOLOGY. the form of calco-globulin ; also that the deposits are paroxys- mal in character and of comparatively short duration at rather definite periods after meals. These studies indicate that the outpouring of calco-globulin results from digestion in excess of assimilation. Calco-globulin has been obtained from the saliva, also direct from Stenson's duct, and the specimens have been stained and photogTaphed. Deposits occurring in the mouth, on traps constructed for the purpose, have been examined and photographed during all stages from the initial soft to the stony hard deposits. By a specially designed lathe for grinding microscopical sections of hard substances, the deposits of both salivary and serumal calculus upon the teeth have been studied and photomicrographs made which were not heretofore possible. These studies have indicated a thoroughly dependable system of treatment for prevention or control of the destructive inflamma- tions resulting from deposits of salivarj^ calculus. In the study of the chronic suppurative detachments of the peridental membrane, in which pus pockets are formed, it will be shown that deposits of serumal calculus upon the cementum are never a primary cause of these pockets. Practically all cases may be accounted for as due to local causes, the treatment of which is usually simple, offering the key to effective prevention of this most destructive of mouth diseases, which is, of the mouth infections, the greatest menace to the general health. In the consideration of the dental pulp, enough of the histol- ogy and physiological functions will be given to enable the reader to gain the best understanding of the diseases of this tissue. It will be noted that the classification of these diseases is based upon the clinical manifestations, rather than upon microscopical examinations which can not be satisfactorily applied in practice. Radiography has enabled us to make much more accurate diagnoses of conditions within the maxillary bones than was possible previous to its use. The employment of the radiograph in the examination of cases of chronic suppurative pericemen- titis shows clearly the progressive absorption of the alveolar process subsequent to detachments of the peridental membrane from the cementum. The showing of cavities within the bone about the ends of roots, following pulp treatment in a very con- siderable percentage of cases, brings home the importance and absolute necessity for more careful technic and greater thor- oughness in the handling of root canals. This should also INTRODUCTION". 5 impress the need for more accurate diagnoses of pulp conditions and less of recklessness in pulp destruction. This book is essentially a work on preventive treatment. For practically every pathological condition discussed, the possi- bilities and methods of prevention are presented. The special aim has been to point out the value in prevention of a closer study of the patholog}'^, in order that careful observation and prompt recognition of the beginnings of these diseases will lead to better judgment and greater care in the finer details of manipulation in all operations performed. Effective prophylaxis against the dis- eases of the investing tissues can not result from the so-called oral prophylaxis treatments ; this must be brought about by the practice of prophylactic dentistry, in which the effect of every operation in preventing or causing disease will be appreciated. The place which the so-called oral prophylaxis treatment should occupy in practice will be stated. The necessity for the careful training of patients in mouth hygiene will be presented as an important element in the preventive and palliative treat- ment of most of the diseases considered. A separate chapter is devoted to the subject of mouth hygiene. More rational medication than now generally practiced is strongly urged. This applies particularly to the use of caustics and antiseptics in the treatment of both the peridental membrane and dental pulp. The tendency of surgeons toward the aban- donment of antiseptics in the treatment of wounds, on account of the effect of these in interfering with the activity of the tissues, should lead us to a similar course. Conditions in the mouth are such that it is impossible to maintain asepsis. This fact, coupled with the fact that detach- ments of the peridental membrane from the cementum produce a constantly acting irritant, place these diseases in a class to themselves, entirely different from suppurations which occur elsewhere in the body. In treatment we should appreciate the exceptional powers of the mouth tissues in combating infections and should encourage them by maintaining the limit of cleanli- ness, rather than hinder them by the use of drugs which inter- fere with their activities. In the consideration of so many closely related conditions, numerous duplications of statements occur. After a review of the completed text, it seems desirable, for the fullest understand- ing of each subject, that these repetitions remain. Practically all of the illustrations are original. A consid- erable number are reproduced from my previous writings in the 6 SPECIAL DENTAX. PATHOLOGY. American System of Dentistry and my own books and articles in dental journals. Others have been prepared especially for this book. A lathe designed and constructed for the purpose of grind- ing microscopical sections of hard substances, such as teeth, deposits of calculus, etc., is illustrated and described in the appendix. INVESTING TISSUES, HISTOLOGY, PHYSICAL FUNCTIONS. THE INVESTING TISSUES OF THE TEETH GINGIVAE, PERIDENTAL MEMBRANE, GEMENTUM AND ALVEOLAR PROCESS HISTOLOGY AND PHYSICAL FUNCTIONS THE GUMS AND GINGIVAE ILLUSTRATIONS: FIGURES 1-24. THE gums clothe the alveolar processes and the hard palate, and the gingivae invest the gingival portions of both the roots and crowns of the teeth. These divisions of tissue join each other by continuity without apparent demarcation at the crest of the alveolar process.* That is, there is nothing on the surface to indicate a change in the character or quality of the tissue. But at this point the soft tissue at once passes across between the adjoining teeth, through each interproximal space, and joins together the soft tissues covering the buccal and labial parts with the lingual parts, and surroimds each tooth. In doing this the teeth are completely invested with a soft tissue alveolar process. If this tissue were dissected away from the bony alveolar process and the teeth smoothly removed, it would consist of a considerable piece of tissue reaching around the arch, including the third molar on each side, through which there would be a hole (alveolus) corresponding to each tooth. While these divisions of tissue have much in common in their histo- logical make-up, the gingiva) have tissue characters and func- tions not possessed by the gums. It therefore seems best to describe the characters common to both first, and then under the more specific definitions, to describe the gingivae. The gums consist of soft tissue noted for its compact inelas- tic firmness, which spreads from the crests of the alveolar * While I have long considered the above the proper line of division between the gums and gingivae, I have not heretofore had the courage to include so much tissue under the name of the gingiva?; but when I undertake to write a full description of these tissues, it seems absolutely necessary that the division bo so made, because the crest of the alveolar process marks the logical boundary of the gingival covering of the teeth. 8 SPECIAL DENTAL PATHOLOGY. processes and covers the alveolar ridges well down and away from the teeth in all directions. Then a change in character to a soft mucous membrane occurs, which is reflected on the labial and buccal portions as the mucous membranes of the lips and cheeks from both the upjier and lower arches. On the lingual side of the lower jaw it is much the same, the hard portions pass- ing into the soft flexible mucous membrane of the floor of the mouth. In the upper jaw the dense membrane spreads over the entire i)alatal surface, back as far as the junction of the hard and soft palate. This hard inelastic tissue is known as the gums. Curiously enough, the plural foiTa of the word is gener- ally used, though the singular, gum, will be heard occasionally when the reference is to some particular spot. We also say gum tissue, and use the singular form in other such combinations. The fibrous mat. The basis of the gum tissue is a thick mat of inelastic fibers. Many of these fibers are large and are branched and connected in every direction in rather short lengths, forming a dense net- work, or mat. The periosteum, which is very firmly attached to the bone over this region, is also veiy closely interwoven with this fibrous network. In this union the two tissues retain their identity. That is, the periosteum retains its usual closely coherent form, and the fibrous mat of the gum tissue also retains its form, but the two are so united by interlocking of fibers as to prevent sliding movements of the one upon the other or upon the bone. This gives the parts their characteristic hardness and immobility. One should have a clear understanding of the difference between such an immobile tissue and a. very mobile tissue. If two fingers of one hand are placed on the back of the other hand crosswise, and if, while pressing firmly, the fingers are moved as far as the sliding of the skin will allow and the skin moved back and forth, it will be noticed that it will slide considerably. This will differ much in different individuals; in some it will move an inch or more, in others less. The so-called i)ulps of the palmar surfaces of the fingers are rather soft masses of tissue. If the pulps of the two middle fingers are placed together and moved upon each other with firm pressure, it will be noticed that this tissue, while soft and elastic, is comparatively immobile — much more immobile than the skin on the back of the hand. The gums are generally immobile. To demonstrate this, one may dry any part of the gums with a napkin and place the dry finger upon this Fig. 1. Fio. FlO. 1. Stratified squamous epithelium covering tlie alveolar process: c, Corne- ous layer, p, Papilla of connective tissue. Noyes. Fig. 2. Stratified squamous epithelium from unattached mucous membrane of the mouth. The corneous layer is absent. Noyes. *1 Fig. 3. Fig. :{. Loiif^ilinlinal soction thiougli the giii>ii\;i !iiiTnen as well. Up to the present time there has been surprisingly little study of these tissues in their healthy state, or of their functions or their physiological relations to the teeth and surrounding parts. What study has been given them, has been mostly of the empiri- cal sort, or clinical studies that have not followed individual cases from early enough in their beginnings, nor long enough in their progress, to obtain the best results as studies of pathology. For these reasons, every part of this tissue, as it appears in health, should be studied both anatomically and physiologically as closely as possible, with our present means. Even to-day, THE GINGIVAE. 13 any one who undertakes this study will find the literature very scant of facts bearing upon this particular subject. I shall be compelled to depend very largely upon my personal studies for what I may present. PARTS OF THE GINGIVA. The parts of the gingivae are the body, the free gingivce and the septal gingivce. The body consists of that tissue which rests on the bony alveolar process, and forms a soft tissue extension of the alveolar process as far as the gingival line of the teeth. The free gingivae and the septal gingivae consist of that tissue which is grown upon the body, which encircles the gingival portion of the enamel of the crown of each tooth. Toward the occlusal, the free gingivie thin down to a knife-edge margin, which I shall generally call the crest of the gingiva?. (See Figures 4 and 5.) The free gingivae may be conveniently divided into parts by naming the parts of the crown of the tooth against which they are imposed; viz., the buccal gingivce, the labial gingivce, the "Ungual gingivce. Those portions which occupy the interproxi- mal spaces are the septal gingivce. The term subgingival space is given to the space between the free gingiva and the enamel which it covers. The body of the gingiva. The body is attached to the gums by continuity of tissue on the labial, buccal and lingual sides of the teeth ; and to the bony alveolar process by the fibers of its periosteum. It is attached by the fibers of the peridental membrane to the gingival portion of the roots of the teeth from the level of the crest of the bony alveolar process to the gingival line. This attachment to the root is on the average about two millimeters in width, encircling the root. The fibers of the periosteum are short and their identity is quickly lost in the formation of a dense membrane, to which the superimposed tissue is united. (See Figure G.) In any certain regions (except those of the actual attachment of tendons directly to the bones) in which strong attachments are to be made to the bones by attachment to the periosteum, the periosteum forms a membranous-like layer in that part of its thickness farthest from the bone, or in its outer layers, as op])osed to the inner layers which lie u])on the ])one. Nearly all of the muscles which are attached directly without tendons, are united to such a layer of 14 SPECIAL DENTAL PATHOLOGY. the periosteum. I have found this form of the periostemn com- mon about the crests of the alveolar processes. On the other hand, the fibers of the peridental membrane of this region are long and much in evidence in properly stained microscopic sections. In these attachments the periosteum retains its character of close adhesion to the bone as described above, and unites sud- denly, but very firmly, with the other tissue, so that there is not much spreading of fibers from it. The peridental membrane continues without change of form in the portions next to the cementum to the limits of its attachment at the gingival line. In this part of the peridental membrane the fibers are very plentiful, thick and strong. They radiate in part to the crest of the bony alveolar process, and in part to the soft tissues. Groups of fibers in the GiNGiviE and peridental membrane. The fibers of the peridental membrane form certain rather definite groups, in addition to which there are many scattering fibers. All of the groups, in both the gingivae and peridental membrane, which deserve special description, will be mentioned here, in order that their relationship may be understood. Begin- ning with those fibers attached to the cementum at the gingival line of the tooth and progressing toward the apex of the root, we find the following groups : The free gingiva group, consisting of those fibers which pass out from the cementum near the gingival line of the tooth and then extend occlusally into the free gingivae. The trans-septal group, consisting of those fibers which pass across the interproximal space, connecting the proximal sur- faces of the roots. Their attachment to the roots being between the gingival line and the level of the crest of the bony alveolar septum. The alveolar crest group, consisting of those fibers which pass out into the body of the gingivae and are attached to the crest of the bony alveolar process. The horizontal group, consisting of those fibers which pass out at right angles to the long axis of tlie tooth and are attached to the bone of the alveolar process a little below the crest. The oblique group, consisting of those fibers which pass from the cementum in an oblique direction occlusally, and are attached to the bone of the alveolar process. These oblique fibers constitute the body of the peridental membrane, or the fibers which cover the main body of the root portion of the tooth. THE GINGIViE. 15 The apical group, consisting of those fibers which are attached about the apical portion of the root and extend in fan- shaped bundles to the surrounding alveolar process. The free gingivas group, the trans-septal group and the alveolar crest group extend within the gingivae, while the hori- zontal group, the oblique group and the apical group are within the bony alveolus. The free GiNcrvjE group. The fibers of this group extend outward for a short distance from the cementum, and then turn occlusally and are distributed to the free gingivae. This group of fibers encircles the tooth completely, but is much thicker and stronger on the labial, or buccal, and lingual than on the proxi- mal surfaces. As seen in longitudinal labio-lingual (or bucco- lingual) sections cut through the tooth and its investing tissues, it is a small, rather thick tuft of fibers turning toward the incisal (or occlusal), but if we consider the entire circumference of the tooth, the fibers of this group make up quite a mass of tissue, contributing to the rigidity of the gingivae. It is the smallest of the groups of the gingival fibers of the peridental membrane. This group probabl}^ has a considerable influence in maintaining the free gingivae in their positions of close adaptation to the teeth. (See Figures 3, 7 and 8.) The trans-septal group. The fibers of this group arise from the proximal surfaces of the gingival portion of the roots of the teeth, and pass across and through the septal gingivae over the bony septum from tooth to tooth, and from tooth to tooth, recurring in each interproximal space, attaching the teeth together continuously from one third molar around the arch to the third molar of the opposite side, in both upper and lower arches. In a good many instances this group of fibers is com- posed of a number of bands which pass irregularly across from tooth to tooth. These are sometimes intermingled in a plaited or interwoven form. In studying these, it seems that they are capable of making the pull as well as, or better than, those which pass directly from one tooth to another in a straight line. The effect of these fibers is to bind the teeth more firmly together in the mesio-distal direction and especially to hold the contacts of the teeth tight. In histological sections which are cut horizontally through two or more teeth and their investing soft tissues, beginning with the crests of the free gingivae and going rootwise as the sectioning proceeds, we come upon this group of fibers passing 16 SPECIAL DENTAL PATHOLOGY. from tooth to tooth, and always find it strongly expressed. It is composed of many strong fibers, even after scattering many others upward into the septal gingivae. Often, in studying these, it has seemed to me that all of these fibers could not be attached to the cementum of the tooth, there are so many, and that some of them must arise within the tissue. These fibers have a work to do of physiological importance that has been mentioned, and it will shortly be discussed. (See Figures 8, 9 and 10.) The ALVEOLAR CREST GROUP. The fibers of this group pass over to and are inserted into the crest of the alveolar process. This group has sometimes been called the dental ligament, though it has not the characters of a true ligament. These fibers appear to best advantage in longitudinal labio-lingual (or bucco-lingual) sections. In studying the structure in such sec- tions it is often apparent that the periosteum covering the alveolar walls extends over the curve of the crest of the alveolar process and a short distance on the labial (or buccal) surface, to give place for the attachment of this group of fibers. This group forms a strong band of fibers completely encircling the tooth. It is, however, much stronger in its labial, buccal and lingual than in its proximal portions. The function of this alveolar crest group of fibers is to assist the horizontal group in sustaining the tooth in its position in its alveolus, especially against lateral motions, and yet allow that slight motion necessary to the tooth in performing its function in mastication. This will be better understood after studying the pull and the balancing of the pulls of ditferent groups of fibers, and the influences of disturbances brought about by inter- ferences with this balance of the pull exerted by the various groups of fibers upon the teeth. (See Figures 3, 7 and 8.) The free gingiva. The free gingivip are soft tissue processes growing out from the body of the gingivae and covering a portion of the enamel surface of the crowns of the teeth. They are on the labial, buccal and lingual surfaces of the teeth, and join the septal gingivae at the angles of the teeth. This part of the tissue has no attachment to the teeth, after passing occlusally of the gingival line, but is simply closely fitted about them; hence the term free gingivcB. The height of the free gingivae upon the teeth is variable, from one to five millimeters, sometimes even higher in children. In rising on the gingival portions of the crowns of the Fig. 7. Fig. 8. Figs. 7 and 8. Diagrams illustrating groups of fibers of the gingivae and peridental membrane. Fig. 7. Bueco-lingual section through a bicuspid tooth and investing tissue. F, Free gingiva> group of fibers, ac, Alveolar crest group of fibers, ii, Horizontal group of fil)eis. o, 01)lique group of fibers. A, Apical group of fibers. B, Bone of alveolar process. Fig. 8. Mesio-distal section througli two bicuspiils and septal tissue. F, F, Free gingivae groups of fibers into septal gingiva, t, Trans-septal group of fibers from tooth to tooth. AC, AC. Alveolar crest groiips of fibers, H, il, Horizontal groups of fibers, o, o, Oblique groups of fibers, a, a. Apical groups of fibers. B, bony septum of alveolar process. ♦a ^te|g^§l^ii^ §Jiy 'lMS0^-^0Jk. "^Ss Fig. 9. i'lG. lu. Fig. 9. Cross section of the eontral ami lateral incisors a little to the incisal of the crest of the alveolar sei)tiirn. a, Portion of central incisor, b, Lateral incisor, c. Pulp elianiher of lateral incisor, d, d. Ceinentiiin of central incisor, e. e, Cementum of lateral, f, Trans-septal fibers of the peridental inenil)ran(> extending from tooth to tooth continnonsly. These ar(> attached in the cenientuin of each tooth, g, g, Fibers of the peridental nieiidiranc, which Join with the coarse fibrous tissues, h, h, of the gingivae, j, j, Epithelial covering of the gingiva-. Fig. 10. A portion of the jieridental nieinl)rane between two incisors of a young sheep, showing the trans-septnl fdiers extending from tooth to tooth. Noyes. ^P/une of oc ciasat ■rfaces Plum of occ/u5a/sur£aces_ F/am of rnafqirC of a/i/eoiar sept U 771 Fig. 11. F/ane of marain of a/veo/ar septum Fig. 12. /Marain of a/veo/ar sepTum\ Fig. i;'.. uccal Embrasure Fig. 14. l'i(i. 11. Dingraiii to illustrate shape of interproximal space. If the rectangular liaiiic is jilacfd between two spheres which are in contact at the point indicated, the space within the frame and between the two splieres would be that of an interproximal space between the bicuspids and molars, which might be described as a rectangular section of a biconcave sphere. Fig. 12. Diagram to illustrate the three divisions of tiie interproximal space. The buccal end)rasure consists of that portion of the interproximal space to the buccal of the contact point wliieh normally is not filled by the septal gingiva. Tlu^ lingual embrasure consists of the corresponding portion of the interproximal space to the lingual of the contact point. The septal space consists of that j)ortion of the inter- proximal space which is normally filled by the septal tissue. This space may be ilescribed as a pyramid set upon a rectangular solid. Fk;. \?>. Diagram to illustrate the areas on the proximal surface of a tooth. The buccal embrasure area, the iingual embrasure area and the septal area are names given to those poll inns of the ])roxiinal surface of a tooth wliich correspond to the similar divisic.ns of the interproximal space. Fig. 14. Diagram to illustrate the relation of the embrasuri'S to the point of contact. The portion of the interproximal space whicli is nornuilly open (to the occlusal of the septal tissue), is divide a buccal embrasure and a liiii^,'^.i- i i Epithelium, k, k, Coarse fibrous tissne of the gums. 1. i. 1. Hloo.l vessels t.a- versing the peridental membrane, m, Saciib.s of p.T.nauenr tooth, o, Periosteum p, Attachment of labial muscles. Th- intention of xW illnslrafon .s to give a full liew of the peridental membran.-. an,! tl,. nlatiun^ m llir tooth. ,n-,nhran,. and alveolar wall. Fig. 26. Fig. 26. Cross section of cuspid tooth with peridental membrane and alveolar wall cut through the thickened rim at the gingival portion of the alveolar wall, from a man forty years old. The membrane was very thin and firm, and a large piece of the labial wail of the alveolus adhered to the tooth when extracted. It represents an extremely thin peridental membrane, while Figure 98 represents one that may be regarded' as thick, a, a, Peridental membrane, b, b, Cementum. c. e, Alveolar pro- cess, d, d. Dentin. It will be observed that most of the blood vessels of the peri- dental membrane lie in depressions in the alveolar wall. THE GINGIViE. 21 The hokmone. In the human body and in the bodies of animals there are a considerable number of ductless glands, large and small, some of which have been carefully studied, and others have not. Of these the spleen is much the largest. Its functions have not been completely made out, but it seems to have a relation to blood formation. The other ductless glands in their normal state are very much smaller. Perhaps the most important of these, both in the physiological sense and in pathological relations, are the thyroid gland and the suprarenal glands. The former is located about the trachea, and the latter in the suprarenal capsule of the kidney. The thyroid gland is subject to many changes and diseases, the most important of which is exopthalmic goitre, due to the production of a greatly increased amount of secretion, which acts as a systemic poison. The removal of this gland results in a disease called myxedema in adults, or cretinism in children, which may terminate fatally. The central and one lateral lobe are usually removed, also part of the remaining lateral lobe may be removed, with great benefit to patients suffering from exopthalmic goitre. To destroy the suprarenal glands, and they are liable to be destroyed by tuberculosis, is to bring on disease of a wasting character, which ends in death. To remove these bits of tissue by operation, has a like effect. The brain, the thj^roid gland, the suprarenal gland, the liver and muscles form a group of organs whose function is to convert potential into kinetic energy. That is to say, latent energy is converted into motion and heat in response to adequate stimuli, but if these stimuli are too intense, as a result of severe muscular exertion, strong emotion, traumatism, toxins, etc., the cells, especially those of the cerebellum (more specifically, the Purkinje cells) become exhausted and may be permanently disintegrated. Crile's theory of preventing shock consists in weakening or breaking the kinetic chain at any point. There are two ways of breaking this chain. One is by anesthetics which prevent the brain from receiving psychic shock and the other b}^ blocking the nerve tracts to prevent the brain from receiving tlie shock of traumatism. Both must be employed to carry out Crile's plan. In the study of these ductless glands, it has been found that each produces a chemic body, or several of them, known as hormone, pi. hormones (Greek), meaning to excite, to arouse. This chemic substance is different for each ducth'ss gland; that is, each ductless gland secretes or elaboiatcs its own liorinone. 22 SPECIAL DENTAL PATHOLOGY. These are formed, we may suppose, much as other secretions, but instead of being conveyed to their destination in ducts, they are delivered immediately into the blood stream passing through them, and in this way are carried to the organ with which they are associated, and which they arouse to action. The organ excited in this way may be at a distance from the gland forming the hormone. It seems very curious that just a little bit of duct- less lobulated glandular tissue, like the suprarenal glands, should have so important a physiologic function. The drug adrenalin is derived from the suprarenal glands of animals. We do not know but that some one may yet discover that these ductless glands distributed in the septal gingivjE, may also have some important function. DEVELOPMENT OF THE GINGIVA. Well-known facts warrant the statement that after the intra- uterine period, or after the animal of whatever kind has entered upon an independent existence, new tissues needed in growth are not developed until other conditions have rendered their func- tion necessary. Certainly a bony alveolar process, creating an alveolus, is not developed until there is a tooth around which to build it. In the same way, a gingiva does not grow until there is a tooth about which it may entwine its tissue. When a child is born a primary alveolar ridge is found, which is serving as a housing for the developing teeth. When a new tooth makes its way to tjie surface, this primary alveolar ridge about it is being absorbed to give it exit, and an alveolar process of bone is forming around it. The soft tissue covering of this is simple gum tissue. There is no appearance as yet of the body or processes of the gingivse. As the crown of the tooth is pushed forward, a considerable part of this gum tissue is absorbed from over it, but a remaining part is pushed aside. Just at the time of the release of the coming tooth from restraint, by the absorption of the bone covering it, the tooth comes forward quickly, so that within a very few days it is finding its occlusion with its fellow of the opposing maxilla. In this last rapid movement any part of gum tissue in the way is simply pushed aside. This often gives the soft tissue about the new tooth a ragged appearance for a few days. These tissues seem to be overfull and swollen ; the embrasures may be overfull with the soft tissue standing out of them in festoons. The child may complain of some transient pain from biting food upon this, but THE GINGIVA. 23 within a few days it is trimmed down to better dimensions by absorption. The proper forms and structure of the gingivas have not yet grown. There is not only absorption, which reduces the surface form of the tissue, but also absorptions everywhere tvithin the tissue and growth of those tissue forms belonging to the gingivae proper. This is rapidly built, the new displacing the old, and within a month or two the gingival tissue will have been com- pleted and ready to perform its usual functions. The teeth are apt to present in pairs, of like kind one on either side of the mouth, or four, including the teeth of both upper and lower jaws, and as these erupt the growth of the proper membranes and gingivas for pair after pair, lower and upper, is proceeding. The changes which take place in these tissues during this period are very rapid. The children, however, if healthy, go on through it all with only a twinge of pain now and then, when they forget and bite food against some bit of ragged tissue freshly pushed aside. It is repetition after repetition of this process, with but little variation, from the time of the eruption of the first of the deciduous teeth until the last of the permanent teeth. During these growths of the outward forms, the tissues are making interstitial growth. The fibers of the gingival portion of the now scant cementum are growing and forming their groups. These groups include the alveolar crest group, running out to the crest of the alveolar process or to the condensed tissue of the surface of its periosteum, also scattering fibers which extend into the body of the gingivae. The group of fibers, turn- ing occlusally to form the free gingivae group, take their places. The fibers of the trans-septal group, which tie the teeth solidly together mesio-distally, grow out through the septal tissues and form their junctions with each other, making these important groups solid and strong. The gum tissue, with its coarse fibrous mat, is changed for a finer network united with the fibers from the peridental membrane. The length of the body of the gingivae increases as the teeth move farther out from their liony alveoli, and form longer soft tissue alveoli. Finally, while all of this is in progress, the epithelial cover- ing is being reformed. Indeed this tissue is being actively regenerated during life, but during this time it is rapidly chang- ing its qualities and forms, the cells becoming smaller and more closely interwoven. The mass of cellular elements become more and more thickened. The interdigitation of fine, closely set con- 24 SPECIAL DENTAL PATHOLOGY. nective tissue fingers into this epithelium is grown and brought into complete form throughout every part of the tissue. During this time the outward form is not neglected. As growth proceeds, more and more of the crown of the tooth pro- trudes through the gingivae and the depth of the subgingival space is diminished. The changes are grown in the gingival tissue to accomplish this, and go on continuously to the adult period. The tissue is trimmed down here and its fulness increased there until an even smoothness of foim is produced in the whole compound of soft and hard tissues which gives a smooth exterior with an intimate network of soft tissues wound about the teeth. This fills perfectly every interstice between and about them in such a way as to prevent lodgments of debris or food occurring at any point. Such is the picture of a perfect development. Unfortu- nately, we do not always find it so perfect, nor do we always employ the best means to correct and smooth over and improve the imperfect points, or protect those which are good, from abuse. The fibers from the peridental membrane distributed in these tissues serve to bind the whole group into a solid mass, or into a mass that has a very powerful controlling effect upon the establishment of the dental arch along right lines, and maintain- ing it in this form. The development of any inflammation in this tissue serves to soften the fibers and causes them to stretch more easily, or even causes them to swell and occupy too much space. This often throws this tissue out of form, interfering with its close adaptation to the teeth, and roughening the mar- gins of the free gingiva?, causing them to receive lodgments instead of shedding such material away during the process of mastication, as they should do. This will be studied more in detail later on. The SUBGINGIVAL SPACES. The subgingival spaces have been sufficiently defined. Any particular subgingival space will be located bj^ naming the tooth to which it belongs, as, the lower left c_entral incisor subgingival space. The parts may be desig- nated by naming the surfaces of the tooth which are covered, as the mesial, distal, lingual, labial or buccal subgingival spaces, for each tooth. If it should become necessary, and it will, we can particularize almost any part of the subgingival space, as the subgingival space at the disto-buccal angle of the upper first bicuspid, etc. Wliile we name these various parts, it should be particularly noted that the subgingival space really encircles the *^v:„--* :'^i7!^vr}^^/ Fig. 21 JSTaI "y*^^***!*^ i^^f**mK^- ^^>^^4^-s*^".'>.»»-^ Fig. 44. Fig. 14. Lengthwise section from the same bone, as illustrated in Figure 43, showing the Haversian systems and their canals cut lengthwise. A, Subperiosteal bone. B, A Haversian canal. Fig. 45. Fig. 45. A photomierograpli of bono in process of absorption, a. Line of absorption showing the lacunie of Howship. Fig. AC). Fjg. 46. Osteoclast absorption of bone over permanent tooth: oc, Osteoclasts. B, Bone of crypt wall, p, Fibrous tissue of follicle wall, a, Ameloblasts. Noyes. THE GINGIVA. 25 entire circumference of the tooth without break. We divide it into parts by these names, for convenience in description. The labial or buccal subgingival space means simply that part of the general subgingival space completely surrounding the tooth, which covers the labial or buccal surface. It will be noted from the above that I have made use of the same terms in naming the parts of the gingiva? and subgingival space as have been previously used in the descriptions of the surfaces of the teeth. Exploration of the subgingival spaces. Some of the worst forms of disease of the peridental membranes begin in the depths of the subgingival spaces about the attachment of the tissue to the teeth. Therefore, the exploration of these spaces is of first importance as a preparation for the early detection of diseases of this character. This exploration may be made with any ordinary thin, flat scaling instrument, the sharp angles and working edge of which have been rounded off. Instruments made especially for this purpose are to be preferred. These will be described, and detailed instructions for their use given, under the consideration of examinations of the mouth. In the examination of a number of persons, ranging from eight to forty years, one will gain a correct idea of the changes which occur in the depth of the gingivae as age advances, which will be very useful, and can not be so well learned in any other way. Experience in subgingival examinations will enable one to detect the beginnings of disease at the attachment of the peri- dental meml)rane. For this purpose, such a course of experi- mental study is actually essential. One should examine hun- dreds of cases of normal gingiva? before he is ready to study diseased conditions of this tissue. In making such a series of examinations, one will obtain much other valuable information regarding the subgingival spaces. It will be found that the distance from the incisal edge of the central incisor to the gingival line is much greater upon the labial surface than on the proximal surface, yet the gingivic will be longest on the proximal surface. This is because of the form or direction of the gingival line around the incisor tooth. This line is curved upon the labial surface with the concavity toward the incisal edge of the tooth. It passes around the proxi- mal surfaces in a curved line which presents its convexity toward the incisal edge of the tooth. This foi-m of the line of attach- ment, the gingival line, is common to the incisor teeth and the mesial surfaces of the cuspids, above and below. The distal 26 SPECIAL DENTAL PATHOLOGY. surface of the cuspid usually lias only a slight curve toward the incisal. On the bicuspids and molars the usual course of the gingival line is more nearly directly around the tooth. (See Figures 15 to 24.) On some teeth the gingival line has irregularities which one should be able to recognize. These irregularities consist in what I have called bridges and pitfalls. As the instrument is passed around the tooth feeling the attachment, it may strike a bridge, a point where the attaclmient is higher on the crown. At this point there is a spot of thickened cementum that has lapped a little more than usual upon the enamel. On carefully lifting the end of the instrument onto this, it is often found to be of only slight extent and then again drops to the general level. On the other hand, the instrument may drop into a depression in the line around the tooth. These also may be very narrow, after which the line resumes the general level. It is essential that one should become well acquainted with these, so that he may not mistake them for beginning pus pockets. FUNCTIONS OF THE GINGIVA. A PEOTECTivE TISSUE. The function of the gingivtB of first importance is that of a protective tissue. This is a passive function exerted through the form and solidity of its structure, as it is fitted and wound about every part of the teeth, filling smoothly all interstices and shielding the tissues beneath. When this form is good the membranes of the teeth will be well pro- tected from injury. When this form is not good, these will be more liable to injury. The hard tissues of the teeth become useless without their soft tissue investment. Their usefulness depends directly upon the strength and healthfulness of that investment. It is not enough that the gingivae by the aid of the bony alveolar process hold the teeth strongly in their positions. The forms which they entwine about the teeth must be such as will shed off the debris of mastication and prevent all lodgments about them, which in their decomposition would give rise to offensive and disease- producing compounds. To do this, every part of the surface of the gingivae must be of such form as to fill all interstices full enough, but not too full, and thus be effective for both cleanli- ness and accommodation of food movements in the acts of masti- cation and deglutition. The outward form of the gingivae in and of itself, is of the utmost importance. The maintenance of this is one of the first THE GINGIViE. 27 elements of good service in dentistry. Any deviation from the best form constitutes a barrier to the health of the teeth and their investment — the gingivsB and the peridental membranes. In the past, dentists have treated the gingivas as unimportant, and have not studied them. Often they have wantonly destroyed them, especially the septal gingivae, in connection with the filling of proximal cavities. Now we are finding the reward in an increase of disease beginning at the gingival line. For a number of years I have, whenever opportunity offered, studied conditions controlling deposits upon artificial dentures. I have worn a plate myself, and often have had several, upon which I could study places of deposit at will. In every case a depression has meant a place of deposit of some I kind. In some of these food lodges, remains and is decomposed ; ' in others perhaps calculus gathers; in others there may be a cheesy deposit, or some form of debris. Deposits upon artificial dentures are in different positions from deposits in the normal mouth. The whole surface of the plate may become susceptible of receiving and holding deposits. In the mouth that is normal there is but one deposit on the soft tissues, and that is mucus which renders the surface of the epithelium slippery, so that material of almost any kind glides easily. This is normal and is present in every mouth. It is, however, sometimes in abnormally large quantity, and some- times in scant quantity. This seems to have little in common with other deposits. A short gingiva which causes a depres- sion about a tooth generally makes a place for the lodgment of calculus or cheesiform deposits. True, it makes some difference where it is located. If on the buccal surfaces of the molars, it is certain to catch calculus if any at all comes into the mouth. If there is much calculus coming into the mouth, it will catch some of it, no matter where it is located. The same is true to even a greater extent with the cheesiform deposits, which will be studied later. One should understand distinctly that these deposits, other than mucus, may occur anj^iere, where there are hard tissues or mechanical appliances on which they can lodge. In the mouth the deposit can not occur except on the teeth or some hard substance placed in the mouth. It never adlieres to the mucous membranes or other soft tissues. If present, as sometimes occurs, in soft tissue cavities, as in the tonsils or nose, the initial deposit is on some hard or dead substance which furnishes a nidus. A be ginning is never madeo n living soft tissu e. This 28 SPECIAL DENTAL PATHOLOGY. may be regarded as a statement in pathology, but its basis I belongs to physiolog\\ The mucus is practically the only sub- 1 stance that is deposited upon the ~g()ft tissues. This deposit renders these tissues, and all other tissues of the mouth indeed, slippery, and in this way performs a very important function. Maintenance of the teeth in the line of the arch. A second function of the gingivae, perhaps in a degree a part of the first, is the maintenance of the teeth in the line of the arch. Q^'he influence of the bone forming tlie alveolar process has been much overrated in its importance in maintaining the teeth in their positions. Hard and rigid as the bones of the skeleton seem in the dried state, bone is a very plastic tissue during life, and is bent about in almost any direction by a constant artificial pull. In the treatment of clubfeet I have seen the bones of the lower leg bent much out of their normal shape by a compara- tively light continuous pull upon them. This was effected by light rubber straps attached to the upper part of the leg by adhesive plaster, and reaching to the feet, to make tension in certain directions. When these straps are released and the muscles and nonmuscular tissues of the connective tissue group resume their functions, these bones quickly return to their normal form. The bones are good as holding against a stress suddenly applied and then released, but not for a continuous stress out of the normal directions. This is especially true when there is an interference with the normal action of the soft tissues for the time. When a lower first molar is extracted at a certain time of life, its alveolus is filled with bone, and the alveolar process, as such, disappears. The gingivae are swept away, and a cicatricial tissue is formed in the space to which the ends of the fibers of the trans-septal group are fastened. The shrinkage of this cicatrix and the pull of the trans-septal group of fibers drags the second and third lower molars to the mesial and tips them mesially until their occlusal surfaces do not meet their fellows correctly. These teeth are literally dragged through the bone, endwise of the bone, where there is no possible chance for the bone to be bent away. The solid bone must be moved, or when it can not be moved in substance, it will be moved by absorption in one direction, and building in, in the other. It will not stand against a connective tissue constancy of stress. We have been long in finding that the connective tissue group, other than active muscles, has a great function in directing the building of the THE GINGIVA. 29 body, holding organs in their places in health, and bringing them back to place when the correction of conditions will allow them freedom of action. These, indeed, are the most active of the tissues in maintaining the phylogenetic play of forces in shaping, trimming, forming and maintaining the development of the body in its general ancestral forms, and yet with the finest sense of ontogenetic development, or the shaping of the individual in all of its parts. There is no place in the human body where we find as fine examples of this play at control of form by the non- muscular connective tissue as in the gingivae, or so much harm from its influence when the conditions have given them a wrong direction. This will necessarily come into discussion often in pathological studies of the influence of the various tissues. 30 SPECIAL DENTAL PATHOLOGY. THE CEMENTUM, PERIDENTAL MEMBRANE AND ALVEOLAR PROCESS ILLUSTRATIONS: FIGURES 25-121. The cementiim and peridental membrane and the correla- tion of these two tissues in health and disease are of the highest degree of importance, yet of all of the dental tissues, these are the least well understood. It is quite essential that one should have a clear understand- ing of the physiology of the several tissues of the teeth, and their physiological and pathological relations to the tissues with which they are directly connected. One should know how these act and react toward each other, the limitations of their powers in recuperation following disease or accident, and the more general questions along this line. If these are well understood, it will be comparatively easy to comprehend the pathological conditions, their symptomatology, and wliat may and what may not be accomplished in treatment. Knowledge of what can not be done is as important in practice as knowledge of what can be done. Many dentists are losing time and prestige in trying over and over again to do things which the history of cases has demonstrated to ])e impossible. We should know the history of these efforts and failures, and their meaning in pathology. Slowly, possibly very slowly, we will find ways to do things which we can not do now. We should ever be on the watch for improvement, but should be very careful about pinning faith to fancies in the treatment of disease. Histological studies or the peridental membrane. In the years preceding the publication of the American System of Dentistry (1886), there was considerable speculation as to the structure of the peridental membrane. There were, however, no studies of this tissue available which seemed to me to be at all sufficient, or which bore the stamp of real histological work. When I was called upon to write the article on the comentum and peridental membrane, and their diseases, for that publica- tion, I undertook the histological study of these tissues along with other work with which I was unusually busy. When my copy was otherwise ready, I found my studies of the histology CEMENTUM, PERIDENTAL MEMBRANE, ALVEOLAR PROCESS. 31 SO hopelessly behind that I wrote a very short description of some of the principal features, and forwarded my copy to the printer. But others were so far behind in their work that the final completion of the book was much delayed. In the mean- time I had found the facts on which I could have written the histology complete. I was glad to find later that my short and insufficient description of the membrane contained no serious errors. My later studies of the histology of the peridental mem- brane and the comparative study of the periosteum in different parts of the body were embodied in a series of articles published in the Dental Review, beginning witli its first issue in November, 1886, and continuing in 1887 until completed. As soon as tliis publication was completed, the copy was revised and published in book form under the title of ''The Periosteum and Peridental Membrane," 1887. Figures 27 to 42, illustrating the growth of connective tissue, and Figures 47 to 65, illustrating the growth of bone, are reproduced from this book. Very slowly the facts developed in these studies are finding their way into our better text-books, as yet insufficiently stated, but with improvement as the years go by. The very concise statements of the histological structure, with excellent illustrations, by Dr. F. B. Noyes, in his book on dental histology, published in 1912, are assisting mate- rially in spreading correct information. During the past few years, there have been a num]:)er of articles by German scientific observers relative to the cellular elements in the peridental membrane. Many of these have been written by able histologists, and add much of accurate knowledge of these tissues, both in their normal condition and in their pathological changes. Reference will be made to these studies in the consideration of the specialized cells of the peridental membrane and also in cyst formation. The Cementum. ILLUSTRATIONS: FIOUUKS 43-92. The cementum covers the root portion of the tooth, enclos- ing the dentin, and usually slightly overlaps tlie gingival portion of the enamel. The attachment of the peridental membrane is therefore to the cementum. The cementum is a speciali5;od tissue. Nothing like it exists elsewhere in the animal body. It is in every respect a passive tissue. It does not originate any form of physiological activity. 32 SPECIAL DENTAL PATHOLOGY. It does not build itself, nor repair injuries to its own tissue. It is laid down on the dentin by the peridental membrane very much as subperiosteal bone is built by the periosteum. It is much like bone, and has in its substance corpuscles very like the bone corpuscles. Especially, it closely resembles subperiosteal bone in its histological content. But the corpuscles are usually fewer and less regularly placed. In some specimens, however, the cement corj)uscles are plentiful. In this, different specimens vary widely. The cementum is much thicker toward the apex of the root, and thins away toward the gingival line, which it forms by lapping slightly on the margin of the enamel. Differences between cementum and bone. The point in which cementum differs most widely from bone is in the absence of a blood vascular system. In bone every part of the tissue is within the sphere of the circulation of red blood, and, without aid from adjacent tissues, is subject to absorption and perfect rebuilding of its own tissues at any time. It has this power within its own tissue. Also subperiosteal bone is cut away by absorption and rebuilt as Haversian bone, which has numerous channels conveying arteries, veins and nerves.* (See Figures 43, 44, 45 and 46.) Cementum has none of these whatever. It has no circulation of red blood in any form. It is therefore dependent upon the peridental membrane for the maintenance of the life of its cement corpuscles. Cementum does not eepair injuries. Cementum has not in itself any power of repairing injuries to its tissue. When stripped of its peridental membrane it becomes a dead tissue, no matter if the pulp of the tooth is alive. The tissue of the cementum has no power of initiating or carry- ing forward any reparatory process whatever in the absence of the soft tissues around it, or when these have been parted from it by suppuration. Cementum subject to absorption. The otherwise normal cementum is very subject to absorp- tions. These begin upon the outside, next to the peridental membrane, and extend inward or laterally from that beginning. This absorption is the true physiological process of the removal of the roots of the deciduous teeth in the shedding of these in * " The Growth of Bone," by William Macewen, F.R.S., published in Glasgow in 1912, is a splendid work which gives a much broader view of the growth of bone and its powers than it is possible for me to give here. Fig. 47. ■jj^f-/ '^ ^ B ? / JS ^ * ' ^ r It ', ^ (J, - (<<^> ^ Fig. 48. Figs. 47 to G5. A series illiistratiiig the growth of bone. Fig. 47. Non-attached periosteum from the sliaft of the f.'iniir of the kitten. B, Bono, o, Layer of osteoblasts. In tlic central portion of the figure they have been pulled slightly awav from tiie bone, displaying the processes to advantage. It will be observed that the fibers of the periosteum do not enter the bone. a. Inner layer of fine white fibrous tissue (osteog.Mietic layer) showing the nuclei of the fibroblasts and a number of developing connective tissue cells, which probably become osteo- blasts, c, Outer layer, or coarse fibrous layer, in which fusiform fibroblasts arc also rendered apparent by double staining with hematoxylin and carmine, il. S.une remains of the reticular tissue connecting the superimposed tissue with tlie |)cnostcuiii. Fig 48. Attached periosteum from beneath the attachment of tlie muscles of the lower lip of the shee]). a. lione. b. Osteoblasts, with the fibers emerging from the bone between them, c, Inner layer with fibers decussating and joining the inner side of the coarse fibrous layer in opposite directions. This is ratlier an unusual form of this layer of tlio ]ieriost.Mim. p. Coarse, fibrons layer, v.. .XttachmiMit of muscular fibers. *4 . f .IklilllUl Fig. 49. Fig. 50. Figs. 47 to Go. A series illustrating the growth of hone. Fig. 49. Periosteum from the shaft of the tibia of the pig, lengthwise section, showing the complex arrangement of fibers in the coarse or outer fibrous layer which sometimes occurs under muscles that perform sliding movements. B, Bone. 0, Layer of osteoblasts. The tissue has been pulled slightly away f>om the bone in mounting the section, and part of the osteoblasts have clung to tlie bone, some have clung to the tissues, while others are suspended midway, their processes ('linging to each, a, Thayer of fine fibers. Inner or ostcogenetic layer of the periosteum, b, First lamella of the coarse or outer fibrous layer, the fibers of which are, in this case, circum- ferential, exposing the cut ends. It will be observed that there are ten lamella; in the make-iiji ni' tlie outer layer, the lengthwise and circumferential fibers alternating. Those marked f, ;iiid i, arc very delicate ribbon-like forms, whicdi liave shifted from their normal position in the mounting of the section, so as to present their sides to view instead of their ends, thus displaying their structure to advantage. The illus- tration shows how readily separable these lamella? are. 1, Reticular tissue. Fig. 50. Periosteum from the lower end of the femur of the kitten at a point where the enlarged end next the joint is being trimmed down for the elongation of the shaft, showing the fiVjers of the periosteum included in. or entering the bone, form- ing its attachment, also the absence of osteoblasts and the presence of osteoclasts by which the outer portions of the bone are Ijeing removed. I3. Bone, c, Osteogenetic, or inner layer of periosteum, d. Outer layer, a part of which seems to have been torn away. E, A few circumferential fibers, f. f, f. Osteoblasts lying in the lacunse of Howship, or exca\!ition« in tlie Imne made bj' these cells. / 1 » . ' , y' I P ^ '>^ * S- •*" f ^ "> '/ /' ^ Fig. 51. Fig. 52. Figs. 47 to 65. A series illustrating the growth of boue. Fig 11 The more usual form of the attached periosteum A, ^""''•. ^' ';;"^ the i^^u^l-fibel: (penetrating tibers of ^^^^^ ^"^^ ^^ZX ^ ' out between the osteoblasts b, an.l breaking up into f '^f^ ';^5;.;, '\ , b"okon margins layer of the periosteum. These are also seen l'^"ti"f "S/'"'",/. "^^ ^ccur mosth in of^he section at g, g, g. d, Blood vessels winch are cut a« -s Phej cu no t .v^^^^ the inner layer, veiy close to the under side ot the «^^' '^ \\;^,/\',,, Haversian bundles. F, Attachment of muscular fibers. ^^ lU b n t .u canals at h, h, h, h. nnd nt nth.'r i-unts, are filling u,. u.th h-.m residual fibers. Fig. 52. A iiliotinnicrograph of an alt;i<-lie ^. Fig. 53. Ck_ "W ^', V>'^ Fig. 54. Figs. 47 to 65. A series illustrating the growth of bone. Fig. 53. Bone, with portion of inner layer of attached periosteum, and pene- trating fibers. The section is cut across the Haversian canals, and it shows the manner of the formation of these in the surface of the growing bone at a, a, by the upward growth of spicula^ of bone which then spread out and join with others, thus bridging over and forming canals. At b, b, b, b, four Haversian canals are seen lined with osteoblasts. Around each of these, fresh bone is being deposited, which may be recognized by a slight difference in shade, but especially by the fact that the bone corpuscles lie in a difrcrent position from others in their neighborhood, and the fact that this bone has no residual fibers. It should be noted that this fonnation of canals immensely increases the area upon which osteoblasts may build. Fig. 54. Bone, with a more solid growth of surface, and with osteoblasts much crowded between the fillers of the periosteum as they emerge from the bone. Only a ])art of the inner layer of periosteum is shown, a, a, Osteoblasts several layers deej) between the fibers of the ]ieri()steum. b. b, S])iculir of bone growing uji into the periosteum, apparently following the line of a particular fiber, c, Haversian canal that seems to have been excavated in the bone, and is Ix'ing filled by deposit of new bone on its walls. This new deposit of bone is distinguished by a somewhat lighter shade, and the difference in the direction of the long axis of the bone corpuscles, and the absence of residual fibers. Osteoblasts appear in this portion of the canal. The margins of the secondary formation show the bay-like forms usual in the absorption of bone. Above the line drawn at E, no secondary bone is found, and osteoclasts, g, g. are seen instead of osteoblasts. In this portion the excavation is going on. In this way the bone, with residual fibers, is removed and bone deposited in which these do not appear. 'I , Fig. 55. ', -'f S^:^ -^f:"^ ^^^m^ Fig. 56. Figs. 47 to 65. A series illustrating tlie growth of bone. Fig 55 Margin of growing bone upon whieli the osteoblasts are very mucli crowdecL a.' Osteoblasts reaching to the surface of the bone by extemliug proccss_ like i.roh.ngations. b, A cell that seems to be flattening down upon the surface of the bono, c, Bone corpuscles, the processes of which are seen ra.luit.ng in the bone matrix. Processes are also seen extending into the l)one from some of the osteoblasts. Fig 56. Cross section of a young growing bone, showing the Haversian canals and the plan of their subperiosteal formation, a, Outer layer of periosteum, b, inner layer of periosteum, c, c, Spicula> of bone growing outward into the tissue ot the inner layer of periosteum, d, Other and older spicula- spreading out at their summits, fr,rming i.ortions of arches, e. Other spieuUv, the arches of which :.re about closing to form Haversian canals, f. Complete Haversian canals, many of which are so.-n in the illustration. ^ir^ 2''^\ Fig. 57. Fig. 58. Figs. 47 to 65. A series illustratiug the growth of bone. Fig. 57. Absorption of bone under attached periosteum, a, a, Osteoclasts lying in deep excavations in the surface of the bone, b, b. Surface of l)one, showing the fibers of the periosteuni implanted in it. Eesidual fiber.s appear in the bone. It will be noted that these fibers are removed with the bone by the absorptive process, c, c, Masses of embryonic tis.sue filling the areas formed by the absorption. Fig. 58. Intra-membranous formation of bone. An island of bony deposit, a, a, Bone corpuscles. 1), b, Osteoblasts. It will be seen that these lie between the fibers of the membrane, so that in certain positions the osteoblasts lie with their ends to the forming bone. For the most part the long axes of the bone corpuscles have a siniilar direction. 'f.^.ff v^ ^ ) • i. " ''' ' -' ^X. «/ .\<'^,-^(. . 111? H flu i ?l!f ; ^'iiiilt Fig. 59. <^ ■ -./ Figs. 47 to 65. A series illustrating the growth of bone. Fig. 59. Growth of bone under the attachment of the Tendo Aehillis in a young lamb. A, Fibers ff& tendon partially converted into fibro-cartilage. The cartihage cells are seen mostly between the tendon fibers. B, b, and c, e, c, Canals advancing from the bone beneath into the tendon, d, d, d, Bone deposited upon the walls of the canals forming Haversian systems laid upon, or among the tendon fibers. E, Portions of the tendon fibers still remaining deep among the Haversian systems of bone. Fig. 60. A, Single canal as shown at b, Fig. 59, very much enlarged, a, a, Car- tilage, b, b, Tissue of canal, c, Blood vessel, d, d, Bone, e, e, Osteoblasts, f, f, Chondroclasts. Tn both these figures the bay-like excavations of the absorption cells are seen in the caTials, iind at the margins of the bone deposited in these. . ■rtoa>'.«^ ^'' **' **' » FiQ. 61. Figs. 47 to 65. A series illustrating the growth of bone. Fig. 61. The changes Avhich occur in diaphysial intra-cartilaginous formation of bone, a, Cartilage nnciiaiigod. At b, the colls have become smaller and have fallen into rows. At c, the cells are enlarged in their short diameters, or in the direction of the length of the shaft of the bone. At n, the growth of tiie cells has reached its limit. The matrix begins to calcify. At E. the capsules of the cells are opened by the advance of the absorbent tissue, f, Area of tlie formation of bone, g, Appar- ently some glutinous remains of the cell body clinging to the walls of the capsule, h, Small round marrow cells, p, p. p. Remains of tlie cartilage matrix, j, Osteo- blasts applied to the remains of cartilage matrix, but no bone is seen. K, K, K, Osteo- blasts and a layer of bone deposited on the remains of cartilage matrix, m, m, m, m. Blood vessels, n, Capsule which seems to have been just opened and the marrow cells seen in the act of crowding into it. o. Fusiform cells. Many of these appear in this portion of the figure, and seem jieculiar to this location. it'^^ l.^»K Figs. 47 to 65. A sprirs i I lust rating tlu' yiowtli of hour. Fig. 62. (Vtitral section of the licad, and [.ortioii of tlic shaft, of tlio tibia from young kitten, Hin)\vinfj (liMjiliyKial intra caitiiayinons formation of the bono at d, and the beginninfj of tlie eiJipiiysial at ii. a, ("artilaiiinons iiead of bone, b, b, Periosteum, c, c, Layer of subperiosteal bone, e, Periosteal notcli ; tlie point to which the sub- periosteal formation of bone extends, f, Beginning of change in the cartihige cells where they form rows, g, Line of absorption of the cartilage. At d, the darkened portion reaching up to the line g, shows the portion occupied by the boue marrow, and the light portions the bone formed. Fig. 63. Supplement to Fig. 61. taken from another portion of the section and showing the marrow cells applied closely to the walls of the capsules next to be opened, a. Cartilage, b, Fusifortn cells filling closely the last capsule opened iu that row. c, c, Round, marrow cells filling other (•ai)snles in tin- same manner, d. Unab- sorbed remains of cartilage nmtrix. Fig. 64. Fig. 65. Figs. 47 to 65. A series illustrating tlie growth of bone. Fig. 64. Epipliysial intra -cartil.'igi nous formation of bone fidrii licjul of tibia of young lamb. a. a, Cartilage, the cells of which have fallen into rows, but have become scattered between the letters a, ami b, b. b. b, Haversian canals advanced from the bone into the cartilage. Tt should be noticed that these are lined with chondroclasts where tiie absorption of cartilage is in j)rogress, and with osteoblasts when bone is being de])osited. (". Blood vessels, d, d, d, Bone, which is extended into the cartilage by the filling of the canals formed by absorption as shown at e. Fig. 6"). From a cross section of a rib of a young kitten at a little distance (boneward) from the change from cartilage to bone sliowing the large Haversian canals with the remains of the cartilage matrix enveloped in the bone formed. a, a, a, a, Kemains of cartilage matrix, which, in the figure, is left white, b, b, b, b. Bone deposited on remains of caitilage matrix, ami generally covered with osteo- blasts, but at c, c, c, c, and other points, osteoclasts are quite plentifully distributed. While in one part bone is being deposited, in another it is being removed, and in the end all the cartilage matrix disappears. Fig. 66. Fig. 6(d. A photomicrograph of a portion of the root and ppridpntal iiiftmbranp of a tooth in wiiic'h an absorption iias boon repaired by a new ^irowth of eenientum. D, Dentin, c, C'eiiieiituni. i", Pcrii|<>ntal membrane. R, New cemeiitum built in, in repair of an injury by al)siirptii)ii. Fig. 67. Fig. 67. Photomicrograph of a cross section of tiie root of a tooth in which absorption is in progress, a, Line of absorption, showing the usual notched appear- ance known as the hicuna> of Howship. d. Dentin, c, Cenientum. p, Peridental membrane. The pulp chamber appears in the left-hand part. The dento-ccmental junction ap]>oars between the letters c ancr centnil incisor showing an absorption of a portion of the root. .Specimen from Nuilliui'strrn I'liixci-sity I)i'iit;\l Mii-^cinn. /t*f*Vr-r>*>rr-Sf_<. '^^ »,^ >>'./ ^.-^ ^TrfS.- ^ Fig. 73. •> .>v„j?^.' ■ ^;,. '7" ■■■v. "it.:-*^-^-- ■ / ^.^ <-: V^u Fig. 74. Fl(i. Vo. From a sect ion of a hicu'^iiiil with its aivcolus. sliowiiig a pit-like absorption upon the si ^r r ;, ■ ' -^^— - !? A,', V •■ ■^ ^ V . ■■ V ,•"_ ",•-• '^"^ -, 1 ^# V;,--;'-"^ " _ **■ -.'^' ":>> -V:.: ;■ -A' "^^ #^ /- |p .Mr.--.:,. .-) .: > ^ 1 V •■ .- 4M ^ • , ^^^•VwI^m!^^;^;!^'' V..; ^?^,:^ Fig. 76. Fig. 77. /^ Fig. 78. Fig. 76. Section of cemciitum of pig cut horizontal to and near tiic surface of the root of the tooth siiowiiig cross sections of the inchuled libers, b. Thin margin of section, from wliich the fibers liave fallen out of their alveoli, c, A little thicker portion in which the fibers remain. It will be noticed that from shrinkage the fiber is a little small for its alveolus, so that it is slightly separated from one side, a, Cement corpuscles. Fig. 77. Longitudinal sfction of the cementuui of a pig, showing the included fibers of the peridental membrane, e, Margin of cementum showing fibers passing from the cementum to the peridental membrane, and the layer of cementoblasts with other cells in the neighborhood, f. Epithelial cells, d, d, Fibers protruding from broken margin of section, a. Dentin, b. Junction of dentin and cementum. Fig. 78. Cementum of pig from the dried section, a, Dentin, b, Lacuna? of cementum with canals anastomosing with each other, c. Imperfectly calcified fibers. It will be noticed that a few of the dentinal tubes pass through into the cementum. Fig. 79. F\r,. sil. Fig 79. A transverse section of a root extracted from a young person. The cementum is thin, but is thicker in the groves on the proximal sides, ^oycs Fig. 80. A transverse section of a root fro,n an old person. ^^rZl L'Z' ried a crown for many years. The section was cracl^ <^ -..■-■• 5(^:ii»«?.:^ 1/ ^4' #M^i«i ,l<^ Fig. 81. iV^* iimwimm. -if"' Fig. 82. Fig. 81. Hypertrophy of the cemcntum on the side of the root of a lower molar near the gingival line of the tooth. From a longitudinal section, man. a, Dentin, b, Cementnm. c, Fibers of peridental membrane. From b to c the cementum is normal, and the incremental lines fairly regular, but at d, one of the lamellae is greatly thickened. .At c, tliis lamella is seen to be about equal in thickness with the others. The next two lamella; are thin over the greatest prominence, but one is much thickened at g and both at h. These latter seem to partially fill the valleys which were occasioned by the first irregular growth. Fig. 82. Hypertrophy from ^oot of cuspid, man, in which the irregularity is confined to the first lamella, a, Dentin, b. Thickened first lamella, c. Subsequent lamella-, which are seen to be fairly regular. Fig. 83. Fig. 84. Fig. 8.5. Fig. 8G. Fig. 87, Fig. 83. Apex of root of an upper first bicuspid tooili with irrcguiiirly developed eementum. a, a, Dentin, b, b, Pulp canals. The lamella of cenientuni are marked 1, 2, 3, etc. d, d, d, Absorption areas that have been refilled with cenientuni. It will be seen that the apices of the roots were ori^niially separate, but became fused with the deposit of the second lamella of cenientum, and that in this the irregular growth began and was most pronounced. It has continued through the subsequent lamelhe, but in less degree. Tt will also be noticed that the absorption areas, d, d, d, have proceeded from certain lamella'. Between the roots this has broken through the first lamella and penetrated tlie dentin, and has been filled with the deposit of a second lamella. Other of the absorptions have jiroceeded from lamellsp, which can be readily made out. The small iioints. e, seem to have been filled with the deposit of the last layer of the cenientuin. wliilc oUkm-s have one, two or more layers covering them. Figs. 84, 8.5, 86 and 87. Teeth with extensive hypercemeiitosis. Sp(>ciiiiens from Northwestern University Dental Museum. Tooth shown in Fig. 84 jiresented by Dr. T. A. Black, Galveston, Texas. Teeth shown in Figures sn and 8() jiresented l)y Dr. Amy Bowman, T^os Angeles, California. Fig. 88. Fig. 89. Fig. 90. Fig. 91. Fig. 92. Fics. 88, 89 AND 90. Teeth with roots fused by the coalescence of cementum. Specimens from Northwestern University Dental Museum. FIG.S 91 AND 92 Teeth with roots fused by the coalescence of cementum. Specimens from Northwestern University Dental Museum. Teeth shown an Figure 92 presented by Dr. A. S. Cheeseman. .Toliet, Illinois. n^f at FlO. 93. Fig. 93. Longitudinal bucco-Iingiial section through root of tooth and gingival portion of investing tissue showing fibers of the peridental membrane. E. Epithelium. D, Dentin, c, Cementum. s, Subgingival space. F, Free gingiva? group of fibers. A, Alveolar crest group of fibers, ii, Horizontal group of fibers, b, Bone of alveolar process. Noyes. i<'^ */ pit Fig. 94. Fig. 9.5. Fig. ,)4. Longritn.linal .section, slightly obliquo. through root and noridental membrane, shoAving fibers of the peridental membrane, e, Epithelium, d, Dentin. c, Lementum. s, Subgingival space, f, Free gingiva- group of fibers, a, Alveolar crest group of fibers, h, Horizontal group of fibers, o. o. Oblique group of fibers B, Hone of alveolar process. Fig. 9.5. A higher magnification of a part of Figure 94. THE PERIDENTAL. MEMBRANE. 45 general agreement, viz., that these strings of epithelial cells mul- tiply in the peridental membrane, break up, form sheets of cells which surround certain areas of infection, and cut them off by encysting them. The activities of these cells will be more fully considered under the subject of cyst formation. Physiological Powers of the Peridental Membrane and Cementum, as Shown by Planted Teeth, ILLUSTRATIONS: FIGURES 117-119. The physiological powers of the several elements which com- pose the peridental membrane, their correlation to the cementum in minute anatomy and in function, and especially their power and lack of power to repair themselves and renew their physio- logical connections with their related tissues when injured by disease or accident, are of much more than usual importance.. Dentists have been very slow in gaining an understanding of the peridental membranes and their relations to the tissues with which they are connected, because they have made so little prac- tical study of these tissues. Really they have had but little opportunity to know this subject, since it has been taught very superficially, if at all, in dental schools. In efforts made by the general profession to study the diseases of the peridental mem- brane and cementum, they have disregarded the powers of these tissues, and therefore have failed to gain the most beneficial infonnation. The planting op teeth. The famous surgeon, John Hunter, whose professional activities were around 1750-90, and who seems to have given unusual attention to the teeth, did quite a little in transplanting and implanting teeth. This operation seems to have become quite popular in Europe during the latter part of the centuiy, but soon died away and was lost to sight. It was not, however, original with Hunter. Guerini gives credit to Amboise Pare for having first performed and described this operation. It had been known and practiced and had passed out of use several times before his day. Even after the beginning of the last century, the transplantation of human teeth was practiced in France, and perhaps elsewhere. There was develo]ied a ]irac- tice of transplanting directly from one human mouth to another. The dentist, being applied to for a new tooth, would, after deter- mining what was needed, find some person who was willing to *6 46 SPECIAL DENTAL PATHOLOGY. sell a similar tooth for a price. Or a good careful lady would bring with her a servant girl who would sell one of her teeth. Then the carious tooth would be extracted from the patient and thrown aside. The similar tooth was then removed from the mouth of the person furnishing the tooth for replacement. The tooth was at once transferred to the alveolus, from which the carious tooth had been removed. (See Figure 117.) The practice seems not to have lived very long, nor to have become very general. No careful records of operations of this character seem to have been kept. Neither can we suppose from the writings which have come down to us that the powers of repair in the tissues involved were given careful study. I have been over most of the old writings in the English, German and French languages, and I do not now remember of a single case in which there was an effort to make a close study of this mem- brane, or of its physiological powers. During the century just passed there were occasional revivals of the practice of planting teeth in the sockets from which teeth had been extracted, often using old dried teeth for the purpose. These efforts were usually individual in character in that they were confined to a few persons. In more recent years, the practice has been revived on the assumption that by the use of antiseptics, lasting operations both in transplantation and implantation might be made. A good many operations were made and attracted considerable attention at dental society meetings, but as time wore on it was found that these operations failed after a few years, the same as others had done. However, with the more careful following of cases which had become possible, the advisability of this operation in individual cases was better studied. The result has been that a few opera- tors have made the most possible of its use in carefully selected cases. So far as I have knowledge, transplantations from per- son to person have not been made in recent years, except by a very few practitioners. During the revival of this procedure, a nomenclature became fairly established representing the different classes of planting operations. Replantation is used when teeth are extracted purposely or by accident, and replaced in their own sockets. Trayisplantation is used when a stranger tooth is placed in the socket of a tooth just removed. •PERIDENTAL MEMBRANE PHYSICAL POWERS. 47 Implantation is used when the teeth have been removed at some former time and a new socket is cut in the residual alveolar process, or ridge, and a stranger tooth planted in it. Taking the mass of evidence afforded by the history of planted teeth, there has been every degree of success and failure which seems possible. A study of these successes and failures illustrates the physiological powers of the tissues to make repairs when the peridental membrane and the cementum have been separated from any cause, or when the wound made by the extraction has healed and all vestige of a peridental membrane has disappeared. The lesson thus learned of the powers of the tissues under such conditions is the all important thing for which this recitation is made. A considerable number of cases were failures from the start. Suppuration occurred in the socket about the tooth, and it had to be removed within a few days or weeks. It seems to have been suflSciently demonstrated that no attachment would be made in areas of suppuration. Often there will be some suppuration about the gingival margin of otherwise successful cases. My personal observation is that the soft tissue never becomes attached over such areas, and the gum quickly shrinks away, leaving some portion of the root bare. In other cases the soft tissues heal about the teeth, and they become tight or fixed immovably in the sockets. These teeth, which seem to present the most perfect condition, are usually lost within one, two or three years, by absorption of the root. (See Figures 118 and 119.) If such a tooth remains useful for five years, it is regarded as a first-class result. No HISTO-PATHOLOGICAL STUDIES OF PLANTED TEETH. Nothlug is yet very certainly known of the histo-pathology in these cases. A number of the remains of absorbed roots have been cut for microscopic study, but these have given little information. I do not now remember of any case in which the root of the tooth, with its soft tissue and bony investments as it was in tlie ,iaw, has been prepared for the microscope and studied ])y a compe- tent observer. Therefore, we are yet without definite informa- tion from the histological standpoint as to what occurs either as the tooth becomes tight, the tissue by which it is held, or the process of absorption l^y which it is removed. In reciting this history T have had no intention of describing in detail the several operations of planting teeth. My purpose has been to illustrate a principle in the coordinate physiology controlling the relations of the cementum and the peridental 48 SPECIAL DENTAL PATHOLOGY. membranes. Particular note should be made of the fact that in some of these operations, old dried teeth, which had been out of the mouth a long time, have been selected for planting. These seem to have done about as well as comparatively fresh teeth, but not so well as teeth which were removed or displaced by accident, and in which the same tooth was immediately replaced into its own socket. It has been said that John Hunter, whom I have mentioned, had at one time several roosters about his yard with two or more human teeth planted successfully in their combs. Also that an enthusiastic Frenchman succeeded in planting a human tooth in the forehead of a rat, and it became firmly fixed to the skull. I will not vouch for the correctness of either of these stories, but from that which I have myself seen, I believe both are possible. Chemotaxis. The meaning of the above line of facts is that there exists between the soft tissue cells, or some of them, and the cementum covering the roots of the teeth, or even the dentin itself, a positive cliemotaxis which causes the soft tissue cells to seek, or to approach, the cementum, to develop in contact with it and attempt to make an attachment. The principle in nature expressed by this word chemotaxis (Chemo — Chemistry, and taxis — orderly, or in an orderly way) has assumed great importance within recent years in physiology, pathology, bacteriology and immunity from, or susceptibility to, infections and infectious diseases. It serves to explain many things which previously seemed incomprehensible. The Standard Dictionary gives the following definition: ' ' Chemotaxis : The property which certain living motil cells possess of approaching (positive chemotaxis) or moving away from (negative cliemotaxis) chemical substances of various kinds. Chemotaxis seems to play an important part in some phases of inflammation. Thus it appears to be, in part at least, through the incitement of chemotaxis by the chemical substances which they contain or eliminate, that bacteria act in producing suppuration." Stedman's Medical Dictionary gives the following defini- tion : ' ' Chemotaxis : Reaction of living protoplasm to a chemical stimulus wiiereby the cells are attracted (positive chemotaxis) or repelled (negative chemotaxis) by acids, alkalies or other bodies exhibiting chemical properties." It is through the principle expressed in these definitions that many of the physiological and pathological reactions occurring PERIDENTAL MEMBEANE PHYSICAL POWERS. 49 between tissues of different kinds are brought about. It seems also that it is a principle which is often active in infective inva- sions of micro-organisms, or in preventing such invasions, and thus bringing about conditions of susceptibility or of immunity. On the basis of a positive chemotaxis, we may explain a fact that is sufficiently apparent in the line of experiment recited. AVhen a tooth, which has been extracted for some time, is planted in the tissues of the jaws, whether in a previously existing socket of a tooth or a socket cut for it, under conditions fairly favorable to the healthful action of the soft tissue elements of the neigh- borhood, there is an immediate tendency for the cellular ele- ments, or certain of them, to attach themselves to the root of the tooth and develop there into fixed tissue. In this way they form an attachment to cementum, or even to dentin. A growth occurs that we may suppose endeavors to reform, or to form an ordi- nary peridental membrane. It is more probable that the tissues act much in the same way in which open wounds heal by the formation of cicatricial tissue. As the peridental membrane is a specialized tissue, having in its make-up several kinds of cellular elements and of fibers specially arranged for the performancec of its special functions, we must suppose, from the uniform disastrous results which follow all forms of planting teeth, that at least some parts of these have failed, if indeed there is any definite attempt to reform them. Therefore the connection is physiologically unsta- ble. For this reason the absorptive process begins in the root and continues more or less rapidly until the tooth is cast off. Attachment or planted teeth physiologically unstable. The absorption of the root is the universal result of all kinds of planting of teeth in the jaws. The history, therefore, shows conclusively that the attachment is physiologically unstable. It shows further, that positive chemotaxis is changed to negative chemotaxis whenever the root of the tooth, or some portion of it, has been exposed to suppuration and has presumably absorbed products of suppurative decomposition. If we comi)are the con- ditions of the peridental membrane and the cementum in cases of replantation and in cases where pockets have formed beside the roots of teeth, we find the conditions so similar that we may well regard them as the same. With the suppuration which has occurred and the loosening of the soft tissues, we must suppose that the integrity of the peridental membrane, as such, and of its special elements which fit it for the performance of its functions, 50 SPECIAL DENTAL PATHOLOGY. have been destroyed, and that the tissue in its place is ordinary gingival or gum tissue, which has been modified and weakened by repeated inflammations and suppurations. Over against this is a cementum that has lost its positive chemotactic qualities by having absorbed the products of suppuration. To cap the climax of disabilities present in these cases, they are placed in a field constantly exposed to active infective elements, and are con- stantly being reinfected. The conditions are such that these reinfections are not preventable. When we compare the above with a fresh wound created by forming a new socket in the residual alveolar process, or by clearing a socket where a tooth has somewhat recently been extracted, we will see at once that the condition of the tissue in a socket so prepared for the reception of an implantation is in better condition to invite an adhesion of soft tissue than in any case in which the tissue has been detached by an infection along- side a root. Under all of these adverse conditions, how shall we expect pockets to heal, reattachment of the soft tissues to the cementum to occur, and permanent cures of this condition to be made? As a matter of fact, such cures do not occur, nothwithstanding the reports of successes. As I must acknowledge that in the past I was for a consid- erable time deceived by the appearance of betterment which followed treatment, and supposed and stated, as will be found in the article I prepared for the American System of Dentistry, that actual cures occurred under these conditions, the above statement should not be taken as offensive by any one now in practice. The Alveolar Processes. ILLUSTRATIONS: FIGURES 120121. The alveolar process is the projection of bone which grows up around the roots of the teeth, and forms the sockets in which the roots of the teeth are held by their membranes. These sockets are the alveoli of the teeth, or if we speak in the singular, each socket is the alveolus of a tooth. The word alveolus means a hole. The alveolar process is the wall of bone around the hole. This is not a separate piece of bone but is con- tinuous without demarcation with the bones which form the maxillcT. There seems to have been no rule among writers on dental subjects as to the use of the singular and plural forms, alveolar process and alveolar processes. THE AL^T<:OLAE PROCESSES. 51 The peridental membrane, as united to the cementum on the one side and to the alveolar wall on the other, connects and binds together the root of the tooth and its alveolar process, thus hold- ing the tooth in position. (See Figures 97 and 98.) Really there is but a single alveolar process in each jaw, which passes around the arch in a single bony projection in which there are the number of alveoli for the accommodation of the roots of the teeth. In most cases the projection of the alveolar process above the body of the bone is not sufficient to accommodate the full length of the roots of the teeth, and the alveoli are sunk into the body of the bone so far as may be necessary. The alveolar process does not quite cover the gingival portion of the cementum, but stops about two millimeters short of the gingival line of the tooth, different specimens varying somewhat from this measurement. The crest of the alveolar process is therefore always lower than the gingival lines of the teeth. The alveolae processes are bone. The alveolar processes are bone, pure and simple, with all of the endowments of the bones in general. Their blood supply is richer than that of most bones, their Haversian canals are larger, and the amount of blood passing through them is greater than in the bones in general. The nerve supply is also richer. To accommodate this very rich circulation, the alveolar pro- cesses are permeated by many Haversian canals and a large number of these pass through directly or indirectly from the side of the mucous membrane to the side of the peridental membrane, or the reverse, giving to the peridental membranes a rich collat- eral circulation through the alveolar wall. Wherever the bone constituting the alveolar wall is con- siderably thickened, it has a fairly solid cortical, or surface por- tion, toward the mucous membrane side, and a thinner, fairly solid portion on the side next to the peridental membrane. In the central portion between these two, the bone is much less dense. Indeed, wherever there is thickness enough to ]^ermit it, it becomes cancellous or medullary. It is divided in many direc- tions with thin laminae of bone, uniting the whole together in a strong mass, in which the interspaces are filled with connective tissue, blood vessels and nerves, giving it a physiological activity closely related to the ordinary connective tissues. The alveolar process rises much higher above the true form of the maxillary l)ones in the front ])art tlian it does in the back 52 SPECIAL. DENTAL PATHOLOGY. part of the mouth. It is therefore higher about the incisors and cuspids and lowers away toward the back part of the mouth until, in the lower jaw particularly, the alveoli for the second and third molars are often hollowed out in the body of the bone. Indeed in many cases the alveolar walls on the lingual sides of these teeth are built out around them as they lie one-half, more or less, out on the lingual side of the bone. In the upper jaw a much more decisive alveolar ridge is maintained even to the third molars, but this part of the ridge is much lower than in front. Development of the alveolar processes. One who has followed carefully the development of the teeth and the dental arches in the clinical way, together with the occlusion of the teeth, in many children, and the malocclusions which occur among them, will have discovered that the teeth are not made to fit their alveoli, but that the alveoli are made to fit the teeth. The teeth, during the development of the arches, go on with their movements as the bones of the face are growing and expanding from the face of the child to the face of the adult. The teeth are assuming the adult positions by which they are assisting in rounding out the prominences of the adult features. During this time the alveolar processes are keeping even pace with the movements of the teeth. As the teeth move forward, the alveolar walls are absorbed here and built out there, to accommodate the movement. (See Figures 120 and 121.) If some one or more of the teeth are taking wrong positions, bringing about malocclusions, they are not lim- ited or perceptibly held back by their alveoli; but the alveolar walls will be changed in form and built to fit the teeth in the mal- position. A cuspid tooth that is crowded forward out of its normal position, for instance, has the walls of its alveolus changed to accommodate this movement. It is not crowded out of its alveolus. It does not lose the fitting of an alveolar wall around it because the tooth has taken a wrong position. This exhibits in i)art the related physiological factors existing between alveolar processes and teeth and the bones of the face. All of this goes to show that in the related physiological factors between the positions of the teeth in the arch and the formation of the walls of their alveoli, the teeth are accommo- dated by the growth of bone about them, and are given the sup- port that the performance of their functions demands. Even if there are supernumerary teeth, not usually reckoned with as normal, their alveolar process is built about them in any position '' % Pig. 96. Fig 96 Drawing representing a longitudinal section, to illustrate the fan- shaped fibers. It is almost impossible to get an actual section through the tissues which shows the arrangement, on account of the interlacing of tlic various bundles of fibers. Fig. 97. Fig. 97. Transverse section of the peridental membrane in the occlusal third of the alveolar portion (from sheep), m. Muscle fibers, per. Periosteum. a1, Bone of the alveolar process. Pd, Peridental membrane fibers, p, Pulp. D, Dentin, cm, Cementuni. Noyes. Fig. 98. Fig. 98. Cross section of the root of a tomporary incisor with the pendentil membrane and alveolar walls, at about the middle of the lower third of body of the peridental meinbrane, showing the direction of the fibers of the membrane, and the position of the blood vessels, a, The dentin, b, Cementiiin. c. Pulp. Its blood vessels are shown, d, d, Alveolar wall, septi between the teeth, e. (-.Peridental membrane. The direction and arrangement of its fibers have been ("arefvdly repre- sented; also the position and relative size of its blood vessels, f, Thiu portion of the anterior alveolar wall, g, Hypertrophy of the cementum. (r'^-^^^-^'^-r^ FiQ. 99. ^;^,j^^;j\v^^-^^^\^>^?^?J^^ Fro. 101. Fig. 99. Fibers of the peridental iiienibrane passing from the cementiim a, to the alveolar wall b. The section is from tlie root of a first molar of a man about seventy years old. The point eliosen for tliis illustration includes a portion of a strong band of solid fibers c, which pass unbroken from the eementum to the bone. More generally, the fibers, after emerging from the eementum, break up into finer fibers or fasciculi, as at d. This form of the fibers is better shown in Fig. 100. Fig. 100. Fibers emerging from the eementum and breaking up into fasciculi. From the peridental membrane of a molar of an aged person. This represents the more usual form of the principal fibers, as seen in old age in man. They pursue a somewhat wavy course, and generally the identity of the individual fiber is lost. They are inserted into the bone in compact bundles similar to those of the eementum. Fig. 101. A group of fibers emerging from the eementum near the apex of a root and radiating fandike. On either side, the principal fibers are absent for a little space, which is filled with indifferent tissue. From the apical space of a bicuspid of an old person. Fig. 102. Fig. 102. The gnathodynaniometcr, about tAvo-thirds natural size. Face view. c, c, The rubber pads bitten 'upon in determininp: the ]>ressure of the teeth, d. Scale of pounds. E. Needle Avhich marks tlie pounds. In use this needle riMiiaiiis stntionary at the highest point reached until it is moved by the iingers. Fig. ]03. Tig. 104. Fig. 103. Fibers and fil)rol)lastH from transversp section of membrane: F, Fibers cut transversely. f1. Fibers cut lonfrituilinally. showing fibroblasts. Noye.t. Fig. 104. Peridental membrane from perpendifular section of a tooth of the pig, stained with nucleus tinting stain, a, f'ementum. li, Bone, c, Blood vessels cut diagonally, d. Nerve bundle, e. Epithelial cells. A number of strings and clusters of these are seen near the cemer.tum. The principal fibers are transparent, while the interfibrous tissue is stained. The cellular elements appear in rows between the principal fillers, which are large and strong near the bone, ami only partially break up into fascicidi in the central part of their length. PdM rd F. HE Fig. U).-j Fig. 10.5. Pcnotratirifr fibois in bono, ivl m. Peridental membmne. obt, Osteo- blasts of peridental nionibrane. ob2. Osteoblasts of medullary space, pd B, Solid subperidental and subperiosteal bone with imbedded fibers, ms, Medullary space formed by absorption of tlie solid subperidental bone witli imbedded fibers, n, B, Haversian system bone without fibers l)uilt around the medullary space. Noycs. Fig. 106. ft- -^\-^. ^ -%. *^ Fig. 107. Fig. lilt). From scctimi iii'-luclin^ ;i |Hiili(in ut' the ;tl\<'nl;ir w.'ill. ;iiicl portions of tlio pciidoiital incmhnmi', sliowiiij; tl stcohhists. ;i. lionc. iiiiior iiuirj^in of alveolar wall, sliowiiifj residual fillers. h. Osteoblasts. Developing eells are seen in the neigliliorliood. e. Fibers of tlH> peridental membrane. It will be noted that these spring from the bone as solid fibers and immediatcdy break up into fasciculi. Fig. 107. From section including a portion of the alveolar wall, and fibers of the peridental inendirane at a ]>oint where these latter are large and compact, and with interfibrous tissue between them, a. Bone showing the large residual fibers, b. Osteoblasts filling spaces between the fibers, c. Principal fibers of peridental niendjrane, which at this point maintain the solid form far out from the bone, d. Interfibrous tissue consisting of fibroblasts and fibers which lie between the prin- cipal fibers and TMirsue an indejiendent course. ('ompan> with Fig. lOG. I'lCj. 1 !.•><. Fig ins 'rransversc soction, shuwiiig llu' cvUnUv flci.uMits. Kb. Fil)n)hlasts. EC, Epithcliai structures, cb, Cenientoblasts. cm, ConuMitum. d. Dnitin. ^oyes. Fig. 109. Fig. 110. ^^i^r*v. ■.. --^i? S^S^?44;w'-" (/UO Fig. 111. Fig. 109. (,'oiiu'iitiiiii and portion of tlio peridental membrane from tho sheep. From a cross section of the tooth, a, ("ementum. B, Cetnentoblasts lying between the fibers, which later break up into fasciculi immediately after leaving the cementum. c, e, Cross section of epithelial clusters, d. Fibroblasts, k, Blood vessels. These are accompanied by a large amount of intor-Jibrous, or indifferent connective tissue. F, Nerve bundle, fi. Fasciculi of fibers pursuing a direction different from the main trend of the principal fibers. Fig. 110. Cementoblasts isolated to show the ]>cculiar irregular forms of these cells. Fig. 111. Cementoblasts, in situ, with cross sections of the pi'incipal fibers of the peridental mendirane of the pig, from a section cut horizontal to the surface of the cementum and including these cells. It will be seen that the cementoblasts fill all the space not occupied by the principal fibers. THE ALVEOLAR PEOCESSES. 53 they may take. It is interesting to follow these movements and the actions and reactions of the tissues in their natural physio- logical dependence upon each other and to recognize the forces at work. When the teeth are malposed. When teeth are in malpositions from some cause, and the proper devices are used to direct the teeth back into normal posi- tion — or better said, to stimulate the growth of the bones in such directions as to bring the features to the normal fomi and allow the teeth to come into proper positions, the walls of the alveoli about the teeth will grow the changes to accommodate the movement. In cases in which supernumerary teeth have diverted one or more teeth from their nonnal positions, they will come to their normal positions soon after the supernumerary teeth are removed ; or if the cuspids have not fully erupted on account of lack of space, they will move into place if the proper space is made for them. When we have learned the nature of these physiological rela- tions of teeth, their alveoli and the bones which form them, and these forces are gently stimulated and directed, they do our bidding. This, taken as a whole, represents very briefly the physiological relations of the teeth and the growth of the bones of the face in which the alveoli and the alveolar process are active participants. When teeth are extracted. Finally, if further evidence were needed to show that the alveolar process is the physiological servant of its related tissues, and especially of the teeth, the results which occur when the teeth are lost may be cited. Straightway the alveoli are in part filled with a new growth of bone and the prominences of the alveolar walls are removed by absorption. Then a residual alveolar ridge is all that is left. In this there is no trace of the former alveoli. The gingivae which rested upon the crest of the alveolar process, with all of their appendages, are gone. The conditions of the formation of this residual alveolar ridge, the influences which give good form and which give bad form, are very important. They are discussed elsewhere. Results of a break in the PERroENTAL membrane. Another point of im])ortance that we should know early in our study of pathology is that there will I'emain no alveolar ♦7 54 SPECIAL DENTAL, PATHOLOGY. process over any part of the root of a tooth without a peridental membrane. The peridental membrane makes the connection between the tooth and the alveolar process, and when this is broken in any part it is as if the tooth were lost, so far as that particular part of the alveolar process is concerned. Straight- way this portion of the alveolar process is absorbed and removed. Movement of teeth subsequent to extractions. Another action which often does almost incalculable harm is apt to follow the extraction of any one of the teeth. Suppose, for instance, that a first molar is extracted when the person is twenty years old and the formation of the arches is practically completed. The socket of this tooth, which is the broadest in the mouth in the mesio-distal direction, is quickly filled in with bone, and its prominences, with the gingivae which rested upon them, are removed by absorption. In the gum tissue which covers this, a hard, dense cicatrix is formed. The fibers of the peridental membrane, which formerly passed from tooth to tooth over the crests of the alveolar septal processes, and which have been torn across about midway between the two teeth both to the mesial and distal of the extracted one, are then attached to this cicatri- cial tissue. This shrinks very materially as the rule. This shrinkage, with the pull of the trans-septal group of fibers, tends to drag the second and third molars forward, causing them to lean over to the mesial, so that their occlusal surfaces do not meet the opposite teeth properly. The bicuspids may be simi- larly drawn distally. The result is bad occlusion of these teeth, which is liable to lead to their loss some time in the future by inducing disease, because of the derangement of contact points. THE SALIVA. THE SALIVA The saliva is a mixed fluid, the most important constituents of which are ptyalin, mucus, albumin and water in variable amounts, containing in solution the following salts : potassium and sodium chloride, potassium sulphate, sodium carbonate and calcium carbonate and phosphate. Certain others are frequent constituents, but not always present in appreciable quantities. Several of these constituents may be present, or absent; these may assume some importance in general descriptions. The presence of potassium sulphocyanide has given rise to a good deal of discussion in connection with the study of immunity to dental caries. The following data will give a better view of the constituents of saliva :* Water 994.203 Solids : Mucin and epithelial cells 2.202 Ptyalin and albumin 1.390 Inorganic Salts 2.205 5.797 1.000.000 (Potassium sulphocyanide 0.041.) It might be said, then, that the saliva consists of water, in which there are suspended ptyalin, mucus, albumin and the salts which are mentioned above, and any one of them may be abundant or scant. The amount of these constituents is very variable. I shall not in the present writing undertake any extended nor very critical description of the saliva, neither of the mixed fluids nor of its constituents, but sliall give only an outline of these fluids as they are observed in the mouth in tlie practice of dentistry. The composition of the saliva is very comi)lex, as will be seen from the table, but really it is very much more complex than the table would indicate, by reason of its great variability. Some specimens of saliva are very mucilaginous, others are very thin and waterj^ Certain specimens seem to liave large * American Text-Bonk of Pliyaiologry. Win. IT. TTowoII. 56 SPECIAL DENTAL PATHOLOGY. amounts of albumin, others seem to be almost destitute of albu- min. The albumin, mucus and other similar substances are known as the colloids of the saliva. In most specimens of saliva, scattering spherules may be found which have generally been spoken of as salivary corpuscles. In some specimens these are very abundant. These will be discussed a little later. The loading of the saliva with carbon dioxid is practically continuous, and there are some other gases generally present in the fluid. Indeed, from the fact that car1)on dioxid is pro- duced in the blood and tissue juices in the metabolism going on in the body, and is excreted mostly by the lungs, it will be seen that this amount will be variable within certain limits, but that the gas will also be present in the secretions and excretions. The saliva always contains a variable proportion of this gas, which may be removed from it by reducing the atmospheric pressure on the liquid by the use of an air pump, and its quan- tity may be determined. The relative quantity of the other constituents of the saliva may be detennined by chemical processes. For a full description of the saliva constituents, I would recommend the student to works on physiology, and especially the American Text-Book of Physiology, edited by Prof. win. H. Howell, Ph.D., M.D. This statement, with a gen- eral reading of one or two recent books upon physiologj^, in which studies of this subject are given in extenso, will prepare a student for special observations which I shall detail here. Ptyalin. Ptyalin is a digestive body found in the saliva. It is an unorganized, ferment body, or enzyme of the amylolytic type, which induces a peculiar action in starch, converting it into sugar. This action is produced very quickly in cooked starch, but in raw starch is so slow as not to be appreciable in the ordi- nary chewing of food. The effect of cooking upon starch is to break the membrane of the starch granule and expose the starch innnediately to the action of ptyalin; while in raw starch the granule is surrounded by a membrane of cellulose, which pre- vents the ready action of the ptyalin upon the starch enclosed. Hence, much greater time is required for the digestion of raw starch. The action of the ptyalin of the saliva upon cooked starch is so prompt that it may be readily appreciated by taking a piece of ordinary bread in the mouth and chewing it. In the first acts of chewing this bread (taking no water), it will be Fig. 112. Fig. 112. A section outliiifr diagonally through the root. A, Network of epithelial cords; D, dentin; cm, ccmentum. Noyes. Fig. 11.3. Fig. 114. x: Fig. 115. Fig. 113. Strings of epithelial cells from peridental membrane. From a sec- tion taken horizontal to the surface of the cement urn, hut a verv slight distance from it. Cross cuts of these are seen at c, c. in Fiyuic 1(1!). Fig. 114. Transverse section of tiic pciidcnlal mciiiliraiic in the gingival por- tion, showing the position of the eiiitlidial cuds. 'I'lir loop at A is shown more liighly magnified in Fig. 116. Noticti. Fig. 115. Epithelial cells from near tlie gingival border of the peridental membrane, a, a, a, Individual epithelial cells, b, b, Caj)illary vessel. Fm. 116. Fig. llli. Kpitlirliiil stnictnres: v.c. K|.itlii'li;i hiinen. cb, Coinciitohlasts. cm, (Viiu'iitmii. n. Dnitiii Noyes. iiiii. :i|i|),i liMil ly sliiiwiiii; :i 'liis Idiip is sct'ii ill Fi^r. 114. Fig. 117. Fig. 117. A famous dental cartoon, of Rowlandson, published in 1787, depict- ing the operation of transplanting teeth from the mouths of the poor to those of the wealthy. This operation was made popular by the publication in 1778 of the work of Sir John Hunter, entitled '"A Practical Treatise on the Diseases of the Teeth," in which he describes the operation. Acconling to the historian Guerini, Abulcasis, an Arabian, 1050-1122, first men- tioned replantation, but to Andjoisc Pare, 1517-1592, credit should be given for having first jKn-formed and described the operation of transplantation. Original of this illustration in Xorthwe^tcni riiivorsity Dental Museum. Fig. 118. Fig. 119. Fig lis K,.i,r.Hl.i<-ticui uf -a radiuyntph of i.n i.]'!"''- '•<-"tr:il uu-isor implanted bv Dr Thomas L. GilnuT. Wl,..., this ra.li..Kraph was taken the tooth ha.l l.oon in the alveolus nearly three years. It Avill be noticed that the tooth ha.l been cut away by absorption from either side almost to the root filling. Fig 119 A bicuspid tooth which wis implanted ami remained in the alveolus about tiiree vears. The extensive absorption of the root is very .dearly shown. Specimen fro'm Northwestern University Dental Museum. / ';:^ '' Fig. 121. Fig. 120. Portion of the labial alveolar wall of an incisor that is being absorbed, a, a, Portion of the inner layer of the periosteum, b, b, Bone forming a jiortion of the labial wall of the alveolus. It will be observed that it contains a number of Haversian canals, h, h. c, c, A portion of the peridental membrane, d, d, d, Osteo- clasts which are in the act of removing the bone, thus widening the alveolus, e, Space from which a largo osteoclast has probably fallen during the preparation of the sec- tion. It will be noticed that wliere the osteoclasts are removing the bone, the fibers of the peridental membrane are detached and some little space is occupied by tissue of embryonal type, but in the spaces between the groups of osteoclasts the fibers are firmly attached to the bone. At f, there seems to be a little new bone formed to which fibers are attached. In this way bone seems to lie removed, part by part, and the attachment of the membrane maintained. Fig. 121. Portion of the alveolar wall of a cuspid tooth of an old person, show- ing absorptions, a, a, Portion of the peridental membrane, b, b, Portion of bone that seems to have been built on to supply an area of previous absorption, e, A recent absorption area. At f, three osteoclasts are seen. It will be noted that the fibers of the peridental membrane are detached throughout this area of absorption and the space is occupied by tissue of embryonic type. It should also be noted that the Haversian systems of the bone had been cut into by the previous absorption, removing portions of the rings of the Haversian systems. Residual fibers are seen in the bone b. but there are none in the Haversian bone c. THE SALIVA. 57 noted that it is moistened by the saliva. In a very short time, the chewing proceeding, a sweetish taste will be noted, and pro- ceeding further with the chewing, until the bread is converted into a pulp, this sweet taste becomes a prominent feature. This is the result of the conversion of the starch into sugar by the ptyalin of the saliva, and is an experiment which any one may try and get an appreciation of the quick action of this body upon the starches. As quick as this action is, the reaction upon starch is never complete in the mouth, and when it passes into the stomach the action of the hydrochloric acid, which it meets with there, destroys the further action of the ptyalin and a final completion of the digestion of the starch is performed by the digestive bodies of the pancreas, especially the amylopsin, after its arrival in the pyloric portion of the intestine. It is said the ptyalin usually acts upon the starch alone, but I think this is not quite true. There is some action upon other ingredients of food as well, but it is so slow in the ordinary chewing of foods as not to be very appreciable and can not be reckoned with as a general action of this digestive body. This is the first act of digestion, which takes place when food is introduced into the mouth, and is practically the only act of digestion which occurs within the mouth itself. The action of ptyalin in the mouth, however, is very much wider than that represented here in the chewing of starchy foods. The starchy foods are pasty and they are certain to stick more or less about the teeth and in the embrasures, and also in the interproximal spaces, if the septal gingivje are a little bit short. After a meal the effect of the ptyalin in dissolving starch will clean up all of these pasty masses and remove them by solution in a very short time. This is another of the very important influences of ptyalin on the health of the membranes of the teeth. If it were not for this reaction of ptyalin, micro- organisms would grow very luxuriantly in these pasty masses and would thus increase the injury to the tissues in all cases of irritation or inflammation. Ptyalin is common to man and to the herbivorous and omnivorous animals, but is generally absent in the carniverous animals. From observations I have made the domestic dog seems to have developed a secretion containing some ptyalin. This perhaps has been developed by its habit of eating cooked starches with which more or less greasy or oily compounds are mixed. This probably does not occur in the wolf, the progenitor 58 SPECIAL DENTAL. PATHOLOGY. of the domestic dog, and does not occur in the cat family, nor indeed in any other animal which is limited to flesh as its diet. Mucus. Mucus is one of the principal colloids of the saliva. It has a close resemblance to albumin and is probably a nucl co-all )um in in its general make-up. It must be understood that mucus appears throughout the body and body juices, and its presence is seen mostly upon what we term the mucous membrane throughout the mouth and the digestive tract, also in other regions, such as the nasal passages, the trachea, the tubes of the lungs, the urinary bladder, and in other cavities of the body. In these various positions, there is much difference in the char- acter of the mucus, depending upon certain elements in its com- bination. We will not go into these questions here, but will discuss only those which are of special interest to the dentist, and avoid all of the chemical questions, further than those included in this statement. Any one who wishes to pursue this subject further will find it fully exemplified in the more com- plete works on physiology. I would refer the student particu- larly to Howell's American Text-Book of Physiology, page 1019. The saliva contains a considerable proportion of mucus. Wlien this is abundant the saliva will be sticky and ropy. This ropiness may in a degree be determined by touching the finger to the saliva and drawing it away, noting how far a thread of it can be drawn. In very ropy saliva we may sometimes draw out this thread to the arm's length. In other saliva again, where the mucus is scant, one can not draw out a thread more than a very few inches. These differences will present the different proportions of mucus in the saliva. The mucus is formed in the salivary glands. Only cells, or groups of cells, in the glands secrete the mucus ; other parts of the glands secrete the watery portion. The mucus is immedi- ately dissolved in the watery secretions from other portions of the same glands and flows through the ducts and is discharged into the mouth in this mixed form. There are other mucous follicles in the mucous membranes of the mouth, in some regions very plentifully distributed, which most of the physiologists whom I have read ignore. These are particularly plentiful in the fauces, and serve especially to lubricate the bolus of food for swallowing. There are also mucous glands scattered through the mucous membrane of the mouth, but these are less plentiful. From these one may see mucus in its pure form, THE SALIVA. 59 unmixed with the saliva. In the mouths of persons who have a considerable amount of mucus in the saliva, these mucous glands of the mouth are unusually active. If one will wash the roof of the mouth with a jet of water from the syringe, then dry it with a napkin, and place the finger in such a position that the tongue can not wipe off and rewet the roof of the mouth, one will note at least a few little globules of mucus appearing. If one of these is touched with the finger, and the finger is then slowly and carefully drawn away, one may be able to pull out a thread of this mucus a considerable distance, possibly as long as the arm will reach. This represents the peculiar characters of the mucus. It is sticky, hangs to everything it touches, and when mixed with the general fluid of the mouth makes that ropiness of which some people complain. The mucus is the substance in the saliva which coats over the teeth, the mucous membrane, and every part of the mouth, and gives the slippery character which we may feel with the fingers during an examination. All of the mucus may be removed in a few moments by jets of water from the syringe, and if the mouth is dried, this slipperyness will have disappeared. This is done more or less every time one drinks water, or more especially by rinsing the mouth thor- oughly with water. The difference in sensation in the mem- branes of the mouth when covered with mucus, and that after the mucus has been washed away, is quite noticeable. The effect of washing the mouth is to remove the mucus. Within a very few minutes the surface of the mouth will be recoated with mucus. The function of mucus is a mechanical one. Many physi- cians speak of this as the only function of the mucus, and usually speak of it only as the lubricant of the bolus of food for swallowing, rendering it slippery for this particular purpose. This is entirely too meager a description of the function of the mucus. The whole of the mucous membrane of the mouth is made slippery by the presence of mucus upon it. The teeth and every part of the mucous membrane and the gingivjB are coated with mucus. In the act of chewing it is intimately mixed with the food and causes the food to slip easily over the surface of the teeth, gingiv.T, and the gums, and prevents most foods from sticking to these parts by its interposition between them and the mucous membrane. In this way it is incorporated into each mouthful of food and facilitates the act of mastication. We could scarcely chew food without it. It causes food, wheni 60 SPECIAL DENTAL PATHOLOGY. crushed by the teeth, to run smoothly through the embrasures to either side of the arch. It also, in the act of chewing, permits the food to be easily thrown back upon the teeth by the muscles of the tongue and of the cheeks. Then by successive closures of the teeth, the food moves back and forth repeatedly in the act of chewing. This is just as important a function of the mucus as is the lubrication of the bolus for the act of swallowing. It is true that this is a mechanical function, but the ordinary amount of mucus found in the normal saliva is entirely sufficient to perform this lubrication efficiently. Some persons, when very much tired out and suffering for the want of water, will remem- ber the difficulty of taking food under such conditions. Lacking this slipperyness caused by the mucus, food becomes unman- ageable in the mouth. AXiBUMIN. Albumin is not usuallj^ reckoned as a normal constituent of the saliva, but it is frequently present. I know of no function that this albumin is destined to perform in the mouth, under normal conditions, and I suppose it is there by accident or some perversion of the secretive processes. In some mouths it is quite abundant and in others it can be detected only by very close chemical scrutiny, the amount is so small. The indications of the presence of albumin in the saliva have never been at all carefully studied, so far as I know. It seems to have been regarded as unimportant by physiologists and pathologists. A certain amount of albumin is found in the urine, and in other secretions as well, including the saliva, and it is regarded as a state in which albumin is being lost from the system through the secretions generally, but through certain secretions more especially. Albumin urea, however, indicates a diseased state of importance and is always looked for very closely by physicians. Salivary corpuscles, so called. A number of those writing of the saliva speak of salivary corpuscles found in it, and there has been some speculation as to what these were and what function they might have. Most of our physiologists speak of them as the remains of leucoytes which have wandered into the saliva and are undergoing disin- tegration. I have searched a considerable number of the more recent, and some of the older, works on physiology, and find no mention in any of them of the existence of globulin in spherical THE SALIVA. 61 form. My search, however, has not been exhaustive, and I may have missed some announcement of that fact. They have not attracted very general attention, however. In the course of my work I happened to run onto these, and by comparison it was easily made out that they were primary spherules of globulin, the same as the spherules that are poured out with the saliva in the formation of salivary calculus, which will be described later. I requested my laboratory assistants to determine the matter of identity or nonidentity by staining methods, in which they found that the two spherules were iden- tical in their reaction with a considerable number of stains ; and as they looked alike and were the same size, they were satisfied that they were actually the same. Therefore, I may state from my own determination made in a similar manner, and from the determinations as repeated by my assistants, that the so-called salivary corpuscle appears to be a spherule of globulin. They are generally round, but not always a perfect sphere. They have no limiting membrane, and the margins are not infre- quently somewhat ragged. They may be seen without staining, and are fairly translucent, the central parts showing dark, while the margins show light. The finding of many of these in the saliva indicates that globulin is being poured into the mouth with the saliva. 62 SPECIAL DENTAL PATHOLOGY. THE INVESTING TISSUES OF THE TEETH — GINGIVAE, PERIDENTAL MEMBRANE, GEMENTUM AND ALVEOLAR PROCESS DISEASES AND TREATMENT IN the consideration of disease beginning at the gingival mar- gin of the peridental membrane the conditions might seem to be very different from those associated with beginnings of dental caries, death of the pulp and alveolar abscess, yet the care of the mouth necessary to the prevention of all of these condi- tions is practically the same. We may find inflammatory conditions in the gingivae of the child, which, while they need attention, may be regarded as somewhat trivial in that they tend to get well with little diffi- culty as a rule. Serious disease of the gingivae does not very often occur in children. During childhood the free gingivae are abundant and cover a considerable portion of the crowns of the teeth. The portion of the tissue in which inflammation begins is usually that which laps upon the crowns of the teeth, rather than the deeper portions lying nearer the gingival line. It is the extension of inflammation, involving the tissues at the gin- gival line that is most dangerous to the future of the teeth. While all of this is true, inflammations of the gingivae of chil- dren should be guarded against as much as possible, and cases occurring should have prompt treatment. Beginning with early adult life the greatest care should be taken as to diseases of the gingivae, for at that time the gingivae have shrunken to their normal length for adult life. Injuries are then apt to become more serious and suppurations are liable to begin at the gingival line, and cut away the tissues, forming pus pockets. After this has occurred and the pockets have made considerable progress, a cure becomes practically impossible. To be effective, whatever is done in the way of prophylaxis INVESTING TISSUES. DISEASES AND TREATMENT. t)3 against this disease must be undertaken before such an occur- rence. This requires of the dentist that he make careful exam- ination of the gingivae of every patient, and if there are inflammations they should have immediate and most painstaking treatment. No matter what may be the cause of such inflamma- tion, it should be searched out to the limit, found and removed. In this way I am persuaded from past experience that the vast majority of these cases can be prevented by removing the dan- ger in its inception. This requires quite as close a watch of patients as that necessary to prevent diseases of the pulp in children. There should be a wide range as to the frequency of the examinations of different patients. Some should be seen regularly every two or three months, others even more frequently, while others present a degree of health of these parts which will permit of the examinations being placed more widely apart. The impression made upon the patient as to the importance of this condition has very great value, and should be carefully made by the dentist, so that the patient will not neglect to con- sult the dentist as often as may be desired for examinations. These little inflammations — and they often are seemingly triv- ial — are usually painless and they may pass on to a sup- purative state, which will do great harm before the patient will realize that anything is wrong. The insidiousness of this class of diseases is such that not many, even dentists, have been regu- larly in the habit of noticing them during the early stages. A little redness here or there seems to be of no consequence, and after a time when the case has gone too far for remedies to be effective, the dentist will find the disease very serious and incor- rectly suppose that it is comparatively recent in its beginning. The matter of the deposits of salivary calculus about the necks of the teeth and impinging upon the free gingivae, is also important. This will cause inflammation of the gingivae and result in shortening and blunting of the margins or crests of the gingivae, and even when they are brought to a healthy con- dition after removal of the calculus, they will not be so good as they were before. The very thin margins, which formerly came up about the teeth, will have become thickened so as to form better lodging places for debris and calculus. Each consider- able deposit that is allowed to harden in such position gives its increment of injury to the tissue, making it worse and worse as to the collection of lodgments. For this reason every patient, in whose mouth a deposit of calculus is discovered, should be 64 SPECIAL DENTAL PATHOLOGY. trained to prevent this and avoid the injury which occurs as a result of occasionally permitting the calculus to become hard. Finally, the whole question of prophylaxis as applied to this condition depends upon the practical care of the dentist, his training in the observation of the inflammations of the gingivas caused by slight deposits, and his influence in bringing his patients to a realization of the danger, as an inducement to them to adopt certain systems of personal care calculated to prevent the occurrence or recurrence of such inflammations. This will be taken up step by step and developed along the lines indicated by modern research. Observation has led me to believe that the injuries caused by such deposits may be prevented in the mouths of practically all persons. Brief Historical Review or the Development of Our Knowl- edge OF THE Diseases of the Investing Tissues. As I look back over the field, the dental profession has never been disposed to give the diseases of the gingivae and peridental membrane accurate and careful study as to patho- logical conditions. For what seems to me to have been a long time after I began practice, no attention was, witliin my knowl- edge, given to these conditions, except to remove calculus when patients appeared with incrustations upon their teeth. Names applied to diseases of the investing tissues. The group of diseases of the investing tissues of the teeth have, without differentiation, had more names than any other group of pathological conditions occurring in the mouth, and new names are being continuously introduced. The earliest writers were content with the terms spongy gums, inflamed gums, loosening of the teeth, or others of similar import. Generally, the entire subject was disposed of in a single paragraph, or at most in a page or two. In the sixties and early part of the seventies. Dr. J. M. Riggs, of Hartford, Connecticut, brought this subject promi- nently to the notice of the profession by clinics which he made before dental societies, rather than by writing. For a time Dr. Riggs' methods had quite a following, and the condition came to be called Riggs' Disease. This term is still seen occa- sionally in the literature. The term Pyorrhea Alveolaris was proposed by Dr. F. H. Rehwinkel, of Chillicothe, Ohio, in a paper before the American Dental Association at its meeting in Chicago in 1877. It may be said that this name lias become the most popular term for INVESTING TISSUES. DISEASES AND TREATMENT. 65 the group of diseases of the tissues investing the teeth. The term pyorrhea alveolaris means the running of pus from the alveoli. It covers too much and does not properly describe the disease to which it is applied. I do not intend to use this term in this writing. This is not from any captious objection to it on my part, but because I wish to describe the several diseases under different names to distinguish them and make each as clear as possible. This I could not do under the single term pyorrhea alveolaris. In studies of the cast of mind of people, dentists as well as others, it will be observed that in order for a particular thing to be understood as a separate and distinct entity, it must have a distinct name, and this is as true of disease as it is of anything else. In 1882, in a paper* before the Illinois State Dental Society, I proposed the term Phagendenic Pericementitis to apply to that form of disease in which pockets were formed alongside the roots of the teeth. This term goes no farther than to locate and describe the destructive character of the inflammation of the peridental membrane, a fact well known. This term phagedenic was formerly much used in describing certain ulcers which refused to heal and tended to the progressive destruction of the soft tissues. It means to devour or destroy by eating away. The term Chronic Suppurative Pericementitis, which means the same and is more readily understood, will be used in this book. In the paper referred to above, I proposed the terms Calcic Gingivitis and Calcic Pericementitis, as describing the form of disease caused by accumulations of salivary calculus upon the teeth. I believed the conditions presented well worthy of this distinction. Similar terms will be used in this book as a part of a simple classification of the several types of inflammation which will be described. The term Alveolitis was, I believe, first used by Dr. Adolph Witzel, of Germany. It is being used by a number of American writers and is frequently seen in the literature. If this term, by its original definitions, had been made to apply to the soft tis- sues within the alveoli of the teeth — the peridental membrane — it would not have been far from correct. But it seems to have been proposed and defined with the idea that the principal seat of the disease is in the margins of the alveolar processes. This is, to my mind, an incorrect statement of the conditions. * Phagedena Pericementi. Proceedings Illinois State Dental Society, 1882, p. 93, 66 SPECIAL DENTAL PATHOLOGY. as the alveolar process is the last of the investing tissues to become involved. Dento- Alveolar Pyorrliea and Interstitial Gin- givitis are occasionally seen in the literature, as are other terms referring to diseases of the peridental membrane, which have their beginning at the gingival margins. Dr. Riggs' TREATMENT. One of the oldest discussions of Dr. Riggs' treatment occurs following a paper on Salivary Cal- culus read by Dr. Thos. B. Hitchcock before the Connecticut Valley Dental Society in 1869, and reported in the Dental Cos- mos, Vol. XI, 1869, p. 412. At this time Dr. Riggs brought before this society a patient, Dr. Goodrich, for whom he had operated before this same society two years earlier. Dr. Riggs stated that he had been operating in the same way for twenty- five years, and the majority of his cases were successful. In those days the essays and discussions of the Dental Societies were not reported so fully as in more recent times, and it is very difficult to trace the date of origin of important discoveries or events which occasionally become of special inter- est. Dr. Riggs made some important statements regarding his treatments, which were published in the Dental Cosmos in 1882, p. 524. This was five years after the paper by Dr. Rehwinkel, and when the treatment was rapidly slipping away from the plans adopted by Dr. Riggs. His operation for the cure of these conditions was very simple, and without differentiation between the inflammations caused by deposits of salivary cal- culus and those in which pus pockets were formed. In prac- tically all cases the operation was the same, except as to the extent of cutting required. The gingivae and gum tissue were cut away sufficiently to remove all diseased tissue to the line of attachment of the peridental meml)rane. It was usually neces- sary to cut away more or less of the uuinflamed gingivjp of neighboring teeth in order to have a reasonably even line of attachment aftei*ward. This operation will often leave con- siderable of the cementum exposed when cases have healed. It seems that many of Dr. Riggs' cases did well. In my own use of this plan in some very bad cases caused by deposits of salivary calculus, in which there was a great thickening of the gum tissue, I have been surprised at the rapidity of recoveiy and the readiness with which the soft tissues accepted the new line of attachment. The treatment was })loody, often extremely so, but the hemorrhage ceased promptly and was of no conse- INVESTING TISSUES. DISEASES AND TREATMENT. 67 quence. Generally no medication was used, ^^^atever else Dr. Riggs may have accomplished, he certainly succeeded in calling the attention of the profession to the treatment of dis- eased gingivae as had been done by no one else. De. Rehwinkel's paper. Dr. Rehwinkel's paper in 1877 was by far the best writing upon this subject up to that time. It abounds in inquiry rather than in the discovery or announcement of principles of pathology. It is rich in references, and espe- cially in quotations from both American and European authors. Taken altogether, it gives a good view of the opinions of men regarding the diseases of the gingiviP at and before the time at which it was written. Although it set a landmark in the name to which it gave origin, it did little to advance our knowl- edge of these diseases. A feature of the paper that seems curi- ous to one reading it now is the fact that no hint is given of the pus pocket as such, or as a distinct entity in the patholog^^ of the peridental membrane. The nearest approach to this idea is the mention of the peculiar form of calculus which occurs on the sides of roots when the membranes have been destroyed. He states that this calculus is something different from salivary calculus. In his quotations there are many suppositions regard- ing systemic conditions as causative factors in inducing disease of this tissue. Gouty diathesis as a theory. These events occurred at a time when there was the wildest use of antiseptics in the treat- ment of suppurative conditions wherever found, and often with- out much regard to other conditions. This may have caused the neglect of the study of the pathology which is so general in the writings on the su])ject. It is true that from time to time suggestions as to the pathology have been advanced. Many of these have been based upon suppositions regarding systemic causative influences, as a connection between the gouty diathesis or uric acid dyscrasia and pus pockets on the roots of the teeth. Perhaps an article* by Dr. Edwin T. Darby, of Philadelphia, in 1892, gives the best expression of this thought, which had a wide influence for a considerable time. The treatment for the uric acid dyscrasia seems to have been tried out very thoroughly by a number of practitioners. However, we may judge that such treatment has not been sufficiently successful to justify its con- tinuance. Gout and rheumatism are eminently nonsupi)urativo diseases, while diseases of the peridental iii('inl)raiie are as * Dental Erosion and the Gouty Diathesis. Dental CosTnos, Vol. .'Hi, 1892, p. (5129. 68 SPECIAL DENTAL PATHOLOGY. remarkable for their suppurative features. They stand wide apart. In the course of the discussions referred to it was announced by Dr. C. N. Pierce* that he had found calculus on the sides of the roots of teeth not before diseased, about which abscesses occurred, and that these calculi showed uric acid by the murexid test. Very soon there were other cases reported. It then looked as if we should have to use this test upon any calculus found in the mouth as a diagnostic feature. Under these conditions I undertook a bit of work in this line. I was skeptical regarding the finding of calculi on the sides of the roots of teeth as the initial step in the formation of pus pockets. The conditions causing lateral abscesses had been so persistently overlooked by others that I felt free to question this statement. The peridental membranes are often deeply diseased with but little showing superficially. One who is not habitually examining the subgingival spaces may readily overlook the existence of pus pockets until he is surprised by a lateral abscess. I was at the time seeing many patients in various condi- tions of physical health; good, medium and bad. Some had diseased gingivae, some had not. Some had rheumatic or gouty tendencies, some had not. From these I gathered calculus with written records, made the tests, and made a reportf in 1894 as a reply to the findings of Dr. Pierce and others. I found the test entirely unreliable as showing a uric acid dyscrasia. It was occasionally absent when it should have been present, and was often present when it should have been absent. The fact seemed to be that the small amount of uric acid present in the blood in normal conditions might give color in salivary calculus by this test. It was therefore useless as a diagnostic feature. Special infection theory. There has been for many years an almost incessant search for some special infecting agent which serves as an initial cause of the foiTnation of pus pockets, and the gradual spreading of these through the mouth. This search, in which I myself was active for a long time, has not, up to the present time, brought definite results. No complete studies of the micro-organisms normal to the human mouth have yet been well presented in any book or writing. Dr. • Etiology of Pyorrhea Alveolaria. International Dental Journal, Vol. 15, 1894, p. 1. f " Diseases of the Peridental Membranes and the Uric Acid Diathesis." Dental Review, Vol. 8, 1894, p. 449. INVESTING TISSUES. DISEASES AND TREATMENT. 69 Miller and others have isolated many species of organisms from the saliva, but we should know accurately what micro- organisms are normal to the human saliva, or may always be found there. All others found there will be in the saliva by accident, i. e., accidentals. These may or may not be pathogenic varieties. Some years ago I took up the subject in this way. A certain number of plants were made from each mouth and plated out. Pure cultures of each organism, which would grow and form colonies on semisolid media, were obtained and their pathogenic properties tested by inoculation of animals. The distinct forms were listed, and divided into two groups; those which were normal or constant in the saliva and those which were acci- dentals. In this way I studied many mouths, trying to find the organisms normal to the saliva, or those present in every mouth which was well kept, and the additional organisms found in a series of mouths not well kept. These investigations showed certain organisms constantly present in the mouths of careless persons which could not be found in the mouths of persons who were careful as to cleanliness. Many other facts will appear in such a course of study which will surprise most bacteriologists, even those who believe themselves well acquainted with the flora of the human saliva. About fifteen varieties will probably cover the organisms that are constant, only about half of which can be cultivated upon the ordinary media, semisolid or fluid. All of the others are accidentals. In one locality some of the accidentals may persist for one or two years, and then disappear. I found one organism constant in Chicago among both students and infir- mary patients, for two years — 1892 and 1893. I had never seen it before. The third year it had disappeared completely. It did not occur in my cultures in Jacksonville, 111., two hundred and forty miles away. Taking just this small line of facts, one will see that it is not safe to rush into print on such a proposi- tion. To try out these organisms on animals as to possible pathogenic qualities, is in itself a large undertaking. I found that, with my practice, I could not have the time to make this line of work complete. It is expensive and exacting as to both space and care to keep the necessary animals for pathological tests in such a way that they will not contaminate each other. We need young men with sufficient financial support to enable them to do this work. It is only by such work that we will ever obtain that ])road view of this subject which is so 70 SPECIAL DENTAL PATHOLOGY. desirable. At present we are unable to definitely place any organism, except the one constant in the saliva, the staphylo- coccus albus, in a causative relation to the suppurative features of diseases of the gingivir. When the inflammations are begun by traumatisms of any kind, this organism will keep up pus formation as long as there is a pocket in which it can remain enclosed. It is not a virulently pathogenic organism. It is common to the skin and is the organism generally found in boils. Without some break that gives it an advantage, it will not ini- tiate a condition of disease in the mouth or in the skin. Serum treatment. Serum for the control of suppura- tions is being sought for by many bacteriologists and other researchers. As a general principle it would seem that any infection which is self-limiting should be controllable by an immunizing serum. This is in accord with the theory that the poison eliminated by the causative organism arouses the forma- tion of an antibody by the tissues themselves, which destroys the effect of the micro-organism. Such a serum may be employed to estalilish immunity, or it may be administered soon after exposure or at tlie beginning of an attack, and either pre- vent the attack entirely or materially moderate it. In this group of diseases a more or less permanent immunity is estab- lished by the use of serum. In the use of serums to control suppurations, it is not expected that immunity will be established. The patient may be cured of the particular attack, but there will be no lasting effect against another similar attack. Many cases of peridental disease have been reported as much improved by the use of serums, the same as pyogenic infections in other parts have been benefited. There has, however, been no cure of the pus pocket by such treatment, even though the discharge of pus might have been temporarily stopped. The denuded cementum has remained as a continuously acting irritant, and as soon as the effect of the serum has passed, conditions are favorable for the re-establish- ment of the infection and pus formation. Regardless of the success of this and other methods of treating suppurative infections up to the present time, or of the further progress of this, work in the future, it does not appear to-day as though we can hope for relief in the applica- tion of these methods to the pus pocket alongside of a root, for the reason mentioned above, that we are unable to remove the continuous irritant. INVESTING TISSUES. DISEASES AND TREATMENT. 71 The TREATMENT IN VOGUE. All of this lias had but little influence in shaping the general treatment now in use for chronic suppurating pockets. The treatment generally in vogue has con- sisted of the removal of deposits of serumal calculus which were found adhering to the cementum where the soft tissues had been parted from it, and the use of antiseptics in an effort to control the discharge of pus. The supposition was that the soft tissues would become reattached to the cementum if they had a favor- able opportunity. This, it was thought, would bring about a cure of the condition. This is a succinct statement of the prac- tice now most generally employed in pus-pocket conditions. Has this treatment proved satisfactory? Have cases pre- senting deep pus pockets on the sides of the roots of teeth healed and remained well afterward under reasonable care by the patient? In this, it is not a question whether cases come to look better and to show less flow of pus under this treatment, but do they really get well with a reasonably good reattachment of the soft tissues to the cementum ? I have had a long and very careful observation of this treat- ment, both in my own practice and in the examination of patients who have been under treatment by others. I have found much improvement in general conditions of the gingivae as examined by the eye. I have seen cases which had been bad, with much pus issuing, improve so that no pus was apparent. Such have been common in my own practice, and I am sure this is true in the practice of others also. However, a careful examination with the subgingival explorer showed that the pockets had not closed, and subsequent observation revealed the fact that the tissues of the gingivae had not maintained a healthful tone. I have myself kept patients on and on in this condition, all of the time having them make frequent visits for inspection and direction as to cleaning, all of the time making frequent use of antiseptics. These cases have apparently done fairly well in the main, but have never really gotten well by reattachment of the tissues to the cementum. Some of them would show only occasionally an acute inflanmiation ahout some particular tooth, or teeth, which passed away, leaving the pocket deeper than before. In this slow way the cases became worse. In some of the cases I placed the loose teeth in bands con- nected with other teeth to hold the looser ones steady. As the roots became more and more difficult to keep clean, on account of the broadening of the already wide pockets, I cut off and 72 SPECIAL DENTAL PATHOLOGY. removed the roots, leaving the crowns in the gold bands to serve the purpose of mastication. This was certainly pushing the preservation of the natural teeth to the limit, and I came to so regard it. I have since had reason to believe that I went much too far in my effort to cure. Much too large a percentage of those people are dead. As it was with my patients, I believe it has been with patients of others. After the use of the forceps I have seen many of these sallow, not much sick but complaining persons, brighten up and again enjoy life. STUDIES OF SALIVARY CALCULUS, 73 STUDIES OF SALIVARY CALCULUS ILLUSTRATIONS: FIGURES 122-143. Salivary calculus is the term applied to the calculus which enters the mouth with the saliva, and becomes deposited upon the teeth, plates, or other hard substances within the mouth. The word salivary is used to distinguish this deposit from the calculus which may be deposited in the gall bladder, urinary bladder and elsewhere. Since other calculi found in the body are very closely related, the gall bladder calculi being formed of cholestrimi instead of calcium salts, and since the underlying causes of all are probably similar, the investigations here pre- sented apply in large measure to all of the various forms of calculi. In fact, it will be shown that there is little question to doubt but that the elements necessary to the formation of the deposit in all the various places in which it may occur are pres- ent in all simultaneously and lack only the local nidus which is necessary to a beginning accumulation. Composition. Salivary calculus is composed of calcium phosphate, with the addition of smaller amounts of calcium carbonate, held together in mass by an organic compound which, according to general opinion, is formed after the material has been deposited upon the teeth, natural or artificial. The fresh deposit is very soft and greasy to the feel of the fingers, insoluble in water, in alcohol and most fluids that one would be likely to tiy. This mass I have called agglutinin, or agglutinin of calculus. When it is deposited upon a plate, or upon the teeth, it may readily be washed away and the plate or the teeth perfectly cleaned with an ordinary brush and water. This, however, must be done within five to twelve hours after the material has been deposited, if it is to be removed easily. If one waits twenty-four hours it has begun to harden and it is difficult to remove with the brush. If one waits for several days or a week, it can not be brushed away. It continues to increase in hardness for one or two months, and at the end of this time is fully hard. When it has become hard, instruments are required to break or to scrape it awav. 74 SPECIAL DENTAL PATHOLOGY. The deposit does not occur in every month. In some mouths, there will be an occasional deposit, with long periods during which there is none. In others the deposit seems to be occurring all the time. Generally children and young people are freer from deposits of calculus than adults. Quite a number of cases occur in which persons have no deposits until they are forty, fifty or even sixty years old, and afterward are much troubled with it. These may be said to be general conditions noted by every dentist who is a good observer and has had many years of practice. It gives the idea that there is a systemic dyscrasia which is responsible for these deposits. Analysis. In the text-books, a number of analyses of sali- vary calculus have been published. These differ considerably. A part of these differences are due to variations in the amount of water and mucus, and the fact that a number of them combine water and organic substances in their report. One may analyze calculus fresh from the mouth, only drying it upon blotting paper. Another may have analyzed calculus that was old and thoroughly dry. Unless these conditions are stated, the amount of water will vitiate the figures of the whole analysis. I give here an analysis by Scliehevetskey* which gives as good an idea of its composition as can be obtained from these analyses. Such reports would naturally vary, for I do not suppose calculus is a strict chemical compound of invariable composition. Water and organic matter 22.07 Magnesium Phosphate 1 . 07 Calcium Phosphate 67 . 18 Calcium Carbonate 8.13 Calcium Fluoride 1 . 55 100.00 In a number of the analyses no magnesium phosphate is reported ; in some a little calcium fluoride is reported. STUDIES OF DEPOSIT OF SALIVARY CALCULUS. Considering the length of time in which the deposit of salivary calculus and the great injury it has done to mankind have been observed, the history of the study of it in the literature * Burchard on "The Orifjin of Salivary Calculus," Dental Cosmos, 1895, p. 821. Also see Burchard's Dental Pathology, edition of 1898. A considerable number of these analyses are very old, and may be traced from book to book from away bat-k to the first half of the last century, or even earlier. I have noted in a few of thorn that errors in transcribing have occurred, and have been carried on from one bonk to another. STUDIES OF SALIVARY CALCULUS. 75 is very disappointing. Until quite recently it would seem that no successful effort has been made to penetrate this mystery. All, or nearly all, have agreed upon certain points and there the subject has been dropped. The essential facts in the writ- ings of many men may be covered in a few sentences. The points on which most men have agreed have been these : Calculus is composed mostly of calcium salts which are pre- cipitated from the saliva. These salts find lodgment and settle in out-of-the-way places about the teeth, and become aggregated by entanglement in partly inspissated mucus or other colloids from the saliva. In these positions the material settles into more compact form, as the colloid material is slowly decom- posed, and hardens into stone-like masses. These masses grow by more or less constant additions upon the hardened or harden- ing material, until, sometimes, quite large and thick masses of it are fonned. These masses are in part in contact with the soft tissue investments of the teeth, and cause them to become inflamed and to be destroyed partly by absorption and partly by suppuration, resulting in the loosening and final loss of the teeth. Among the writers much difference of phraseology may be observed, but the whole subject is practically included in the above statement. The late Dr. A. W. Harlan was to prepare a paper on salivar^^ calculus for the American System of Den- tistry which was published in 1886. In a conversation regard- ing this paper he stated that there was little to write, as the subject really had no literature, and nothing was positively known about it. He finally offered an article which is printed in the second volume, page 273 of that work, consisting of nine- teen pages. Four of these are taken up in quotations from thirteen different authors, two to a discussion of green stains on teeth and the remaining pages to the removal of calculus from the teeth. This statement strikes me as the most graphic representation of the little that iras known of the subject up to that time, that I could now write. Dr. Burchard's studies. Since the publication of the Amer- ican System of Dentistry, further efforts have been made to advance our knowledge of this sul)ject. The most notable of these will be found in Dr. Henry H. Burchard's article* on "Tlie Origin of Salivary Calculus" in 1805, and in his bookf published in 1898. In a second edition of the book, since Dr. Burcliard's * Dental Cosmos, Vol. 37, 1895, p. 821. t Dental Pathology and Therapeutics, 1898, p. 447. 76 SPECIAL DENTAL PATHOLOGY. death, his ideas have not been veiy closely followed. From the frequent references to assistance and support by Dr. E. C. Kirk, of Philadelphia, it would seem that he had Dr. Kirk's assistance in the development of his subject, especially in the preparation for, and the carrjang forward of, the experimental work, the results of which form the basis of the presentation in both the journal article and in the book. In order to fully comprehend a short resume of this work and its conclusions, one should have in mind the following well- known facts: Carbon dioxid dissolves in water or fluids con- taining water. When a fluid contains this gas in solution, its power of dissolving certain salts is markedly increased. The excess of salts thus dissolved above saturation without the car- bon dioxid, will be precipitated if the carbon dioxid is removed. If the pressure of the atmosphere is increased — as by pumping carbon dioxid into a closed space with an air pump — the amount of carbon dioxid dissolved in the liquid is increased and its power of holding salts in solution is increased in a similar pro- portion. If now the pressure which holds the carbon dioxid in solution is relieved and the extra portion of carbon dioxid allowed to escape, the extra proportion of a salt dissolved under pressure will be precipitated. In the animal body carbon dioxid is continually being formed by tissue metabolism and eliminated, mostly by the lungs, but always leaving a residue in the tissues and body juices. There- fore, all of the fluids of the body are, in a degree, charged with carbon dioxid, and its power of holding salts in solution is influ- enced to some extent by the blood pressure. Therefore, these fluids, as well as the secretions and excretions derived from them, may have a little more carbon dioxid and a little more calcium salts in solution than they will retain after removal of this blood pressure, which they lose when secretions which contain them are exposed to the air. In such a case the extra amount of calcium salts in solution, if there be any in excess of ordinary saturation, will be precipitated. It is only by experimental results that we can know whether such an excess exists in any particular secretion. The propositions made by Dr. Burchard are reducible to two, around which the whole experimentation and argument hinges. These are: 1. Saliva contains calcium ])hosphate and other salts in solution, held ]»y dissolved carbon dioxid. When delivered into STUDIES OF SALIVAEY CALCULUS. 77 the mouth, the normal pressure on the body juices is relieved, the carbon dioxid escapes and a portion of the calcium phosphate and the other salts is precipitated. 2. Mucus is a normal constituent of saliva. Lactic acid is being continuously formed in the mouth by certain micro- organisms. Lactic acid converts mucus into a curd in which the precipitate of calcium and other salts becomes entangled, and this hardens in the form of salivary calculus. These statements agree with the views generally held as to the nature of these deposits. In the experimental work reported, it was found that freshly collected saliva cleared by filtering,* or otherwise, and placed in an open test-tube, will have become cloudy the next day. The interpretation was that the saliva, known to contain calcium salts in solution, slowly lost its carbon dioxid and the excess of calcium salts was precipitated and formed the cloud. Another strong feature of Dr. Burchard's experimentation I may fairly express in this way. The mixed saliva contains a considerable proportion of mucus as a normal constituent. Tliis mucus is precipitated by lactic acid in the form of a curd, which rises to the surface, the amount and strength of which will be in close relation to the strength of lactic acid used. This curd may be seen when a few drops of one per cent lactic acid are dropped into a test-tube of freshly drawn and cleared saliva. A much stronger curd is formed by a few drops of ten per cent lactic acid. The saliva of different persons and of the same person at different times contains a variable amount of mucus, and the amount of this curd will also depend upon the amount of mucus in a particular specimen of saliva, as well as the percentage of lactic acid added. The supposition expressed is, that the pre- cipitate of calcium salts, falling out of solution, becomes entangled in the slight curds of mucus fonning in undisturbed places about the mouth. These become harder and stronger, forming salivary calculus, which grows very slowly ])ut in time foraas solid, stone-like masses. These are in positions in wliich they can slowly settle without too much disturbance from the movements of the tongue and the buccal and labial mucous mem- branes, as along the crests of the free gingiva?, especially in places where there is a slight thickening of the crest, which will afford a little protection against the rubbing of tlie tissues and * In the filtering of saliva much of the colloids remain on the filter, changing the composition in that degree. This is avoided by clearing veitli the centrifuge, or by allowing the saliva to stnnd until it settles. 78 SPECIAL DENTAL PATHOLOGY. of the food which is eaten. This idea is in some difficult^^ to account for the almost universal observation that the first and greatest deposit of calculus occurs on the teeth nearest to the ducts of tlie salivary glands. The papers mentioned are well written and their appear- ance marked a new era in the study of this subject. Since their publication they seem to have served as the basis of thought for other writers. I will show in the next few pages, however, that the cloud formed in the test-tube, supposedly calcium salts precipitated with the release of carbon dioxid, was not calcium salts but a growth of micro-organisms, and that salivary calculus is deposited in a substratum of globulin and not in a coagulated mucus ; that a very considerable deposit may occur near the salivarj^ ducts within a few hours instead of this slow settling- down in the out-of-the-way places, etc. Again, lactic acid, which is added to saliva in a ten per cent solution in order to form a strong curd — as expressed in Dr. Burchard's account of his experimentation — would convert a precipitate of calcium phos- phate into a highly soluble lactate, which would be carried away in the oral fluids instead of forming a hard concretion. Again, the formation of what I originally called the gela- tinuous plaque, gelatinoid plaque, etc. (always avoiding a strictly chemical term, of which I was uncertain), has appar- ently been found to be by the coagulation of mucin into a film or mass by lactic acid.* This is developed by the growth of a colony of micro-organisms occupying a sheltered position, and which is more perfectly covered in by this film. This condition prevents the acid formed by the organisms from being dissi- pated in the general saliva. The result is a solution of the cal- cium salts of the enamel, forming caries of the enamel. Hence, we see that the scene of the coagulation of mucin by lactic acid, is that of a solution and conversion of the less soluble phos- phates into the more soluble lactates. This was well shown by Dr. W. D. Miller in his original experiments, by which he deter- mined the phenomena of caries of dentin (Ajnerican System of Dentistry, Vol. 1, p. 791). This again shows definitely that a coagulum of mucin by lactic acid would not become the scene of the entanglement of precipitated particles of calcium salts for the formation of the hard concretions, such as salivary calculus. * " Some Conclusions Growing Out of a Study of the Cause of Dental Caries," by Charles E. Jones, Dental Review, 1911, p. 1167. STUDIES OF SALIVARY CALCULUS. 79 Therefore, it seemed necessary that we find some other explana- tion of the formation of salivary calculus. Personal Investigations of the Deposit of Salivary Calculus. The following report of my investigations of the deposit of salivary calculus is written after about five years of experi- mental work. Naturally many experiments were pursued with results which were of little or no value, others failed from one cause or another. For this writing I have selected and reported only those which have added something to our knowledge of the subject. These are presented in what seems now to be the most logical order, without regard for the order in which they were actually made. During these investigations I have written two articles in which the knowledge of this subject developed at the time of writing was presented. The first of these, entitled ** Beginnings of Pyorrhea Alveolaris — Treatment for Prevention, etc., ' ' was published in the Items of Interest, Vol. 33, 1911, p. 420. The second, entitled ''Deposit of Salivary Calculus," was published in the Dental Review, Vol. 26, 1912, p. 337. A special machine was designed and built for the purpose of grinding microscopic specimens of hard substances, such as deposits of calculus, teeth, etc. This machine is described at the end of the book, and is illustrated in Figures 508 to 518. As a basis for my experimental work, I duplicated the work reported by Dr. Burchard. I made the same experiments in filtering freshly collected saliva and observed the cloud which was present in the test-tube the next day — the cloud which had been interpreted to be composed of calcium salts precipitated by the gradual loss of carbon dioxid from the solution. It occurred to me that this experiment was unfinished; it had not been proven that the precipitate was calcium salts. Test of saliva for precipitate of calcium salts. I devised an instrument by bending a small wire in a loop and then twisting one of the ends around the other for a suffi- cient length to reach nearly to the bottom of the test-tube. '^Flie ends of the wire near the bottom of the tube were converted into a spring clutch, into which I placed a cover-glass which would nearly fill the inner circumference of the tube, in a horizontal position. This was let down through the clouded portion to within a half-inch of the sedimont wliich had collected in clearing the saliva, without disturbing it. I tlicii phiccd this test-tube in 80 SPECIAL DENTAL, PATHOLOGY. the electric centrifuge, and allowed the machine to run fifteen minutes. On examination through the test-tube I found the liquid above the cover-glass clear and a film on the cover-glass. The fluid was now drawn away as far as the cover-glass with a pipette, so cautiously as not to disturb the film. Then the cover- glass was lifted out. When this was brought under the lens of the microscope, it did not show a precipitate of calcium salts. The cover-glass had on it a film of micro-organisms. This result occurred in every effort to prove the findings related. I have not yet been able to find the least trace of precipitated calcium salts, though I have made many efforts. I had previously fully believed that such a precipitate did occur and the results obtained were disappointing. Examination or deposits on artificial denture. My recent studies of the deposit of salivary calculus were undertaken soon after I began wearing a full upper plate, a little more than five years ago. My first plate presented the opportunity to observe the deposit of salivary calculus which I occasionally found upon it. After a time, I found some features which had never before been presented. I then began a sys- tematized study of the conditions under which deposits occurred. At first this consisted of a record of the appearance of calculus in soft form upon the plate. In pursuing this, I soon discovered that the mucous coating which covered the plate and made it slippery to the fingers, could be washed away by placing the plate in still water for a time, or in running water, as a jet from the ordinary hydrant, without disturbing the freshest and soft- est deposit of calculus. The following then became the mode of examination: After each meal the plate was laid under the hydrant and the water turned on it for a few minutes, removing the mucus. It was then examined for deposits of calculus. These were found only occasionally. Sometimes two to four weeks, or a longer time, would pass without any deposit what- ever. Then suddenly a heavy deposit occurred. After the wash- ing with running water, and the examination, the plate was always made clean in every part. The deposit seemed absolutely insoluble in running water, hot or cold, yet it was so soft that it was readily cleaned away with a brush and water. Nothing more was needed. Generally the deposit was divisible into three zones : a cen- tral greyish-white zone, an intermediate semitransparent zone and an outer transparent zone. The whole deposit felt greasy Fig. 122. Fm. 12:5 Fig. 122. A device attached to a plate for artificial teeth, used for the collection of specimens deposited directly on a piece of the usual cover-glass for microscopic objects. It consists of a frame of No. 20 gold plate fastened to tlie plate with a gold screw at each end. All of the central part is cut away, as shown. The vulcanite has been cut Hat over the area covered by the frame, and above and below ledges are left which will prevent, a glass cut to fit the space slipping out in those directions. The screws keep it from slipping out endwise. The cover-glass is laid in the space, the frame is laid upon it, and screwed do\vn. This exposes all of the central i)art of the cover-glass for the collection of films. When a film has been dei)osit('d on the glass while being worn in the mouth, the screws are removed, the franu' lifted oil', and the cover-glass, with the film undisturbed, is removed and transferred tu the li(|uids ])repar{!d for the staining process. A similar device may lie attached to tin- natural teeth in such a way as to be removable. Fig. 12.3. Photomicrograph of agglutinin of salivary calculus moderately well filled with calcium salts, but very soft. Jt was jiressed down iimler a cover-glass in a thick solution of sludlac in alcohol, after thirty minutes in alcohol to icinove water. The general appearance of spherides is fairly well sec^n. Figures 122 to 134 and Figures 138 and 139 were originally publislied in the Items of Interest, illustrating a pajier entitled: " Beginnings of rvorrlie;i Alveolaris, Treatment for Prevention, elc," Vol. 'M, I!M1, p. -120. *» Fig. 126. Figs. 124, 12.'5, 126. Agglutinin of salivary calculus showing irregular spherules laid flown on cover-glasses worn in the mouth. Eosin stain with formalin as a mor- dant. The stain is diffuse. In this deposit the thickest spherules show darkest. The finer spherules, of which these are made up, arc not distinguishable in the pictures. The tendency to form larger spherules by the combination of smaller ones is apparent, but presents the utmost irregularity in the different specimens. Note. — The beginning of the deposit always occurs in the little angle formed by the frame and the cover-glass (see Figure 122), and grows out upon the glass from that beginning. The cover glass has generally been removed before being completely covered, in order to have thin margins. All the specimens are so placed that that portion next to the frame is down in the illustration. Fig. 127. Fig. 128 Fig. 127. Ground section of hard salivary calculus i/^ of Viooo '"^'* thick, show- in{T sphcmlos in thn upper part of the field. While these spherule forma arc hard ciilenhiH, that portion has not received as niucii calcium salts as it would have con- tained later. The splierules finally become almost completely obscuretl, as seen in the lower portion of the illustration. Fig. 128. Photomicroffraph from a section of a crumb of very black scrumal calculus. (Sec descriiition of this process of jjrindiny in the Appendix.) The outer surface is the lower border of tiie picture, upon which accretion was in progress. It gives a slight showing of spherules. The irrf«,'uhir veining siiows lines of accretion. Fig. 129. Fig. 13U. Fig. 129. A stain by nigrosiii following pliciiol. Certain of the spherules do not stain at all; otherwise the stain is diflfiisive. A number of light-colored circles will be seen in the upper part of the field, which are unstained spherule.s, with a collection of fine granules about them that take the stain poorly. Many of these white spherules ajipear in the tiiicker portions partially covered with spherules that stain. Therefore their outlines aj)pear irregular. Many of these peep through the thicker portions as white points. Fig. 130. Appearance of a rapid deposit (about four hours), stained by nigrosin after treatment by formalin as a mordant. So far as the stain goes it is diffusive, but many of the primar}-^ spherules refuse the stain, which gives a lobulated appearance. STUDIES OF SALIVARY CALCULUS. 81 and sticky to the fingers. It was coagulated and whitened by boiling water in a similar way as is white of an egg — egg albu- men. Phenol or alcohol produced a similar effect. Therefore, if this material is not albumen, it is something closely approach- ing it in chemical composition and reaction to coagulating agents. It seems clear that it is not coagulated mucin, or the settling of a precipitate from the saliva, like that in the teakettle in which hard water is boiled, as taught by Burchard. Collection of deposit on cover-glass. While my series of observations on conditions of deposit were continued, I made every effort to find means of displaying the stinicture to better advantage. Finally the idea that I might construct a trap by which I could catch the mass on a cover- glass, suggested itself, and was quickly carried out. This trap consists of a little frame of gold plate fastened at either end with a screw, under which a cover-glass may be laid. (See Figure 122.) A space for it on the plate is cut flat, leaving square shoulders at either side to prevent the cover-glass from slipping out. The trap is depressed a little below the general level of the surface of the plate, in order that deposits on the glass will be less likely to be disturbed. The traps which I have used take in a cover-glass five-eighths by five-sixteenths of an inch. They may, however, be made of any size or form. At first cover-glasses were altered by grinding them on the emery-stone to fit the space, but later a dealer cut the special form for me. A trap may be securely attached to one or two natural teeth in easily removable form. It has one advantage over the trap attached to a plate, in that it may be removed and dropped into water while eating, avoiding all danger of disturbing the form of a deposit in chewing food. One who wears a plate may have one plate to wear at meal-time and another carrying the trap to wear at other times. In this way the danger of dis- turbing the deposit in chewing food will be obviated. On these cover-glasses I caught the fresh deposits in the foiTQ in which they were laid down, and soon learned to avoid those which were too thick for microscopic study. The deposit would invariably begin in the little angle formed by the meeting of the gold plate and the cover-glass, and spread from that out over the cover-glass. It was desirable to remove the cover-glass before it was completely covered with deposit, in order that a thin margin would be presented for study. Tlie screws were removed, the frame lifted, and the cover-glass with the deposit 82 SPECIAL DENTAL PATHOLOGY. transferred to the fluids for washing, staining and otherwise preparing for mounting. When the material was mounted in balsam, without other preparation than the removal of water with alcohol, it became so transparent that nothing could be seen, except where it was thickly filled with calcium salts, and even there no form elements could be discovered. Therefore, some kind of stain became necessary. Staining. I found that this material could not be stained by the ordinary processes for staining tissues or micro-organ- isms, for the reason that all of the stain would wash out. By using stains soluble in absolute alcohol, increasing the strength of the solutions, and leaving the specimens in them from twelve to twenty-four hours, then giving an hour or two in absolute alcohol for removal of excess of stain, fairly good selective and diffusive stains have been produced. A ten per cent solution of gentian violet in absolute alcohol, and a saturated solution of eosin in absolute alcohol, gave very satisfactory results. Gen- tian violet is a selective stain. Eosin is a diffusive stain. Nigro- sin answers certain purposes very well, since it shows selections which other stains do not. Many other stains have been tried but have not given better results. By using formalin, four per cent solution first, as a mordant, the time required for staining is much reduced. Phenol, twenty per cent, produces a similar result. As to the use of the stains mentioned, eosin is good for showing the general forms of the masses composed of spherules. (See Figures 124, 125 and 126.) The gentian violet is a selective stain and shows the structure of the larger masses of spherules. (See Figures 131, 132 and 133.) This structure is made up of several kinds of spherules, i. e., spherules differing chemically, and because of these individual differences, take and hold the stain differently and show the individuality of certain similar spherules by similar stains or differentiations by different degrees of color. Some of these stain very brightly, some assume a dull color, and others only enough to show their outline. It is, therefore, a very valuable agent. Many of the larger masses are shown by this stain to be built up of minute spherules differ- ing from each other in some chemical character, and yet acting together in building these compound forms. They might be called mulberry forms, since they are composed of various little round masses which we may call the primary spherules. These are generally no larger than the nucleus of an ordinary epithelial cell ; so small indeed that they may circulate in the blood stream STUDIES OF SALIVARY CALCULUS. 83 without interference, or probably pass through the glands with the usual secretions, when there is an overplus of the material to be thrown out, or in any other condition of the blood in which these chemical constituents are not retained. The phenomena presented, when viewed in this way, are of wonderful interest. Nigrosin is a diffusive stain for much the greater part of the material, but it has one point of differentiation not made by any other stain that I have tried. There is one class of spherules in many of the specimens — not in all — that nigrosin leaves perfectly transparent. (See Figures 129 and 130.) This spher- ule is often larger than others, or possibly made up of many smaller spherules, none of which take the stain, and therefore are invisible. In very thin deposits, one of these is often the center of a cluster of other small spherules which take the stain. This causes them to appear as if formed around an opening. In thicker deposits these — which seem to have been the first deposited — often peep through among the darker ones, by which they are nearly covered, as tiny stars of clear light, or as larger areas of light where they have less covering. This makes nigrosin a very interesting stain. It is curious to note the greater variations in markings brought out by these differ- ent stains, and the demonstrations of differences in chemical preferences by spherules which are thrown out of the circulation together and so intimately associated. Perhaps some other per- sons more familiar with the modern methods of handling stains and mordants, and also with more time at command, would be able to produce other differentiations which I have not found. The differentiations mentioned are represented as well as pos- sible in plain light and shade in the series of photomicrographs presented. They are, however, a very poor representation of what is actually seen with the microscope. This staining of these different globulins, which make u]) the agglutinin of salivary calculus, is not different in theory or in what it teaches, from the staining of tissues when properly prepared, cut in fine sections and then their different parts brought into bold view by selective stains. The epithelial cells stain differently from the connective tissue cells. In each of these again, the nucleus stains differently from the body of the cell. In each case, the differential stain is a response to chem- ical preference — an exhibit of chemotaxis founded upon a chem- ical difference in the particular portion of tissue. These selective stains of the spherules of agglutinin show conclusively that this subst;inc(^ is made u]) of <-i iniinhei' of glob- 84 SPECIAL, DENTAL PATHOLOGY. ulins wliicli differ in some particular features of their cliemical structure. We can not from these, select and name the globulins represented. It seems best, then, that we continue to call this mass derived from the saliva the agglutinin of calculus. Deposits classified. I have previously spoken of three classes of deposit. (1) Agglutinin of salivary calculus loaded with calcium salts, and of a greyish-white color; the central zone. (2) A considerable deposit of the same agglutinin, so far as I am able to determine by physical, microscopical and staining tests, which carries with it very little of calcium salts. When very fresh, this is semi- transparent or slightly greyish; the middle zone. (3) A still more scant deposit, fully transparent, which in staining tests seems to lack certain of the classes of spherules of the agglu- tinin present in the other two forms; the outer zone. Those spherules which stain brightly with gentian violet are missing in the outer zone. It is possible, however, that the presence of the calcium salts may so affect the staining as to be deceptive on this point. These zones are shown best in Figures 126 and 131. These three zones are usually present in the material laid down in each paroxysm; the greyish- white deposit occupying the center of the area, surrounded by the semitransparent or middle zone, and still farther out by the transparent or outer zone. These differences are not usually very sharply defined, but grade imperceptibly into each other. The central, or grey- ish-white, form is never seen alone, but is surrounded by the other two. The semitransparent and the transparent zones are often seen without the greyish-wbite zone. Not very frequently the transparent zone is seen without either of the others. Paroxysmal, characters. While I was studying the masses of calculus by aid of staining agents, other studies were also being carried on. One of the first determinations certainly made was that the deposit of salivary calculus is paroxysmal. AVith myself, and others in good health, whom I have had the opportunity to examine suffi- ciently for a determination, there has been no exception to this rule. Some persons, who were in a very low state of health, were regularly examined by others, and reported as having a deposit every day on plates worn. Tbis deposit was of the semi- transparent and transparent agglutinin of calculus, but none STUDIES OF SALIVARY CALCULUS. 85 of the greyish-white form, containing calcium salts. These per- sons may have paroxysms of the deposit of the white form. This point needs further investigation. For a considerable time the cause of these paroxysms of deposit eluded me. I instituted the most rigid scrutiny of my own actions and doings — how I was employed, how I slept and what I ate. For some time I weighed the food eaten at break- fast and dinner and took notes of my noon lunches at the res- taurant. The plan of study was not long in bringing results. It was found that palatable meals, eaten of heartily, and apparently well digested, were followed by paroxysms of deposit of salivary calculus. (See Figures 131, 132 and 133.) These meals did not produce any notable discomfort, but after studying the matter more closely, I found there was something of a heaviness and languor following such meals, but nothing more. One of my students, a jolly and rather fat fellow, expressed the matter in this way. He told me that after hearing my lecture on this point, he concluded he would try it himself, for he had to have calculus removed from his teeth very frequently. He said he ''cut his meals in two in the middle." He didn't get hungry, he didn't lose flesh, he didn't have any more calculus on his teeth. *'But," said he, 'Hhat isn't half the story. Before trying this out I was absolutely unable to read or study for more than one hour of an evening. I would go to sleep in spite of everything I could do. But now I can work from eight to eleven every evening and feel good all the time. No more big meals for me." When this matter was determined, I stopped the paroxysms of deposit in my own mouth completely, except as I produced them in the study of the effect of d.ifferent articles of food. Or, if I wanted a fresh deposit of calculus for study, I was able to get it. If I went to my restaurant and ordered boiled pigs' feet and sauerkraut and ate the full order served, I was sure of a flood of calculus within three hours, which might continue several hours. If I ordered the pigs' feet and sauerkraut and ate but half the order served, I had no calculus. Braised meats of any kind, with rich brown gravy, eaten heartily, usually pro- duced a paroxysm of deposit, but if eaten more moderately produced no such effect. I can drink one glass of milk before retiring at night and rise in the morning with a perfectly clean plate. If I drink two glasses of milk before retiring, I will have a good specimen of calculus next morning. The kind of food seems to make veiy little difference, an excessive amount of 86 SPECIAL DENTAL PATHOLOGY. almost any food produces a deposit. I found that I could induce a paroxysm of dei^osit with almost any good nutritious food, even simple bread and butter. One day for luncheon I ate two-thirds of an order of ' ' baked young pig and sweet potatoes." When I returned from lunch I was more careful than usual in cleansing my plate. This was at two o'clock. During the afternoon I was busy with other things and forgot the matter. That evening a few minutes after six o'clock, I examined the plate and within these four hours, a flood of calculus had been poured out, which covered up and hid my trap completely and filled both buccal sides of my plate nearly to the cuspids. All of the central zone was almost snow white. I cleaned the plate carefully and ate my dinner. When I stopped writing at midnight the plate was found to be clean. It was also clean next morning. This paroxysm with its extraor- dinary amount of material had come and gone within the four hours after eating. Curiously enough, the more I study this ]ioint regarding the duration of paroxysms the shorter I find them. Gathering calculus direct from the parotid gland. In order to determine definitely that calculus comes into the mouth as calco-globulin, I instituted another series of experi- ments. Saliva was collected before it reached the mouth by the intubation of Stenson's duct. Special apparatus was designed for the purpose: a tube was passed into the duct and the saliva was collected in a test-tube, without ever having touched the tissues of the mouth. (See Figures 135 and 136.) A test of the saliva so collected, by placing it in the incubation oven, showed it to be sterile. I selected two young men, who frequently had calculus on their teeth, and took them out to luncheon. I gave each of them a plate with two whole pigs' feet which had been boiled with cabbage, and they were invited to eat anything else they wished. The pigs' feet had been boiled until they were soft and tender. Of the two young men in the first group that I employed for this purpose, one of them ate all of his order, g-nawing the bones clean. The other picked out certain bits, and did not eat more than one-fourth of the order. About two hours afterward, tubes were put into the ducts and the saliva was found to run fairly well. AVe will call these two men A and B. In three-quarters of an hour 8 cc. were collected from A and 6 cc. from B. STUDIES OF SALIVAEY CALCULUS. 87 Cover-glasses for catching the deposit were |)laced to the bottom of the test-tubes before beginning the collection of the saliva, and remained there. As the running of the saliva con- tinued, it was noticed that in the case of A, who ate the full amount of the order of pigs' feet, the saliva was turbid in the tube; in that of B, who ate only a part of the order, it was clear. A little later, in the saliva of A, a deposit of snow-white calco- globulin could be seen upon the cover-glass in the bottom of the tube; in that of B, toward the close of the experiment, there was some deposit on the cover-glass, but it was vevj slight. The saliva in the tube remained clear. At the end of three-quarters of an hour the experiment was discontinued, believing that we had enough to make a good test. The tubes were then set away. I did not put them in the incubation oven, as the weather during the day had been 98° in my room, making the room itself an incubation oven, and it remained so through most of the night. The next morning T found the saliva clear in lioth tubes. In that of A, a snow-white deposit was piled up on the cover-glass — all that would lie on it. The cover-glass was % inch in diameter and was piled up fully 1/4 inch high from the 8 cc. of saliva, only 7 cc. of which were above the cover-glass, and the space under the cover-glass was well packed with calco-globulin. In the tube from B there was a very good microscopic specimen of calco-globulin on the cover-glass, but no great accmnulation. Any one may make the tubes and conduct a similar series of experiments. The ducts should be examined in each case before anything else has been done. In quite a number of per- sons, Stenson's duct was found to be so small that a tube, the lumen of which was large enough to serve the purpose well in collecting, could not be passed into it. In others, the duct was so tortuous that it was exceedingly difficult to follow it with a tube to sufficient depth for the tube to hold well. Many diffi- culties arise which must be overcome. Persons must be selected who are known to have considerable deposits of calculus, and it should be determined that the tubes may be passed into the ducts. Then they should cat a heavy meal of food that is highly nutritious and easily digested, for the purpose of arousing a paroxysm. The tube should be inserted about one and a half hours after the meal and observed carefully in order to catch the paroxysm at its height, for it is not uncommon for these paroxysms, with a great flow of calculus, to be over in half an hour after they begin. 88 SPECIAL DENTAL PATHOLOGY. The gathering of calculus in this way marks a step in advance in our study of tliis deposit, one that will stand for all time, showing whence comes the calculus that we find upon the teeth. In the endeavor to collect calculus in this way, a great many failures will occur. We must not take persons who have never been loiown to have calculus on their teeth, and expect to find accumulations in the saliva drawn. We must not expect to succeed in every case, even though we have made the very best possi1)le selection of a subject. If a person's digestion hap- pens not to be good at the time, the food may arouse no flow of calculus, because if the food is not well digested, there will be no excess of calco-globulin. Deposits of hard salivary calculus are occasionally found in the ducts of the salivary glands, the nidus for such deposits usually being some foreign substance, such as a splinter of a wooden toothpick, which has been accidentally passed into the duct. I have seen several such calculi of considerable size. Figures 140, 141 and 142 are actual size reproductions of photo- graphs of calculi removed from the ducts of the salivary glands. There is also shown in Figure 143 a tremendous deposit which was found in a kidney of a cadaver in the anatomical laboratory. Globulin. A globulin is any one of a class of albuminous proteid com- pounds insoluble in water or alcohol, but soluble in weak solutions of the neutral salts. The animal globulins include fibrinogen, serum globulin or paraglobulin, globin, myosinogen, ciystallin, and vitellin. This definition was written after con- sulting a number of medical and general dictionaries, but is not quite like any one of them. I have been unable to determine definitely why this term glo1)ulin has been applied to these products, but must suppose that some one has seen the spherical forms, and consequently applied the term globulin. Globulin is recognized by physiological chemists as a highly nutrient material held in the blood, body juices and flesh, in readiness for use in tissue metabolism of the constructive type; a nutrient material in excess of immediate needs, but ready for immediate use. In this respect the globulins are very important in the nutritional processes. As previously stated, in this method of procedure the agglutinin of calculus is found to respond to the usual tests for glol)ulin. 'W\ p^"^ * V > ' it IF *■. « i.Hi- .N «^ .'*^*i*:S ^ ' w-". *^^^rew^^Mlk V >'*■, ^^M 12"'' *'^ tt i.^ JS BBJf Vf ii6 r?»i« .^ i^il^-.^ Fig. 131. Fig. 131. The appoaranco given by an accnnuilation rai)i(ll.v i"ornic«l (witliin four hours), stained with gentian violet, after having been coagulated by i)hen()l. '^ \)or cent, solution in water, and the uncombined phenol carefully disstdved out by repeat«d washing. The lower right-hand corner uf the picture was in a conii-r of the frame. It will be n )ticed in this that certain of tlie snialier splieruics stain uuuc promi- nently than others, and that the larger spherules are agglomerations of the smaller spherules. This sj)ecinu'n was jicrfectly transjiarent before coagid.-ition with phenol. At certain points the accuuudation was too thick for photography. 10 Fig. 133. Fig. 132. Appearance given by an accumulation forming in about ten hours, stained by gentian violet after it had been exposed to 4 per cent formalin for one hour, and repeatedly washed to remove nneombined formalin. It remained in tlie staining solution twenty-four hours, and was washed in absolute alcohol, which was repeatedly changed, and much of the time kept in motion for about two hours. This specimen gives a beautiful appearance when seen in the microscope, but as the stain is a bright blue with gradations of the intensity of color in the different primary spherules, it is only imperfectly represented by photography. The conglomerate structure can, however, be made out fairly well. Fig. 133. From the same specimen shown in Figure 132, showing only the central portion of the field. In this a multitude of fine spherules that take the stain sharply appear in the make-up of the large spherules. In some specimens the masses are made up of primary spherules that take the stain differently, showing distinct chemical differences in these primary spherules that join in making up the larger compound forms. Thus far this is well shown only by the gentian violet stain, following formalin as a mordant. Other stains may yet be found that will make these selec- tions and be better for photographing. studies of saltvaby calculus. 89 Agglutinin of salivary calculus. As yet the agglutinin of salivary calculus has been but partially studied. I have given attention for the most part to the physical phenomena rather than the chemical qualities. At present the former are much the more important qualities to be made out. When a substance which is well known is identified, that is sufficient. What it does in the new position in which it is discovered becomes the important question. I have adopted the term agglutinin or agglutinin of calculus because we should have a distinctive name for the substance as it appears in con- nection with deposits of calculus, to distinguish that form from every other, no matter what it may be chemically. That it comes into the mouth with the saliva there is no question. Agglutinin, as we find it deposited in the mouth, when taken up in the fresh state — as a deposit discovered while being laid down during the day, or one discovered in the morning, having been laid down during the night — is so much heavier than water that it will sink at once. It will do the same in fresh saliva. It is probably not in actual solution in the saliva at all, but is dis- tributed in the form of very small primary spherules. From these the larger masses seen in deposits are built up. (See Fig- ures 123 to 128.) It now seems that there can be no question that it is deposited directly from the saliva almost immediately upon entering the mouth. The bulk of the material thrown out is carried away with the saliva and is never seen. It requires especially favorable conditions for it to become deposited in the mouth, upon the teeth, or even upon hard sub- stances, as plates, worn in the mouth. As will be mentioned later, it was found that deposits did not occur on a cover-glass held in place with a gold frame, unless the frame was made with an angle or rough edge which would give opportunity for the first deposit to occur. A study of the deposits occurring on artificial dentures shows that the beginnings are also in sheltered places. This should lead to the making of more perfect denture forms so that deposits will not occur. Consistency of the spherules. These spherules are very soft when gathered with the saliva and allowed to fall upon a cover-glass fixed in the bottom of a test-tube to catch them. They will accumulate and pile up on the cover-glass until after a time they will roll down the sides of the pile and over the edge of the glass. A little disturbance will cause them to roll off as they accumulate upon the glass. If the tu])e is ko])t still, how- *io 90 SPECIAL DENTAL PATHOLOGY. ever, they will, in the course of a few hours, become attached to the glass as Avith a very soft, sticky wax. (See Figure 137.) This waxy consistency in the spherules is very characteristic, for it is by this that they take hold and adhere to hard sub- stances, which form nidi for the gathering of calculus, as the teeth, plates and various hard substances placed in the mouth, or any object that is put in the urinary bladder and serves as a nidus. Once I found a small pen-knife in the urinary bladder of a girl, which had acted as a nidus and was encrusted with calculus. Anything of this kind, or sometimes a group of dead cells, seems to act as a nidus. The peculiar characteristics of the globulin spherule are such as to cause it to cohere in this way, one of its sides flattening down upon hard substances; hence it gathers on teeth, plates, etc. From this description it will be noted that the original spherule, as eliminated from the salivary glands, or other sources, is a very soft mass that will not stand alone and pre- serve its rotundity, if laid upon a flat surface, but will slowly come to stick fast, and change its form, presenting a flat side upon the substance to which it sticks. Others, each falling upon a layer of these, will stick to them, and so on until a very con- siderable accumulation may be built up. The building of these depends very largely upon the sticky character of the spherules. We may get special preparations in the following way: While the saliva is still running, place the point of a small glass pipette into the liquid which has accumulated in the test-tube, and draw some of it into the tube of the pipette. Place the pipette so that it will be perpendicular with the point on a cover- glass, and let it stand for some little time to permit the spherules to sink to the point. Then slight pressure upon the rubber bull) will cause a little of the liquid to issue, in the form of a drop, on the cover-glass. Preparation should have been made before- hand, and this should now be placed in a moist chamber, to prevent drying, and should remain there several hours, in order that the globulin may become stuck fast to the cover-glass. Then it can be passed into alcohol, or into staining fluids, and handled so as to make the preparation such as is desired for mounting. To gain some idea of the consistency of these spherules, one may imagine spherules made of a soft wax, warmed until it becomes so sticky that the spherules will first cohere and then gradually coalesce. Each will sink in among the rest and gradu- ally lose its identity. In settling down, there is the tendency to form larger rounded masses. This is apparent on examining STUDIES OF SALIVARY CALCULUS. 91 the material stained on cover-glasses. Some of these are in the form of more or less flattened spheres. As to softness, the spherules which contain a large amount of calcium salts seem to be just as soft, or if anything a little softer, than those spherules which contain no calcium salts, so far as the eye can detect. Globulin and salts inseparable. The spherules containing calcium salts are in no sense hard calco-globulin, but they seem to be chemically combined nevertheless. The one can not be dissolved without dissolving the other. It may be possible to dissolve the globulin and precipitate the salts by the addition of chemicals, but in everj^ attempt which I have made to isolate the salts from the globulin without adding chemicals, the whole body has been dissolved, salts and globulin. I tried hot water, and after five days, six hours per day, at a temperature of 206° F. — 209 is the boiling point at our altitude, barometer 30 (sea level) — a solution was practically complete, only a very scant waxy deposit remained. Practically the whole material became hydrolized and on evaporation formed ciystals not resembling the crystals of calcium phosphate. No precipitate of calcium salts was discovered ; no amount of mechanical agita- tion seems to succeed in shaking out a precipitate of calcium salts from the soft deposits of calculus. Deposits during illness. I have also discovered another feature of this deposit which is very interesting, though not well worked out. A dentist, who was interested with me in the study of this subject, reported that the full artificial dentures worn Iw his wife, who was a paralytic, were covered with a thin veil of the transparent zone of salivary calculus every day. It was necessaiy for liim to clean these dentures, as she could not do so, and he examined them carefully each day for a considerable time. If the cleaning was neglected for a few days, the deposit was considerably thickened and became of a brownish color and the cheese-like consistence. In this way she seemed to be losing by leakage through the secretion, so to speak, the scant supply of globulin which was formed by her very imperfect digestion of food. In 1912 I spent three summer months on my farm under what seemed to be ideal conditions for recovery from a neuritis. I slept in a bungalow, the walls of which were made of screens, except a dressing-room and a bathroom. Practically, we had our meals, lived and slept in the open air. I also spent most of 92 SPECIAL DENTAL, PATHOLOGY. the time of daylight in the woods directing some lahorers. T was taldng about as much out-door exercise as my condition would allow. During this time I had much more deposit of calculus than when at home pursuing my usual work. That is, a deposit seemed more easily aroused. This was a surprise, and I watched it very carefully and made the best comparison I could with my consumption of food. While this influenced it sharply, a deposit was much more easily aroused than formerly. After my return to my usual employments, this condition ceased. I do not know why. This circumstance, taken with what we see among our patients, seems to confirm the supposition that there are some systemic conditions which favor the deposit of calculus, besides the quantity of food taken. In this we must remember also, that there are many people who never have a deposit of calculus upon their teeth. Yet, so far as we can see, their habits of living are the same as those of other people. They are not ditferent in physical qualities nor in degree of general health. In the consideration of the deposit of calculus this must not be overlooked. It speaks very emphatically of a calculus dyscrasia of which we have as yet no tangible idea. A few times I have seen the deposit of agglutinin in the clear form so abundant that while it did not appear to the eye in its clear, transparent freshness, it would hide the plate com- pletely when coagulated by boiling water, in which it would be whitened and become opaque. A deposit of this extent is evi- dently quite rare, but I have seen it several times. It has occurred a few times on my own plate, in conjunction, however, with a whiter deposit about the openings of the ducts of the glands. This, with myself, has always occurred during some illness. (See Figures 138 and 139.) In passing, I may mention the fact that not infrequently calculus is found on bullets and other metallic substances lodged in the flesh, which have remained for some time. This calculus as I have examined it, particularly on lead, has been softer than the calculus formed in the saliva or in the urinary bladder. In some specimens it has been so soft that I could crumble it with my fingers, and yet there was no doubt whatever of its character. This shows plainly that calculus may also be deposited from serum exuding from the tissues, and is therefore carried by the blood stream. Tig. 134. Fig. 134. A slight but vory diffuso deposit oeeiirring slowly at tlio ending of a paroxysm. There is a sprinkling of sphernles thid take the stain sharply, among many fine sphendes that do not, and a considerable ninnl)er of small eircles scattered over the field formed by accumulations around spherules which do not take the stain. 10b Fig. 135. Fig. 135. Intultulinii of Stfiisoii's duct for tho purpose of eollcctiug the saliva as it comes from tiie parotid gland. A silk ligature, previously tied around the brass tube, is tied to a bicuspid tooth to hold the tube in the duct. A brass wire is so bent as to hold a disk crosswise of the test-tube. This disk supports a cover-glass. (See Figure 136.) As the saliva, which drops from the brass tube, accumulates in the test tube, it will be cloudy if it contains much caleo-globulin, and the spherules will gradually settle and collect upon the cover-glass. (See Figure 137.) Fig. 136. Fig. 137. Stciisnn's (liii't. This liy;atiire is t from slii)ping IKisition ill tost- FlG. 136. liituhiifioii set for confctiiijj s;ili\:i direct froii A, C'amila for iiitubatioii tul)o. b, Tube witli siliv lifjatiirc attaclu-d. tied to a l)ieusj)id toolli after the tube is in the duct, preveutinjr out. c, Wire witli disk attaciied, to hold cover-gia.ss, d. in li(.ri/.oiit;i tube. E, Test-tube for collecting saliva. Fig. 137. Eepresentatiou of the test-tube with saliva containing calco-globulin. The saliva is at first cloudy and gradually clears as (he sphendes settle upon th.> cover-glass. In exc(>ssivc pjiroxysuis the spliciulcs will jdle uji on the cover-glass until it will hold no niorc and then roll olV :ind accumulate iti tlic bottom of the test-tube. '7 » V' ' Fig. 138. Fig. 138. This is a deposit of a peculiar tyiK- that seems not to contain calcium salts, but will form a cheese-like accumulation on the teeth or on dentures. When cleaning is neglected for a few days, this becomes too stiff to be removed with a brush, but may be scraped off with the finger nail. This form has been observed oftenest on dentures of persons whose nutritive powers are very low. It is very persistent in some confirmed paralytics. It has not, however, been sufficiently studied. Nigrosin stain. Fig. 139. This shows a deposit of finer spherules of a type of material similar to that shown in Figure 138. Nigrosin stain. STUDIES OF SALIVARY CALCULUS. 93 It has been with some difficulty that I have arrived at the conclusion that so important a nutritional substance as the globulins are shed out with the secretions and become a prin- cipal factor in the production of such a substance as salivarj- calculus, but the facts recited force this conclusion. I do not know how many persons in very poor physical con- dition are having such deposits as have been mentioned, or are losing the globulin from their blood in this way. My finding, however, is a strong suggestion that this may be a mode of draining away the nutritive power of the blood in such con- ditions. Chemistry of the deposits. The chemistry of these deposits needs closer investigation. It seems now that the following supposition may be foimd cor- rect : The greyish-white, or central zone, of the deposit is com- posed, in the main, of a semifluid calco-globulin, but has mixed with it more or less primary globules not containing calcium salts. The mixture of calco-globulin within the mass becomes thinner as we proceed from the center outward, until at some certain point we have globulin only, as found in the outer or transparent zone. Physical examination of the mass denotes this change and also the observation of the hardening process shows the two parts to act differently. The white portion will partly decompose, leaving a stony, hard calculus, while the clear portions will harden first to the consistence, but not the color, of cheese, and finally break up and disappear. It is at first slightly yellow, almost transparent, and becomes opaque and of a darker color as it grows older. Whether or not the lactic acid formed in the mouth has any important action in the removing of calcium salts from the more thinly scattered deposits, and, in this way preventing the hardening, may be mentioned as one of the undefined chemical problems of minor importance. Whatever the full truth may be as revealed by future dis- covery, the fact will remain that in the ordinary paroxysmal deposit of persons in good, or fair health, the three zones of deposit will appear, varying widely in the proportions of each. The deposit close about the opening of the ducts, the central zone, carries the bulk of the calcium salts. A condition of general deposit of calculus, about practically all of the natural teeth, is, however, occasionally seen. These are generally neglected cases in which no effort has been made to keep the mouth clean. In such cases, it luis seemed to me 94 SPECIAL DENTAL PATHOLOGY. that there is established a condition of putrefactive decomposi- tion which acts as a preventive of the formation of lactic acid, or neutralizes the lactic acid formed. The study of these changes presents the opportunity for some chemist to do an important work. Hardening of salivary calculus. The chemistry of the hardening of salivary calculus seems to have no literature. That it is deposited in a soft condition and slowly becomes hard, is stated by many writers. With that statement the subject is dropped. ^ I have only begun some investigation of this process from the physical side. The hardening is found to be accompanied by putrefactive decomposition of the agglutinin during which the transparent portions, as well as the white zone, first become opaque and yellow, diminishing very much in bulk. If the speci- men is placed in clear water, this soon becomes clouded with a growth of micro-organisms. Then the changes seem to go on much slower, although apparently of the same character, but the change to the hard, stone-like form, such as is found upon the teeth, does not occur. Ordinarily it is very difficult to follow this process with any degree of accuracy in the mouths of patients. It is also proving to be a difficult matter to contrive artificial conditions which will serve much better. It seems probable now that the hardening can not be studied by any arti- ficial method out of the natural position in the mouth. I have placed a number of specimens in water at room tem- perature and some at body temperature. The results were similar in both. Within a short time the water became white from the growth of micro-organisms, which continued for a week or two. Then the fluid became clear. During this time the deposit lost perhaps three-fourths of its bulk. What remained had not become hard. One very heavy white deposit was placed, plate and all, in clean water and closed with a close- fitting lid, but not sealed. At the end of four months what remained of tlie mass was of a yellow color and so soft that I could pick it to pieces with the small end of an ordinary wood toothpick, finding only an almost imperceptible resistance. Still more recently, I have packed masses of the fresh soft deposit on a cover-glass and suspended it by a clutch fastened in the cork, and corked it tightly in a short glass tube one inch in diameter. In the bottom of this tube was placed a piece of cotton with as much water as it would hold without being liable to run. This specimen was taken from a very thick paper-white STUDIES OF SALIVAKY CALCULI'S. 95 deposit. At the end of the second day it was much too hard to brush away; in five days, yellow and softer. It did not harden as is the mouth. Knowledge of hardening basis for prophylactic teaching. The meaning of a wider knowledge of the deposit of salivary calculus in its relation to prophylactic work can hardly be reckoned. This should stand as the basis of much of the popular teaching of prophylaxis. Our people should learn the facts in brief, substantial statements, accompanied with equally definite statements as to how to deal with them. Deposits of calculus of any degree removed twice per day — morning and evening — will do no harm whatever to the gingivae or to the teeth. All people, with but a few exceptions, should be able to so conduct their food habits that no deposits of calculus would occur; or, l^y cleaning after each meal, calculus may be prevented from doing harm to the tissues. Explanatory supposition. The facts here stated give origin to some suppositions that seem necessary to a fuller explanation of the method of the instigation of the paroxysms of deposit of this material. The most rational supi^osition which has come to my mind is this : With a very full meal of highly nutritious food, with the alimentary apparatus in good condition, much more nutrient material is thrown into the blood, and more of the globulins are formed than are necessary or can be used. At a certain, or, perhaps, variable overaccumulation of these, the excess is shed out with the secretions and excretions, and then a proper equi- librium is again established. This marks the rise and decline of the paroxysm. This is at least a thinkable explanation of a process, as yet hidden, which seems to meet the now known facts and affords a resting-place for thought regarding the most common form of paroxysm which l)egins, rises to its flood, abates and ceases within from one to three or four hours. It is rather rare that I have seen closely watched paroxysms of much longer duration. I have seen a number which did not continue for more than half an hour. A much closer watch than had at first been made, has convinced me that paroxysms lasting two or three days, as I have heretofore stated, have been two or more paroxysms in close succession instead of a single parox- ysm, as I had supposed. This statement has in view persons in fairly robust health. 96 SPECIAL DENTAL PATHOLOGY. In order to keep this closer watch, it has become necessary to clean off some portion of surface receiving deposit, or a cer- tain part of the trap itself, every hour, or even every half hour, until no more deposit is discoverable. In persons in chronic ill health, and especially those whose condition is that of marked malnutrition, an almost constant slow deposit of agglutinin seems to occur. This may not carry with it any deposit of calcium salts. In that case it does not harden as do other deposits, but settles into a curd-like mass which strongly resists removal with the brush, but may readily be scraped away. This form of deposit never becomes very hard. The material, however, gives the same appearance in stained specimens as that containing calcium salts. This form of deposit of agglutinin sometimes creates a very foul condition of the plate and mouth through the putrefactive decomposition which occurs in the mass. A low form of inflammation of the soft tissues occurs wherever this decomposing material is in contact with them. In the class of cases just mentioned, the opportunity for the careful daily observation of many persons has not occurred to me, but daily examinations have been made by others and reported to me. From what I have learned, it would seem that the nutritional process is so low that much of the small amount of the globulins formed are leaking away with the secretions and excretions, and these are being lost. This condition acts to intensify other diseased conditions, or may occasionally form the basis of a type of wasting disease. Calco-globulin in other secretions. I have not yet examined other secretions than the saliva for globulin. The literature gives but little information on the subject. It seems to me probable that during certain hours after heavy meals other secretions will be loaded with globulin the same as the saliva. These would give a deposit of calculus if a nidus happened to be present, as occurs in the urinary and gall bladders and at some other points. Calculus in the urinary bladder has a wide literature, but at present this does not help us. While we find many matters dependent upon these deposits very ably and fully discussed, the intrinsic part of the sul)ject seems to have had no very care'- ful examination. Fig. 140. Fig. 14]. Fig. 142. Figs. 140, 141, 142. Reproductions of salivary calculi removed Iroin ducts of salivary glands. Actual sizes. Specimens from JMorthwcstern University Dental Museum. Figure 140 presented by Dr. Edward C. Tyler, Traverse City, Mich. Fig- ure 141 by Dr. W. R. "Wolf, Parsons, Kan. Figure 142 by Dr. P. A. Pyper, Pontiac, 111. It should be particularly noted that these deposits occurred from the saliva before it reached the mouth. 1 1:'.. Fig. 143. An enormous deposit of calculus in a human kidney. Actual size. This specimen was found iu a cadaver in the anatomical laboratory of Northwestern University Dental School, by Dr. William Bebb, curator of the Museum. It seems probabh'that renal and all other calculi are closely related to the salivary calculi, and that the eaiise of all is the same. STUDIES OF SALIVARY CALCULUS. 97 Globulin urea, however, has something of a literature. I quote the following from a pajoer which I read before the Chicago Dental Society in January, 1912.* "In general medicine it seems probable that much useful information of importance in diagnosis may be derived from a study of the elimination of the globulins. How and where, for the most part will be determined by trial, or in other words, a general study of the subject as it appears in the secretions, and especially in the excretions. Already globulinuria has a con- siderable literature, though the knowledge of it seems to be rather indefinite. ''In an article entitled 'Euglobulin Reaction in Urine,' by Arthur R. Elliott of Chicago, in the Illinois Medical Journal for November, 1911, p. 520, the progress of this literature is cited. There is also a discussion of the difficulties of diagnosis between albuminuria and euglobulinuria, a matter which is very liable to confusion by the close resemblance of the chemical reactions of the globulins to albumin. ''From what has been said of the deposit of globulins in the form of agglutinin of calculus, one would expect the appear- ance of the globulins in urine to be transient. This, in fact, is what seems to occur, and these have been referred to as inno- cent albuminurias. This article by Dr. Elliott is worthy of study for both its citation of authorities and its discussion of the means of differential diagnosis now known. "If the physician could command the time to learn to dis- tinguish readily the paroxysms of the deposit in the mouth, he would probably find a coincidence between this and the innocent albuminurias, and that each is an expression of the same sys- temic condition. It is possible that the careful comparative study of the saliva and urine may lead to clearer definitions and simplify the means of division of the grave and the innocent albuminurias. "But are these repeated paroxysms of elimination of globulins innocent of injury to health? May they not have a causative relation to some grave conditions, or a harmful rela- tion to more or less grave conditions now not fully understood? It opens up a very wide field for question and investigation. "The examination of the saliva and other secretions, in conjunction with the urine, seems to be demanded." Dr. Henry H. Burchard makes a quotation in his paper on * " Deposit of Salivary Calculus," by G. V. Black, Dental Kevicw, Vol. l2G, 1912, p. 337. 11 98 SPECIAL DENTAL PATHOLOGY. the Origin of Salivary Calculus, Dental Cosmos, 1895, p. 828, from a conversation Avitli Dr. E. C. Kirk, in which Dr. Kirk is quoted as saying: "I believe all of these calculary deposits will he found to belong to one great order. That salivary calculi will be found to be one group of several chemical bodies which are formed by the precipitation of lime salts in colloid media, and this is the common factor in the formation of calculi in general. That about a nidus these substances will be deposited, or form in some definite manner ; that they are more than mere agglomerations of lime salts with extraneous matter; that they resemble calco-globulin more than they do mere cemented pre- cipitates, and I believe all calculi will have a family similarity in general structure, no matter in what part of the body they are found." In this conversation, as reported here. Dr. Kirk's remarks were probably much wiser than the facts then known would seem to justify. The sections of calculus do not reveal a material that seems to be in any wise akin to that which we find in teeth, in calco-spherites in the dental pulp, or in the phleboliths found in the veins, or in those tiny globules thrown down from albu- men solutions which contain calcium salts. It will be recog- nized that this material appears in a very different physical state from the calco-spherites deposited from colloid material as reported by Rainey and others. In the consideration of calcification within the pulp chamber I refer to the very inter- esting work of Rainey and Ord and show two illustrations of nrtificially formed calco-spherites. (See Figures 338 and 339.) My recent search for the actual precipitate, so long regarded as the basis of this deposit, has failed entirely to show the occurrence of any such thing. Neither have I been able to isolate a precipitate of calcium salts by any means I have yet tried. When I have dissolved the globulin, the calcium has also dissolved. Conclusion. I am slowly, by each successive step, being driven to the conclusion that the thought of a precipitate of calcium salts from the saliva so long held, by myself and others, has been a myth. It seems now that calculus comes into the mouth as a finely divided calco-globulin which collects in masses on hard substances and is finally, with the decomposition of much of the colloid elements, hardened into stony calculus. INFLAMMATIONS DUE TO SALIVARY CALCULUS. 99 GINGIVITIS AND PERICEMENTITIS DUE TO DEPOSITS OF SALIVARY CALCULUS ILLUSTRATIONS: FIGURES 114-170. The injurious effect of the deposit of salivary calculus upon the teeth has been known since the eariiest historical times. It has always been regarded as a deposit from the saliva. The calculus is deposited upon the teeth, never upon the mucous membranes or other soft parts. It is, however, the soft tissues which are injured — not the teeth themselves, except as they lose their soft tissue and bony investment. Being deposited upon the teeth, the calculus, having become hard, impinges upon the soft tissues and causes them to become inflamed and red, to bleed easily, and to become involved in suppurative processes. Gingivitis. Beginnings and eaely progress of deposit. The place of first deposit is usually on the buccal surfaces of the molars, or the lingual surfaces of the lower incisors. In both localities the deposit is close to the margin, or crest, of the free gingivae and appears first where there is a blunting or thick- ening of the free gingivae, forming a little shelf which invites the lodgment. (See Figure 144.) In many cases, however, the deposit spreads from these points and may include all of the teeth. When the deposit begins at the crest of the gingivae, the tendency is to grow in thickness and to spread in every direction upon any parts of the surface of the tooth or teeth that are not kept clean by the rubbing of food over them in mastication, or l)y artificial cleaning. As this goes on, from month to month, the deposit impinges more and more upon the crests of the free gingivae and causes them to become inflamed and bleed easily, as mentioned. As this deposit continues, the gingivae become thickened and shortened very slowly. This greater thiclmess of the tissue gives a broader shelf for the lodgment of more calculus, and a broader covering is deposited over the inflamed tissues. In studying ground sections of calculus with the micro- scope, we find the layers of deposit as it occurs, lapping in under the thickened lower portion of the deposit, and between it and the remaining soft tissue. This is fairly well shown in Figure 100 SPECIAL DENTAL PATHOLOGY. 163. In occasional cases, the deposit will be thicker than the thickness of the gingivae, and will overlap the lingual or labial surface of this tissue. This is most frequently seen to the lingual of the lower incisors, but may occur to the buccal of the molars, or elsewhere. The soft tissue will often remain intact for a considerable time under this overlapping calculus. (See Figures 152, 153 and 154.) Suppuration. The irritation of the investing tissue, caused by the presence of the deposit, and the covering of the deposit itself, offer opportunity for collection and growth of the bacteria of the mouth. Therefore, suppuration of the soft tissue, in con- tact with the deposit, occurs from time to time, destroying parts of the tissue, and this gives opportunity for the deposit of more calculus in the space gained. This goes on, very slowly as the rule, until the free gingivas are destroyed and the deeper tissues are reached. Then these are involved by the suppurative proc- ess as cases progress ; the bone of the alveolar process, the peri- dental membrane and the gum tissue all being destroyed. The products of suppuration and decomposition will often make the breath very foul. Pericementitis. Destruction of the deeper tissues. If not artificially removed, the encroachment of the calculus goes deeper and deeper, involving the crest of the alveolar pro- cess and the adjacent soft tissue. Indeed, the absorption of bone in such areas of inflamed tissue is quickly accomplished. (See Figures 144, 145, 146 and 147.) On examining this tissue immediately after the removal of the calculus, soft granulation tissue only will be seen. A sharp steel probe will, however, show but a slight covering of granulation tissue over the short- ened and apparently thickened stub of the partly absorbed alveo- lar process. In this way, the bony alveolar wall is destroyed, little by little, from month to month, as more and more calculus is added, going deeper and deeper along the root of the tooth to which it clings. All of the investing tissue, soft and hard, is destroyed as this progresses. (See Figures 155 to 167.) Attachment of peridental membrane to root maintained TO level of soft tissue remaining. No matter what the extent of the injury, the attachment of the peridental membrane to the root is usually maintained to the level of the soft tissue remain- ing. (See Figures 144, 145, 146 and 147.) Any considerable accumulation may be broken away from the tooth with suitable instruments, and give a clear view of the process of destruction. Fig. H."). Fig. 144. Fig. 147. FlG.s. 144, 14;j, 14(i, 117. Drawings to illusliatc tlic pr(.nr,.ssiv(" ilcstruct ion of the invfisting lis.sues caused by dejxisits of !-;ili\iiiy ciilculus. Fig. 144 shows a slight deposit oii the liiigii:!! siul'aci' of a lower ineisor whieh iias caused a gingivitis only, not having progressed far enough to involve the att:udi- nient of tlie peridental membrane to tin' cementuni. Fig. 145 shows a similar slight deposit on tlir Imcral surface of an ui>i>er molar. Fig. 14(5 shows a more extensive accunudatiim on the lingual of a lower ineisor than tliat shown in Figure 144. It will be noticed that the gingival line of the tooth has been passed, and the deposit has abnost reached the crest of the Ixuie. Fig. 147 shows a still greater destruction, including also the labial tissues. In all of those it Tvill be noticed that all of the investing tissues — gingiva', peridental membrane, bone and gum — are destroyed on a line practically horizontal to the long axis of the root, and pockets alongside the rout are not formed. *11 Fig. 14S. Fig. 14V Fig. Fig. l.'.i. Fig Fig. l."):!. Fig. l.J4. FiG.s. 14S. 149, l.")i). l."l. Tcftli (if iioriiKil fonii sliowiug extensive deposits of salivary eaiciilus. iSpociim-iis fruiu JSurthwesteni I'liiversity Dental Museum. Figs. 152, 153, 154. Lower incisor and cuspids with deposits of salivary calculus which overlajiped the gum tissue. Specimens from Northwestern University Dental Museum. Fig. 155. Fig. 156. Fig. 15< Fig. 158. FlG.S. 15.'), \r>i\. Liiliial :iih| liiiu,|iil vicwx ,if ii lower incisor to.itli ciitir.'lv enveloped, except purtiuii of crown, by (k'i)<)sit, of «ilivary calculus. No portion whatever of the root can be seen. Specimen from Xorthwestern University Dental Museum, presented l)y Dr. Herbert S. Merdock, Sprinfjcr, N. M. Figs. 157, 158. Labial and lingual views of four lower incisors the roots of which are enveloi)ed by dej)osits of salivary calculus. 'I'iie tuovements of these teeth prevented the deposits on the respective roots from unitin<,r. The proximal surfaces of the deposits arc worn smooth from the labio-iinyual movement of the teeth. Specimens from Xortli western University Dental :\Iuseum. lib Fig. 159. Fig. 160. Fig. 161. Fig. 162. Figs. 159, 160. Mesial and buccal views of an upper second molar with a large deposit of salivary calculus which did not destroy the tissue immediately adjacent to the root above the ginjrival line of the tooth, alliioutrh only a little was spared. This is an unusual form of the deposit. Specimen from Northwestern University Dental Museum, jiresented by Dr. Arthur B. Freeman, Chicago. FiG.S. 161. 162. Two views of an upper first molar witii an cnornHius dejiosit of salivary calculus attached. Si)ecimen from Korthwestern University Dental Museum. Fig. 163. Fig. 163. Photoinicrograph of a ground section of a tooth with a deposit of salivary calculus attached to the root. The section is so thin that the structure of the dentin IS not clear, although tho j^ingival portion of the enamel luav be seen at the top of the illustnition. Something of the lamination of the depos'it as it was gradually bu.lt may be seen. Specimen ground on the author's special grinding machine descrdjed in the Appendix in this book. w ill i Fig. 164. Fig. jo Fig. 166. Fit,. Kj FiG.S. 164, 16."), 166, 11)7. I lliist r;it inns sliowing tlic dcstnictii)ii of the invosting tissues by deposits of salivary c;ilculiis. Figs. 164 and 16.5 are reproductions of radiogra])lis sliowiny extensive destruction of the alveolar process. Fig. 166 is from a plaster cast of a case in uhicli the deposit was nearly as extensive on the labial as on the lingual of the lower incisors. In this case the septal tissues were destroyed by the use of a wooden toothpick, rather than by deposits. Fig. 167 is from a skull. This shows the destruction of the bone, which is especially deep between the central incisors. Specimen from Northwestern University Dental Museum. Fig. 16S. Fifi. IC,9. Figs. 168, ](J9. An \ippcr and a lower ])lat(' witli very heavy iinils ut' salivary calculus. On both of these the greatest thickness of tlie aecuiiuihition is about half an inch. iSpeciniens from rsorthwestern University JJental Museum. Fifl. 170. Fig. 170. A ilciituro sluiwiiig a dciiosit laiil ilnwii in a sinylc paroxysm. A portion of the soft aecunuilation was dislodged at the next meal after the deposit ocinirred, as shown by the spot above the position of the second molar. INFLAMMATIONS DUE TO SALIVARY CALCULUS. 101 The clean, white tooth crown will stand up in the midst of an inflamed, red and bleeding tissue, often showing the naked gingi- val line where formerly the soft tissue was attached. In many- cases all of both the free gingivae and the body of the gingivae will have been destroyed. The rule is that pockets are not formed alongside the roots, although some detachment may occur in the more advanced cases. This is markedly different from the process by which the investing tissues are destroyed in chronic suppurative pericementitis, as will be described later. Pain and soeeness. During the early progress of this dis- ease there is little or no pain. The teeth may become more or less tender in mastication, and the effective work of the teeth in chewing food, also the cleaning which occurs as a result of vigorous chewing, will be diminished, giving additional oppor- tunity for the accumulation of deposits and a corresponding increase of the inflammation. It is only toward the later stages that teeth so affected begin to have occasional attacks of sore- ness. Usually this is not of much consequence and passes away in a few days. This occurs at irregular intei^vals and grows worse as the disease progresses. Toward the last the parox- ysms of soreness become more frequent and are permanently relieved only by the loss of the tooth. When we realize that these periods of soreness occur with tooth after tooth over long periods of time, before the last of them are gone, we must appre- ciate that this disease has, on the whole, caused a large measure of physical suffering. Teeth become loose and are finally lost. As the alveolar process is destroyed the teeth begin to have much motion in the remaining part of their alveoli. This loosening may occur when the bony alveoli are but little more than half destroyed. This is effected by the absorption of that part of the bone next to the peridental membrane, and the lengthening and softening of the fibers connecting the teeth with the bone. The fil)ers are- no longer stretched tightly between the cementum and the portion of bony alveolar walls that are left. The teeth then become very loose and may easily be moved about; yet in an attempt to extract them, they are very firmly held by the elongated fibers of the peridental membrane, as by so many small but strong ropes, and resist actual removal. Finally, however, the remain- ing attachment is so slight that at some time, when a very loose tooth is particularly sore and troublesome, the ])orson will suc- ceed in picking it out with his fingers. In this long and tedious 102 SPECIAL DENTAL PATHOLOGY. way, running from five to thirty years, the teeth are loosened and one by one are lost, until finally the person is toothless. Menace to general health. But this is not all. The mass of decomposing pus and food debris in and about the deposits of calculus, and in the suppurating areas, have continuously been the home of masses of growing bacteria of many kinds, sapro- phytic and pathogenic, which are often a serious menace to the general health. This may be the most serious phase of the con- dition, although it has generallj^ received little consideration, either by patient, dentist or physician. The relation of mouth infections to general systemic conditions will be considered under a separate heading. Variations in the position and progress or the deposit. I have described above the picture of the injury resulting from the deposit of salivary calculus when it runs its course without interference, attacking all of the teeth together, or in fairly close succession. This occurs only in the minority of cases, which have no treatment. AVhile the deposit on the lower incisors and cuspids is seen most frequently on the lingual sur- faces, a beginning may be made upon the labial surfaces also. (See Figures 144 to 147.) Often it occurs that the progress is made mostly upon the lingual and labial surfaces, leaving for a time the septal tissue standing between the teeth almost untouched. Finally the calculus may close in upon the lateral sides of these septi and this tissue will be destroyed. (See Figures 148, 149 and 150.) In the biscupid and molar region, while the principal deposit is on the buccal surfaces, the lingual may become involved, and subsequently the septal gingivae may be destroyed. The lower bicuspids and molars are usually not quite so extensively involved as the corresponding upper teeth. Deposit usually confined to certain teeth. Very gener- ally the deposit will be confined to, or a greater amount of deposit will occur on, some certain teeth. Others will escape for a time, or pennanently. Then teeth will be lost from this cause only in special regions. These are most likely to be the molars, upper and lower, and the lower incisors, sometimes the one and sometimes the other, or both together. Again, some particular tooth, or teeth, other than the groups named, may be attacked. conditions contributing to occurrence of deposit. 1. Calco-globulin must be brought to the mouth by the saliva from the salivary glands. INFLAMMATIONS DUE TO SALIVAEY CALCULUS. 103 2. Deposits usually occur first on teeth near the opening of the ducts from the parotid or the submaxillary and sublingual glands. Taking all cases together, these are the places where the general bulk of the calculus is deposited. 3. Points of depression in the gingivae of certain regions or about certain teeth, the thickening of the crests of the gingivae from any cause, such as mechanical injuries, previous injuries by calculus, etc., may become places of deposit because of the malform. Form which gives opportunity for initial deposit. The controlling factor then is form which gives opportunity. If we suppose that calculus enters the mouth with the saliva and is immediately ready for deposit, the nearest teeth would receive it. This is the general rule, as has been stated. But the teeth of this locality, and their gingivae, may be of excellent form, and will not readily receive the deposit, or the soft deposit may be removed in the act of chewing food at the next meal. Then deposits may or may not occur elsewhere, dejjending upon form which will favor a lodgment. The position of the deposit is determined by some peculiarity of form which usually will, on close study, be found to furnish a place for the initial deposit and shelter it from removal during mastication. This may be an irregularity in the shape or the position of the teeth attacked, or of their gingivae. To produce such a result the deviation from normal form need not be great, but just a slight depression of the crest of the free gingivae and a thickening of its margin, which will furnish a favorable place for sheltering the deposit. I have had occasion to study this matter very closely in forming traps for the collection of deposits for microscopic study. These traps, as has been mentioned, consist of little gold frames fastened with screws to hold microscopical cover-glasses in selected positions on a plate (See Figure 122.) Once I made a very nice trap for a new plate, beveling the angles and care- fully polishing them down to the glass, obliterating the angle of meeting of the gold and the glass, as nearly as possible. No deposit occurred on the cover-glass, although the plate was worn during a number of paroxysms of deposit. I was compelled to restore the angle in order to get a deposit on the glass. An angle or corner, or roughening of the margins of the gold frame, is necessary to give the opportunity for the initial deposit. With such a place of beginning, tlio deposit will build out over the glass. 104 SPECIAL DENTAL PATHOLOGY. Forms of artificial dentures to avoid deposits. This condition should cause us to make a study of the forms of artifi- cial dentures with respect to deposits of calculus. It is quite possible to so make and finish a plate that no calculus will adhere to it anywhere. This requires, first, that all irregulari- ties of surface be avoided; and second, that every part of the plate be finely polished. Every part must be given as nearly a regular surface as possible. All of the embrasures between the curves of the teeth, as these spread from the contact points, should be filled with gingivaa practically as full as these are in the best natural forms. The crests of the gingiva^ should be reduced to a fine knife edge where the rubber laps onto the teeth. This will make a surface of rubber or of gold so smooth that it will not receive agglutinin and, as a consequence, no calculus will be deposited upon it. To keep it so in general usage, is of course another question, but it may be done by frequent repol- ishing. A full upper denture is shown in Figure 168, and a par- tial denture in Figure 169, both of which have very large deposits. Influence of mastication in preventing deposits. Occa- sionally, the influence of the chewing of food in preventing lodg- ments is strongly accentuated in cases in which an exposed pulp causes pain in chewing food upon one side. This leads the person to do all of the work of mastication upon the teeth of the opposite side. Then the teeth of the unused side will receive the deposits of calculus. In such cases I have seen the teeth of the unused side thickly encrusted with calculus on all surfaces, except some portions of the occlusal surfaces which made con- tact with occluding teeth, wliile the teeth of the used side received very little or no deposit, and their investing tissues presented a healthy appearance. A similar condition is occasionally seen on artificial den- tures. If one side is more convenient to use than the other, the unused side will receive and hold deposits, while these will be prevented from accumulating on the used side. Sometimes the upper molar teeth are strongly inclined buccal ly, and the buccal margins stand out over the buccal surface of the lower molars. This prevents the rubbing of the buccal surfaces of the upper molars by food in the act of chewing, and makes these surfaces favorable places for lodgments. INFLAMMATIONS DUE TO SALIVARY CALCULUS. 105 TREATMENT OF GINGIVITIS AND PERICEMEN- TITIS CAUSED BY DEPOSITS OF SALIVARY CALCULUS. ILLUSTRATIONS: FIGURES 171-178. The treatment of inflammations caused by deposits of salivary calculus should consist: first, of the thorough removal of the deposits and the care of the tissues by the dentist until the inflammation has subsided; second, the training of the patient in the means of preventing a redeposit, gradually leav- ing to the patient the principal care of the case; third, subse- quent examinations at stated intervals to criticize the care by the patient and remove any deposits which may have occurred. It has been sufficiently demonstrated that this plan of treatment is dependable. The removal of salivary calculus seems to have been regarded as a thankless and disagreeable operation from far back in the history of dentistry. This has been from two causes. First, dentists have had no confidence in the real efficacy of the operation for more than a very temporary benefit ; second, they have not understood the nature of the deposit, and while they have recommended to their patients that they keep it off their teeth, they have generally done so in a way which showed an attitude of uncertainty as to results. There has generally been no instruction as to how or when to clean the teeth, further than to direct that the brush be used. The movements of the brush in cleaning have only recently received anything like standardi- zation. Under these conditions it is not much wonder that patients have not succeeded in preventing deposits. With the discoveries which my own experimental observa- tions of the last few years have disclosed, all of this should be changed. Indeed, previous to undertaking my recent investiga- tions, so far as I had seen results from the persistent plans of treatment of such cases by cleaning operations pure and simple, it had become fixed in my mind that the successful treatment of inflammations of the gingiv.T, caused by de]iosits of salivary calculus, offered but one real difficulty. That difficulty was to convince the patient tliat a. permanent cure could })e made by the 106 SPECIAL DENTAL PATHOLOGY. cleaning method, and the calculus prevented from lodgment again in harmful quantities. What is now known of the nature of the deposit fully warrants the statement that this may be realized, if the patient will exercise reasonable diligence in the daily cleaning of the mouth in the manner which I will describe. Under these conditions both the dentist and the patient may undertake this work with the feeling that it is well worth the time and the energy put into it. Removal of deposits and caee of tissues by the dentist. The instrumental removal of the ordinary deposits of hard- ened salivary calculus, when taken in time, really offers very few difficulties. The deposit is always in sight; if not directly, it may be seen indirectly with the aid of the mouth-mirror. It is practically never buried under the soft tissues, nor covered up. AVliile this statement is true, I have seen a very few cases in which some salivary calculus extended under the free gingivae. I have also seen the gingivae when much inflamed and swollen, turned outward from the tooth, creating an open pocket which might become filled with calculus. Such cases are much too rare to enter into any calculation for general cleaning processes. However, their possible existence should not be overlooked. It should be understood that deep pockets along the sides of the roots of teeth do not occur as a result of deposits of salivary calculus, and they are not therefore to be considered under this heading. Previous to the removal of the deposits, and as a part of the examination of the mouth, a careful record should be made of each surface of each tooth upon which a deposit is found. A simple and exact method of doing this will be presented later. This record should be the foundation upon which the future conduct of the case should rest. A definite record of the condi- tion of the mouth as to deposits should be the guide for the after care, the training required by the patient and the fre- quency of subsequent examinations. It is of the greatest impor- tance that the patient shall in the beginning be impressed, not only with the serious final results of neglect, but with the fact that there is a definite and dependable system of handling such cases. Instruments and instrumentation. There is no more simple operation in the dentist's field than the removal of deposits of salivary calculus. Since the deposit is practically always upon the exposed surfaces of the teeth it is easily seen INFLAMMATIONS DUE TO SALIVARY CALCULUS. 107 either by direct vision or with a mouth-mirror. A very simple set of scalers is sufficient. Years ago these instruments were generally much larger and stronger than those of to-day, because of the frequent necessity of removing heavy deposits. It was not uncommon for the dentist to use a large chisel, held with the edge against the deposit, while the assistant struck it a sharp blow with the mallet. As our people have learned to better control the deposit by brushing, the sizes of the scalers used for its removal have become gradually smaller. I present herewith a set of six scalers. A similar set may be secured from any dealer in dental instruments. ( See Figure 171.) These consist of one pair of pull instruments, one pair of push instruments, a sickle and a cleoid. These are all that are necessary for the removal of the bulk of the deposits. Their use should be followed by selected instruments from the set of scalers for the removal of serumal deposits, which are smaller and are better for removing finer particles which may have been left by the larger instruments. These are shown in Figure 186. In cases in which the deposit is light, the smaller scalers will often be preferred to the larger instruments. The pull scalers should usually be used first for removing the bulk of the deposit from the lingual surfaces of the lower front teeth. These may be followed by the cleoid or sickle, or both, to remove deposits about the angles or on the proximal surfaces. Oftentimes, heavy deposits on the lingual of the lower incisors, particularly if they extend around the proximal angles, may be removed very nicely by using the pair of push scalers, the blade being applied with its edge part way around the angle into the embrasure. For the molars, both upper and lower, deposits of salivary calculus may be removed from most buccal, lingual and distal surfaces with the pull scalers. The cleoid or sickle may also be used about the distal angles of these teeth. The push scalers will often be more convenient for proximal surfaces, the blade being used through the space from buccal to lingual. This operation involves sufficient practice in the adaptation of the instruments to gain confidence and reasonable skill in management. Both the manner of handling the instrument, and the character of the resistance of the material to be removed, must be learned by actual observation and experience. One* should aim at the first movement, to place tlie edge of the pull instrument between the gum and ihe giugival margin of the calculus, and pull toward the occlusal of the tooth, until force 108 SPECIAL DENTAL PATHOLOGY. enough is applied to break the calculus away. If at one time too much is caught to be broken away witli the use of reasonable force, the position of the instrument should be changed so as to remove a smaller portion at first. In using the push instru- ment, care should be exercised to have a sufficiently good finger rest so that the instrument may be prevented from plunging forward with the sudden breaking away of the deposit and injuring the near-by gum or other soft tissue. In connection with the scaling operation, the dentist or his assistant should frequently flood the mouth with a jet of warm water from a large rubber bulb syringe. This not only keeps the field of operation clear, but is very pleasant and comforting to the inflamed tissues. A water-tank for this especial purpose is shown in Figure 172. This is equipped with an electric ther- mostat (Figures 173, 174 and 175), which keeps the temperature of the water a little above the body temperature. The style of syringe which I prefer is shown in Figure 176. Great care as to wounding the soft tissues will do much to prevent flooding the area with blood. If much inflamed, the gums bleed very freely. In such cases, the bulk of the deposits should be removed at the first sitting, and the patient should be dismissed for a day or two. At the next sitting, the inflammation should be much reduced, and a more thorough operation may be performed. In such cases in which there is much calculus widely scattered among the teeth, the operation is tedious. Both the patient and the operator may tire out. In such a case the operation may be adjourned from time to time until completed. One should not be in a hurry to get through. Following the removal of the deposit, at the same sitting, or at a subsequent sitting, if there is much inflammation of the adjacent soft tissue, the surfaces from which the deposits have ])een removed should be carefully polished with powdered pumice and water, using rubber or wooden disks, or points of various shapes, also orange-wood sticks in the hand. These should all be used with great care not to injure the gingivae. In some positions, and particularly in cases in which the inter- proximal tissue has been more or less destroyed, polishing tapes may be used. It should be remembered that the normal attach- ment of the gingivae on the proximal surfaces of the incisors is very much closer to the incisal edge than on lingual or labial surfaces, and there is danger of cutting away the proximal attachment in the careless use of strips. In any position, strips should be used with the greatest care. Fig. 171. Fig. 171. A sot of six scalers for removing deposits of salivary calculus. This set consists of two pull instruments, two push instruments, a ch'oid form, and a sickle form. If the deposits are slight, the set of instruments sliown in I'^igiin' Isc. will be preferable. *12 Fig. 17-2. Fig. 172. Water tank for di'iitist's office. Tliis tank is kept full of filtered water and the temperature is regulated by an electric thermostat. The faucet to the left is in a pipe leading from the filter. The valve may be adjusted so that the water ilrips slowly. The level in the tank is regulated by the overflow pipe which empties into a waste pipe. Heat is furnished by a 16 c. p. carbon filament lamp attached to the porcelain in the center on top of the tank. The lamp is enclosed in a thin copper well which is fastened to the lid of the tank, so that the well is dry. A little red bull's-eye, just in front of the ])orcelain lamp supjiort, shows when the lamp is on and off. The thermostat projecting from the top of the tank near the left end is described in Figures 173, 174, 175. A thermometer to the right has its bulb in the water. Two rubber bulb syringes fit into " cups " so that the ends of the nozzles are in the water. The tank is not " connected " with the plumbing, and may be lifted off two wall brackets for cleaning. The water is kept at 10,3° in the tank, so that it will be about body tem- perature when the water reaches the mouth. It is very comforting to the soft tissues to flush the mouth frequently during scaling operations, and during cavity prepara- tions as well. The temperature may be kept so close to the body temperature that there will be no pain when washing out the most sensitive cavities. Fig. 174. Figs. 173, 174, 175. Electric thermostat designcfl by the author for bacterio- logical and other dry ovens, and for water tanks, as illustratep('r eixl makes and breaks the current with another point, which is adjustable witli a lluuub- screw. (See Figure 171.) T.y tliis arrangement the lainit burns wlieuever tlie tem- perature drops below thai for which the thermostat is sri ;in.l is turiird otV wlini it rises above. Fig. 1 7(). Tlir larf;o riihhor hull) syringe used for rinsing the ludutli mjhI for irrigation for all purposes in the mouth. Illustration actual size. This syringe holds two ounces. As these arc received from the supply houses, the hole in the end of the nozzle is too small. Enough shouM be cut from the end to give an opening about 1..5 mm. inside measurement. With such a syringe the mouth may be quite thor- oughly cleansed of mucus, blood and debris in scaling operations. In the preparation of cavities it is imi)ortant to have plenty of water to remove most of the mucus. INFLAMMATIONS DUE TO SALIVARY CALCULUS. 109 Caee of tissues by the dentist. During the time of remov- ing calculus, and in the more severe cases for a brief period afterward, the dentist should look after the cleaning of the teeth himself, for it is fair to presume that a patient who has badly inflamed gums from this cause, has not been in the habit of brushing the teeth properly, and could not be expected to do so until after the inflammation shall have subsided. In fact the use of the toothbrush is contraindicated at this time. In addition to the removal of the deposits, the treatment up to the time when the inflammation shall have subsided, should consist of the most thorough mechanical cleansing with the least possible irritation. This may be best accomplished by using warm i^hysiological salt solution in a rubber bulb syringe. This will remove all accumulations of micro-organisms, their prod- ucts and other debris from the surface of the inflamed areas and thus advance the healing process. A half-dozen or more syringefuls of the solution should be forced through the inter- proximal spaces, under and about the gingiva^, giving especial attention to the inflamed areas. The sense of comfort to the patient as a result of several such treatments will often be suffi- cient to induce the patient to become an enthusiastic user of the syringe in the subsequent care of the mouth. The preparation of the salt solution is much simplified by the use of sodium chloride tablets, prepared for the purpose. (See Figure 177.) For reasons which will be fully mentioned later, no anti- septics should be used. It should be recognized that the treat- ment of this condition, with our present knowledge of it, is purely mechanical. Micro-organisms have no influence in caus- ing the deposit of salivary calculus. They do, however, grow luxuriantly in 'these deposits, and have the principal part in causing the inflammation and suppuration of the soft tissues. Careful observations, over long periods of time, involving large numbers of cases, show unmistakably that if harbor points and masses of accumulations are removed at stated intervals, the soft tissues will not be seriously injured. It has been well known for years that we can not sterilize the mouth for even an hour, nor in any way prevent micro-organisms from growing there in case of lesions in the mouth tissues. If we will prevent accumulations of growth of micro-organisms and their products upon the tissues, the phagocytes will be active in attacking any organisms which may have entered the tissues. The chemotac- tic action of antiseptics causes the phagocytes to withdraw; antiseptics are therefore contraindicated. 110 special dental pathology. Cake by the patient. As soon as the inflammation subsides the patient should be trained in doing the necessary cleaning. This is just as impor- tant as the removal of calculus. The dentist should avail him- self of every opportunity to impress this fact. Indeed this is the large part, without which the operation can be of only temporary benefit. There is nothing permanent in the simple removal of calculus. Permanence must depend upon the daily habit of the patient. It must become a part of the patient's care of his or her person. Every one should remember that distinctly. It is the dentist's duty to do this teaching, and in no such case to discharge the patient as well. Do what one will, with our present knowledge of this subject, the tendency will remain for the deposit to recur. We may train certain patients to be so careful in their eating that no deposits will occur and at the same time do much to improve the patient's general health and vigor. That, however, is not fully dependable. It is much easier for patients to control the matter by cleaning than by care in eating, and this is, therefore, the safer treatment. As a matter of fact both should go together. We Imow full well that soft calculus remaining on the teeth only a few hours does no appreciable harm. In many of these cases it is difficult to say at what point the dentist should transfer the care of the case to the patient. In all cases in which there is any marked inflammation of the investing tissues, the case should, as already mentioned, be kept under observation until the inflammation has subsided suffi- ciently to permit the free use of the brush and syringe by the patient. In the majority of cases, even those in which there is much inflammation, the improvement is rapid. Within a few days the patient should usually undertake the cleaning opera- tions. Then the visits to the dentist may be at greater intervals. Some patients will be very willing to do their part, but be very awkward at first, and will need watchful care and instruc- tion. Others will take it up easily from the start. The most difficult thing is to instil the idea of perfect regularity in doing this cleaning. Even with willing patients, it is difficult to accomplish this, although it is absolutely essential to success. As a first step in the training of the patient, the dentist should point out the places where the deposit has occurred and explain how necessary it is that these areas be brushed at least twice daily, if redeposits are to be prevented. The patient should understand that the deposit is soft at first and remains so INFLAMMATIONS DUE TO SALIVAKY CALCULUS. Ill for twelve hours or more, and that during this time it may be easily removed with a brush and plain water. Absolutely noth- ing else is required. Particular emphasis should be laid on the fact that to miss the brushing of these areas a single time may mean that there will be sufficient hardening of a slight amount so that it can not be removed with the brush, also that this slight deposit, by its roughness, serves to attract and hold future deposits. The dentist should see to it that the patient has proper brushes, and a syringe, and he should by using his brush in his own mouth demonstrate the positions and movements neces- sary. He should, in many cases, require patients to bring their brushes to the office, observe their use of them, and instruct them in the proper methods. The use of the rubber bulb syringe by the patient as a part of the daily routine of cleaning the mouth will be appreciated by most patients when they have once learned its use and the sense of comfort which it gives. While deposits of salivary calculus may be prevented with nothing else than the brush and water, the gingivae may be kept in better condition by the use of the syringe and thereby reduce the opportunity for future deposits. A detailed statement of the technic of using tooth-brushes and the syringe will be presented under the heading of Mouth Hygiene. From what has been said, it should be quite obvious that tooth-powders, tooth-pastes and mouth washes are not indi- cated in the treatment of these inflammatory conditions. Subsequent examinations. Every patient for whom deposits have been removed should be impressed with the importance of returning at stated inter- vals for inspection and the correction of errors in cleaning. The frequency of such visits should depend upon the case, and the earnestness of the effort on the part of the patient. In cases in which there has been serious neglect, the patient should be requested to return within a month. If it is then apparent that the cleaning is being well done, a longer period may be given before the next visit. For persons who have become well trained and are in earnest in the care of their mouths, appoint- ments every six months are sufficiently frequent, and for many such people, little or no deposit will be found even then. As will be presented more in detail later, the dentist should 112 SPECIAL DENTAL PATHOLOGY. have a reliable plan of arranging for subsequent examinations. The patient should be informed of the desirability of an exam- ination at a stated time, and the dentist should offer to take the responsil)ility of notifying the patient when the time arrives. This must be done on a plan by which there is practically no danger of failure in the sending of such a notice, for if the dentist assumes the responsibility of notifying the patient, and then fails to do so, the patient will have good cause to blame him. Many patients will welcome such a plan and will be so impressed with the whole scheme of treatment and the interest manifested by the dentist, that they will undertake their part more earnestly. On the occasion of each subsequent examination, the dentist should refer to his previous examination record, and should make a careful inspection of all positions from which deposits were removed to note how successful the patient has been in the cleaning. Whenever a deposit is found, it should be pointed out to the patient, and directions given for the better care required in the future. At the same time a record should be made of whatever deposits are found and the patient should know that this is done. Then the deposit should be removed. Such a plan of recording places of deposit, and checking up the care by the patient at each sitting, together with the educa- tion of the patient as to the nature of the deposit and training in the cleaning necessary to its prevention, all carried out with an enthusiasm and earnestness on the part of the dentist, will not fail to procure the earnest cooperation of most patients. Tliis is especially true if the patient's attention is called to the ahnost certain eventual loss of those teeth which are neglected. For such persons this plan of treatment will not fail. It is dependable. Patients who can not be induced to take at least fair care of their mouths, may as well be advised that their cases are hopeless. Fixation of teeth that have been loosened as a eesult of deposits of salivary calculus. It not infrequently happens that teeth which are loosened as a result of the destruction of a part of their investing tissue by the deposit of salivary calculus will with proper treatment again become tight. If, following the removal of the deposit, the teeth are kept clean, the remaining tissue of the peridental membrane may shrink down and hold the teeth firm Fig. Fig. 177. Bottle eontainiug 100 sodium chloride tablets and an ordinary (Iriiikiug class (illustration actual size) containiuff eight ounces of water. Two salt tablets of IQ^ grains each should be addeiis in uhidi deposits of scnuiial calfiilus occur on llic surfaco ot the ciiiuuel in the siiliuingival space. Deposits in this position are usually flat scales, wiiile those on tiie roots are more lieiierally uoiiular. I'"i(.. isii shows a (lejiosit of serunia! ealciihis iiiider the free <;iiigi\a on tin' laiiial surface of the enamel of a lower incisor tooth. Fig. 181 shows a similar deposit on tiie linouai surface of an upper incisor. Supi)uration of the peridental membrane, resulting from deposits in this position, causes the teeth to move labially. and siudi cases are generally ho])eless, after much pr