M OPERATIVE DENTISTRY. PRACTICAL TREATISE OPEKATIVE DENTISTRY. By J. TAFT, r-ROFESSOR OF OPERATIVE DENTISTRY IN THE OHIO COLLEGE OF DENTAL SURGERY. EIGHTY ILLUSTRATIONS. PHILADELPHIA: LINDSAY & BL A K ISTO X. 18 59. Entered, according to Act of Congress, in the year 1859, BY LINDSAY & BLAKISTOX, In the Clerk's Office of the District Court for the Eastern District of Pennsylvania. C. SHERMAN & SON, PRINTERS, Corner Seventh and Cherry Streets, Philadelphia. PREFACE. The exigences of the Profession seemed to require, for the department of Operative Dentistry, a work that should contain all that is known in this branch of the science. To answer that requirement, the author of the present work has aimed to furnish, in as com- pact a form as possible, the Principles of the Science, properly digested, the Experiments Detailed, the Manipulations Described, and the whole methodized and thus made available to the Student and the Practitioner. In the accomplishment of this object, he has, he believes, included everything meritorious or important in this department of Dental Study. To the dental writers whose labors have lightened, in any degree, the toil of this undertaking, the intelli- gent reader will ascribe the credit due; and to the members of the profession, whose suggestions have found place in various parts of the volume, the author gratefully acknowledges his obligations. J. TAFT. Cincinnati, July 1, 1859. CONTENTS. CHAPTER I. PAGE Introduction, ..... 17 Deposits, ...... 18 Tartar, ...... 18 Origin of, .... 19 Points of Deposit, .... 20 Effects of, .... . 21 Method of Removing, 22 Green Tartar, ..... 24 Origin of, . 25 Treatment of, . 26 Irregularity, ..... 27 Effects of, . 28 Atrophy, ...... 29 Cause of, . 39 Effects of, .... 31 Exostosis, ...... 31 Effects of, .... 33 Cause of, . 33 Denuding, ...... 34 Chemical Abrasion, ..... 36 Cause of, .... 37 Necrosis of the Teeth, ..... 38 Causes of, .... 39 XU CONTENTS. CHAPTER II. PAGE Caries of the Teeth, ....... 41 Causes of Caries, . . . . . . 51 Predisposing causes of Caries, . . . .51 Exciting causes of Caries, .... 55 Comparative liability to Decay, . . . .62 Consequences of Caries, ...... G3 Treatment of Caries, . . . . . .66 CHAPTER III. General Remarks on Filling, . . . . . 71 Materials for Filling, ...... 75 Lead, 79 Tin, 80 Silver, 81 Platinum, ....... 82 Gold, 83 Various Preparations of Gold, . . .85 Crystal Gold, ..... 86 Amalgam, ....... 88 Nonmetallic Materials, . . . . . 91 CHAPTER IV. Instruments for Filling, ...... 94 Heavy Cutting Instruments, .... 94 Drills, ........ 96 Bur Drills, ...... 96 Common Drills, . . . . . .98 Drill Stocks, . . . . . . 100 Broaches, . . . . . . .101 Excavators, . . . . . . . 101 Manufacture of Excavators, . . . .105 Plugging Instruments, ..... 106 CONTENTS. XIII PAGE The File, .111 Use of the File, . . . . . 113 Mode of using the File, . . . . .114 CHAPTER V. Separation of the Teeth, . . . . . 118 CHAPTER VI. Filling of Teeth, ....... 124 Examination, . . . . . . 125 Opening Cavities, . . . . . .126 Removal of Decay, . . . . . . 128 Forming Cavities, ...... 131 Drying Cavities, . . . . . . 139 Introducing the Filling, ..... 142 Block Filling, 148 Forming Blocks, ...... 149 Introducing the Blocks, . . . . 151 Pellets, . . . . . . .154 Adhesive Foil, ...... 154 Crystal Gold, . . . . . . .158 Finishing Fillings, . . . . . . 162 CHAPTER VII. Classification of Decayed Cavities, ..... 166 Filling by Classes and Modifications, . . . 168 First Class, ...... 168 Filling with Foil, ..... 173 Adhesive Foil, ..... 175 Crystal Gold, 177 1st Modification, ..... 177 2d Modification, ..... 179 Second Class, ...... 180 1st Modification, ..... 181 XIV CONTENTS. PAGE Third Class, 183 2d Modification, 186 Fourth Class, . . . . . .187 1st Modification, . . . . . 191 2d Modification, . . . . . .193 3d Modification, . . . . . 194 4th Modification, . . . . .195 Fifth Class, 197 Special Cases, . . . • .199 The Palatal portion of the Crown broken away, leaving the outer portion standing — nerve not exposed, ..... 200 Filling large Cavities on the Labial Surfaces of the Superior Incisor, .... 204 CHAPTER VIII. Pathological Conditions, ..... 20G Treatment of Inflamed Dentine, . . . .210 Tannin, or Tannic Acid, . . . . . 213 Creosote, or Carbolic Acid, ..... 214 Nitrate of Silver, ...... 214 Chlorid of Zinc, . . . . . .216 Terchlorid of Gold, . . . . . 217 Arsenious Acid, ...... 218 Alkaline Caustics, ...... 220 CHAPTER IX. Exposed Pulps, ....... 221 Treatment of Exposed Pulps, .... 223 Destruction of the Pulp, . . . . .231 Actual Cautery, ..... 236 Potential Cautery, ...... 237 Arsenious Acid, ..... 237 Application of, .... 239 CONTENTS. XV Filling Pulp-Cavities and Canals, Preparing the Teeth for Filling, Alveolar Abscess, . Treatment of, PAGE 244 251 259 261 CHAPTER X. Pivot Teeth, Fitting the Crown, Attachment of the Crown, . Metallic Pivots, . 268 272 275 279 CHAPTER XI. Extraction of Teeth, General Remarks, Indications for Extraction, . Extracting Instruments, The Key, Modus Operandi, The Forceps, . Elevators, . Hooks, . The Screw, The Gum-Lancet, Method of Lancing the Gums, Extraction of the Teeth, Superior Incisors, . Superior Cuspids, Superior Bicuspids, Superior Molars, Extraction of Roots, Removal of the Dentes Sapiential, Extraction of the Inferior Incisors, Roots, Inferior Cuspids, . Inferior Bicuspids, 285 285 292 294 295 296 299 311 312 313 315 317 319 319 321 323 326 327 329 331 332 332 334 XVI CONTENTS. PAGE Inferior Molars, ...... 335 Inferior Dentes Sapiential, .... 339 Extraction preparatory to the Insertion of Artificial Den- tures, ...... 340 Conditions to be observed in the Extraction, . . 342 CHAPTER XII. Accidents in the Extraction of Teeth, .' 347 Hemorrhage, ....... 348 Treatment, ...... 350 Fracture of the Alveolus, . . . . .358 Laceration of the Gums, ..... 360 Breaking the Teeth, . . . . . .361 Removal of a Wrong Tooth, .... 362 Dislocation of the Inferior Maxillary, . . . .363 Syncope, ....... 365 CHAPTER XIII. Anesthetics, ........ 368 Ether— Chloroform, ..... 368 Local Anesthesia, ...... 372 Congelation, ...... 373 Extraction by Electro-Magnetism, .... 375 Application, ...... 377 OPERATIVE DENTISTRY. CHAPTER I. INTRODUCTION. As introductory to the following treatise, a cursory consideration of those conditions and diseases of the teeth which demand the aid of dental surgery, would seem appropriate. To refer, however, to all of these, or to remark extendedly upon any of them, would not be consistent with the design of this work, or necessary to a proper understanding of the subjects proposed. Only those affections which pertain to the teeth directly, and which, for the most part, are con- fined to the tooth-substance itself, will here require attention. Nor will the pathology of contiguous parts be introduced ; for the appropriate treatment of these, being mainly therapeutic rather than surgical, would involve a discusssion of questions not within the scope of the present volume. Indeed, it is pro- 18 INTRODUCTION. posed merely to speak of those affections of the teeth, which general^ suggest surgical remedies, and which are implicated more or less in the operations de- scribed in the following pages ; and first, of DEPOSITS. In this term are included those calcareous forma- tions commonly called tartar, a certain coloring mat- ter denominated green stain, and such other impuri- ties on the teeth as result from neglect, the use of tobacco, and like causes. The word TARTAR Implies all calcareous deposits upon the teeth. Of this substance there are several varieties, the more obvious of which have respect to color and consist- ence. In color, there are all shades, from a white as light as that of the tooth, or even lighter, to a jet black ; and in consistence, all degrees, from a thick, gummy mucus, to the density of the dentine itself. The color will, in most cases, be indicative of the density, the lightest shade corresponding with the softest, and the darkest with the hardest consistence. The tenacity to the teeth is also in proportion to the density, the dense and dark adhering most firmly. The density of the deposit, too, is generally indicative TARTAR. 19 of the rapidity of its formation, being in an inverse ratio to this. All the varieties of tartar are composed princi- pally of the same elements, — phosphate of lime, fibrin, fat, and animal matter being contained in them all, though in various proportions. The fact that some varieties are soluble in acids, and others not, has been adduced to prove that they are en- tirely different in their composition. This, however, is accounted for on an other hypothesis : in the softer varieties, the phosphate of lime is so protected by the fat and the animal matter that, under ordinary circumstances, acid can not come in contact with it; but the dense varieties are very soluble, because the acid readily comes in contact with the calcareous portion. Its origin. — It is a precipitate of the saliva, — or at least the phosphate of lime, and probably the fibrin, comes into the mouth with the saliva ; while perhaps the fat and other animal matter are depo- sited from the mucus. In all cases in which this substance is formed upon the teeth, the saliva has a very definite alkaline character, holding in solution the phosphate of lime, which, by the action of the acid mucus upon the saliva, is precipitated. Persons of a lymphatic temperament, or a ten- dency toward it, with muscles of a soft, flabby text- ure, hair light, teeth of a rather inferior quality, 20 INTRODUCTION. and a free flow of saliva, are most subject to the de- position of tartar ; yet there are conditions of almost all constitutions, in which it is freely eliminated. That it is precipitated from the saliva, is a fact so easily demonstrated and so generally admitted, that it need not here be considered. Points of Deposit. — The points at which it is depo- sited in the greatest quantities upon the teeth, are in the vicinity of the orifices of the salivary ducts; and hence it is found most abundant on the inner portions of the inferior anterior teeth, and on the buccal sur- faces of the superior molars. Frequently, also, it collects in considerable quantities upon the external surfaces of the inferior front teeth. The points upon the teeth to which it most readily attaches, are at the necks, immediately beneath the free margin of the gum, and at the termination of the enamel. A nucleus once formed, and it encroaches upon the crown of the tooth, if no means are employed to pre- vent its lodgment, at a rate determined by the con- dition of the saliva. It is deposited first and most abundantly on the necks of the teeth, because here the saliva first comes in contact with these organs, and here remains for the longest periods and in the largest quantities. That it is precipitated very soon after the saliva enters the mouth, is evident from the fact that it is found collected upon the superior molars, just in the TARTAR. 21 vicinity of the orifices of the clucts-of-Wharton, where the saliva cannot he retained for any considerahle time, by reason of the position, but must very soon pass along upon the surfaces of the contiguous teeth, on which we generally find it deposited in much smaller quantities. Indeed, this calcareous deposi- tion has been sometimes found in the salivary ducts themselves. Its Effects. — It exercises no directly injurious influ- ence upon the substance of the teeth ; but it is highly prejudicial to the parts immediately in connection with them, upon which they depend for support. It encroaches upon the gums and alveoli, and causes an absorption of these important surroundings ; and as they become absorbed, its encroachments are accele- rated. In some constitutions this process goes on with little or no annoyance to the patient; while in others, irritation, inflammation, and even suppuration of the gums occur; and thus their destruction is effected in a twofold manner. This irritation and inflamma- tion may extend to the mucous membrane, and in- volve all the adjacent parts. The dental periosteum, also, if susceptible, as in many cases it is, will become implicated in the difficulty; periostitis will ensue, and often suppuration, thus breaking up the attach- ments of the teeth even before the surroundings are removed. The alveolus, too, becomes diseased, and in some instances its death and exfoliation result. 22 INTRODUCTION. Salivary calculus, however, never induces caries of the teeth, nor even favors it. On the contrary, we frequently meet with instances of decay entirely ar- rested by a deposit of tartar in the cavity. Persons of all ages are subject to this affection ; those past middle life being most so, and those advanced in years sometimes having teeth nearly covered with tartar. There are some constitutions whose diathesis is favorable to a deposition of sali- vary calculus through life. Others, again, will be perfectly exempt from it till some peculiar constitu- tional change intervenes, when it will begin to be rapidly eliminated. Method of removing It. — The removal of salivary calculus is an operation that does not involve a great amount of skill, but, with suitable appliances, is easily performed. There are two methods of effect- ing it ; the one, that of scaling and scraping, and the other, that of decomposing the deposit by the appli- cation of an acid. The former is always to be pre- ferred ; for, in the latter, the chemical action of the acid does not stop with a decomposition of the de- posit, but, by the same affinity, attacks the tooth itself. For the successful accomplishment of the operation, instruments of various forms and curves will be necessary, adapted and adjusted to the various shapes and situations of the surfaces to be operated upon. The most common forms are repre- TARTAR. 9?, sen ted in the following figure. The blade of the in- strument should be applied at a slightly obtuse angle with the surface of the tooth, just beyond the edge of Fiff. 1. the deposit next the gum, and thus slid under the tartar, scaling it off to the point, in such a manner as not to roughen up or abrade the enamel. Deposits of this substance on proximal surfaces of the teeth are to be carefully observed, and removed with in- struments of attenuated blades. When the thick incrustations have been thus removed, the surface should then be gently scraped, so as entirely to clean off all remaining portions, and afterward thoroughly polished with fine pumice, or Arkansas- or rotten-stone, and finished by burnishing. During the operation, a frequent employment of the toothbrush with water will be required, to cleanse the mouth of the detached deposits and the increased secretions; and, in general, the completion of the process will occupy more than one sitting. Since this deposit often extends beneath 24 INTRODUCTION. the free margin of the gum, much care is necessary to see that it all be removed. GREEN TARTAR. This deposit has been so referred to by writers, as to convey the impression that it is of the same generic character as salivary calculus. Such a mis- apprehension is hardly pardonable. The teeth of young persons only are subject to this affection, it being often found on those of children three or four years old. It almost always appears on the labial surfaces of the superior front teeth, and in largest quantity near the margin of the gum. It is seldom seen on the inferior teeth, and only on the anterior surfaces of the superior. The color of this deposit is very dark, inclining to green. Wherever it attaches, the surfaces of the teeth are abraded, and when it is of long standing, the entire enamel beneath it is destroyed, and the dentine is gradually involved in the dissolution. This effect upon the teeth is not produced by the coloring matter observed upon them, but by an acid in combination with this material before it is deposited. The stain is a precipitate from this compound, and the acid, leaving this, com- bines with the calcareous ingredients of the teeth, to their detriment as above; but the precipitate is entirely innocent. GREEN TARTAR. 25 Its Origin. — Green tartar, or green stain, doubtless lias its origin in the mucus, when this is in a particular acid condition. That it does not proceed from the saliva is proved by the fact that it is never found where there is a free flow of saliva, or where this has free access; but the point of its deposit is where the saliva is least frequently present, being most abun- dant in cases in which there is a large relative amount of mucus, and this in a very acid condition. But the query might arise here, if the mucus of the mouth were wholly in that condition, why would not the teeth suffer from it elsewhere. Because, on the masticating surfaces of the teeth, the friction of the food will prevent it, and on the inner surfaces, the friction of the ton sue ; besides, wherever there is a free flow of saliva, this will have a counteracting effect. Decay goes on very rapidly, after it has once commenced, upon teeth affected by this deposit. There are points of dissimilarity between this green tartar or stain and salivary calculus, that it may be well to notice. The latter is from the saliva ; the former from the mucus ; and hence the one exists where there is an abundant flow of saliva, and the other where the relative quantity of this is small. The calculus is deposited when the saliva is in an alkaline condition ; the stain, when the mucus is very acid. The former is deposited in large quanti- ties and thick incrustations, and upon the surfaces of 26 INTRODUCTION. the teeth, and is easily removed without detriment to their substance ; whereas the latter is a thin film, barely sufficient to stain the surface, and yet it enters into the tooth-substance itself, and cannot be removed without detaching some portion of the tooth with it. The one seems rather preventive of caries, which does not occur beneath it ; but the other is highly promotive of decay. With these marked features of difference, it is surprising that the two should ever have been confounded, since it is so important that the distinctive character of each be understood, in order to its correct treatment. Treatment. — In order to a perfect and final remedy for green stain, therapeutic treatment must be com- bined with the operative ; but only the latter will be here described, which has for its object the removal of the deposit, and the rendering of the eroded sur- face smooth and polished. There are two or three methods of accomplishing this object. When the erosion is but slight, it will be effected with pul- verized pumice or Arkansas-stone, applied with water till the stain disappears, and with the subsequent use of the burnisher with a solution of soap. But when the erosion is too extensive to be thus reduced, it must be cut down with a file, and then finished with stone and burnisher, as before. And when the ero- sion is extreme, a cutting-instrument must precede the file. IRREGULARITY. 27 IRREGULARITY. By this term we imply those variations from a beautiful and natural position, in which the teeth are so frequently found. The principal cause of irregu- larity is a disproportion between the actual size of the arch, and the size required for the accommoda- tion of the teeth. When this disproportion exists, the teeth which are first irrupted, occupy very nearly their proper position ; but those which come in after- ward, are more or less disarranged, in proportion to the preoccupation of the space. There are cases in which the roots of the temporary teeth are not ab- sorbed, and the permanent teeth are irrupted out of their true position, even when there is room enough for them were the former removed. Irregularity is mainly confined to the front teeth, and consists in either an inward or an outward inclination, and, in some instances, both. Sometimes the incisors are turned round in the socket, so that the edge stands at a very considerable angle with the proper position. The upper teeth are oftener materially disarranged than the lower, though the latter frequently exhibit some irregularity in front, in consequence of a crowded condition. The teeth most liable to be out of position are the cuspidate. These, of the teeth of replacement, are the last in their irruption ; and it often occurs that the arch is previously wellnigh oc- 28 INTRODUCTION. cupied ; in which case they are thrown outward. When there is any irregularity of the bicuspids, it is that of an inward inclination. The first and second molars are very seldom out of proper position. The third molars, however, for w r ant of room, are some- times thrown out toward the cheek, or even pre- vented from coming out at all in any direction. Effects. — In all cases, irregularity is favorable to decay. It is even maintained by some that the organic structure of irregular teeth is less perfect than that of regular, because the former are impeded in their irruption, and thus impaired. But this, to say the least, is questionable ; for it will be remem- bered that the crowns of the teeth are formed and completely ossified before they can be affected by a crowded state ; and it is hardly probable that they could be materially modified in their structure after this period. The crowns of the teeth are never de- formed by a crowded condition. The principal cause of the liability of irregular teeth to decay, is the fa- cility they furnish for the lodgment of foreign sub- stances about them, and the difficulty they present to its removal. And again, in irregular teeth, parts are approximated that nature did not intend should be brought together. Irregularity impairs the speech, impedes the mastication, and often distorts the coun- tenance and deforms the features. ATROPHY. 29 ATROPHY, This affection is characterized by defective spots in the enamel, white, chalklike — which scarcely ever penetrate the dentine. In these spots there is nothing of that organic structure exhibited by well formed enamel. They are in all cases quite small, but vary greatly in number. They are often found arranged in transverse rows across the tooth affected. The superior incisors are most frequently found with atrophy, though the bicuspids and molars sometimes exhibit it. The front upper teeth are attacked by it only on the anterior surfaces. Instead of the spots, we sometimes find pits, or indentations, into or through the enamel, which occa- sionally run together, so as ultimately to form trans- verse grooves of considerable extent upon the teeth. In many cases, where on the irruption of the teeth the spots only are presented, the organs are not injured, except in appearance, the spots retaining the smooth, enamellike surface during life. In other cases, the spot is of such a soft, friable texture, that it early crumbles out, leaving the little pits above referred to. These indentations, however, sometimes exist at the first appearance of the tooth, but more frequently afterward, being formed by the crumbling- away of the defective portion. Atrophy usually occurs on teeth of good structure, 30 INTRODUCTION. short, thick crowns, and rather yellowish color. The long, thin, white tooth, of imperfect organization and insufficient density, seldom or never presents an atro- phied condition. The Cause. — It may be difficult to point out the precise cause of this affection, but some facts in re- gard to it are very obvious. There is, in every case, an obstruction in the development of the enamel at the point of defect, and at the time of its origination. In some cases, doubtless, there are a deficient amount and an inferior quality of the material elaborated for the upbuilding of the structure; and this is probably the case when the pits exist at the irruption of the teeth. In other instances, the requisite quantity of material may be elaborated, and yet the vital energy be insufficient to organize it, as in the case of the spots referred to. The latter condition is more fre- quent than the former, as is evidenced by the more frequent appearance of the spots than of the pits. We are led to infer, then, that the origin of this affection is for the most part constitutional, and not local. There are commonly found traces of it on all the teeth whose enamel was in process of formation at the time of the interruption. Any general disturbance, such as to interrupt the assimilative process, would be detrimental to the per- fect formation of the tooth. Again, some affections may materially affect the organizing power of the EXOSTOSIS. 31 system, without interfering with the assimilative power. Any disease that should interrupt the func- tions of the digestive apparatus, would be prejudicial to the process of assimilation ; whilst other diseases, such, for instance, as those of a febrile character, would diminish the vital power, and consequently the ability to build up organic structures, without interrupting in any special manner the process of assimilation. These things are referred to here for the purpose of showing under what circumstances atrophy of the teeth may occur. Effects. — In the best formed teeth, there are no unpleasant results from atrophy, other than its de- traction from their beauty. The spots are unsightly, and when the pits are present, they become dark, and sometimes black, from deposit ; which, by ordi- nary means, is difficult of removal. In teeth of infe- rior structure, decay often supervenes in these pits, and, extending thence, involves the other parts ; and anything that will affect the tooth-substance, will affect the spots in a greater degree. EXOSTOSIS. This term, critically denned, implies outgrowth from a bone; but, as applied to the bones generally, and particularly to the teeth, it probably conveys the idea of groicth upon a bone. The affection thus clenomi- 32 INTRODUCTION. nated is common to all the bones ; some, however, being more frequently attacked by it than others. It occurs upon the roots of the teeth, but is never developed where there is no periosteum. The man- ner of its deposit is not uniform ; but it is commonly in an enlargement on the point of the root, or from the point some distance toward, and occasionally all the way to, the neck of the tooth. In some cases, it extends entirely round the root, and in others, is con- fined to one side. It sometimes results in such an enlargement of the root, especially if it is near the point, as to render the tooth very difficult of removal. When it is bulb-form, the entire attachment of the tooth may be broken up, so as to allow this to rotate in the socket, and yet the tooth be very difficult to remove ; indeed, in some instances, impossible, with- out cutting away a portion of the process. The density of the deposit is usually greater than that of the root on which it is found ; though in this respect there is considerable variation : in a few in- stances w r e have found it softer than the root proper. The surrounding parts are absorbed for its accommo- dation. The color of the substance is slightly yellow, not differing much from that of the root itself; and frequently it exhibits a seinitranslucent appearance. The rate of its formation varies considerably, some- times increasing so rapidly as to occasion much diffi- culty, and at other times seeming to advance very EXOSTOSIS. 33 slowly ; and frequently it is arrested altogether. Roots are often found affected with exostosis, that have been dead and crownless for a number of years, and yet have never, so far as known, given any trouble because of the affection ; and teeth perfectly healthy in other respects may be thus affected. Its Effects. — It always increases the difficulty of re- moving the tooth, either by enlargement of the point of the fang, or by deposit upon one side of it, causing it to curve ; in which latter case the difficulty is all the greater, from the impossibility of determining the direction of the curve. It sometimes produces a dis- eased condition of the surrounding parts — in some in- stances chronic inflammation — that will continue as long as the tooth remains. Nervous affections often result from exostosis, either through irritation caused by pressure on the nerve, or through the diseased condition of the surrounding parts. The floor of the antrum is sometimes absorbed away, in consequence of the enlargement of the point of the fang; and •then disease of the lining membrane of that cavity generally ensues. The Cause. — The cause of this affection is not well understood. It is most probably deposited by the periosteum when this is in an abnormal condition ; but what peculiar condition, it is not clearly ascertained, though some have supposed it to be inflammation. It is patent, however, that something more than a 34 INTRODUCTION. state of simple inflammation exists ; for there is in- flammation in numerous instances without this de- posit. Again, in all cases where there is periostitis, that state is definitely indicated by percussion upon the affected tooth ; indeed, in the occlusion of the jaws, pain is usually experienced. Yet there are found many teeth whose roots are subjects of this deposit, that have never given any indications, either by pain or otherwise, of a diseased condition. This subject is one in which there is room, at least so far as dentists are concerned, for extensive obser- vation. DENUDING. This consists in a wasting-away of the enamel of the anterior teeth, from the points toward the necks. The affection, however, is of too rare occurrence to demand extended consideration. The color of the enamel is not changed by this process, nor is its natural polish impaired by any abrasion. The den- tine, on becoming exposed by this removal of its natural protection or covering, is perfectly smooth, but of a yellowish cast, in some cases inclining to brown. When the enamel is removed, there seems to be a cessation of the destructive process ; for the crowns of such teeth will, in many instances, endure DENUDING. 35 for a long time — indeed, till they are worn down by the friction in mastication. This wasting process usually begins at the points of the teeth, and proceeds toward the necks, on all sides, till the enamel is entirely destroyed. Some- times, however, it commences on their labial sur- faces ; this is particularly the case with the superior anterior, but very seldom with the inferior teeth. The affection, however, attacks the inferior more fre- quently than the superior teeth ; yet it is often found assailing both with about equal energy. The cause of the disease is not well understood, though it is generally conceded to be the operation of an acid contained in the mucus. Doubtless, the agent producing the affection is contained in the mucus ; for it usually occurs where there is a large relative amount of this secretion ; but that it is an agent of a very decided acid character, we are not prepared to affirm. Decay of the teeth does not seem to progress with greater rapidity while this affection exists, than at other times; and again, the enamel does not present the roughened, abraded appearance we find resulting from the operation of any ordinary agent. With these apparently incongruous facts, it is rather difficult to arrive at a definite conclusion as to the precise manner in which this condition is pro- duced, or the exact character of the agent instru- mental in its production. 36 INTRODUCTION. CHEMICAL ABRASION. This consists in a gradual destruction of the entire substance of the crown of the tooth — the enamel and the dentine. It is an affection of comparatively rare occurrence. It assails the superior more often than the inferior teeth, though both are subject to it. It begins upon the points of the central incisors, wast- ing them away most rapidly at the median line, from which it progresses each way, involving the lateral incisors, cuspids, and sometimes the bicuspids, so that a curved line is presented by the edges of the teeth, of greater or less inclination, according to the rapidity of the process. When the superior teeth only are affected, the opening between the ends of the upper and of the lower front teeth, when closed, is a semi- ellipsis. If the inferior teeth are affected, as is some- times the case, then the opening will be an ellipsis. In the case of Mr. G., the affection had been in process about two years and a half; the wasting- away extended to the first bicuspids both above and below; and when the jaws were closed, the ends of the upper and of the lower central teeth were about one third of an inch asunder, and the opening was of the elliptical form. It was a mystery to him. Tw t o years and a half before, his anterior teeth shut close together on the ends. He had not used them in the mastication of his food, for his molar teeth were all CHEMICAL ABRASION. 37 good, and sufficient for this purpose ; and moreover it had been impossible for him to use them in mastica- tion, since he could not bring them together ; and he had not been in the habit of putting any hard sub- stance between them. The Cause. — The cause of this affection, like that of denuding, is not well understood. It is supposed, however, to be induced by an acid contained in the mucus. If this supposition is correct, it must be some acid with whose nature we are but little, if at all, acquainted ; or, if any ordinary acid, it certainly must be modified by very peculiar circumstances. The surface upon which it acts is always perfectly smooth and polished, never presenting that rough- ened and abraded appearance caused by the action of any ordinary acid upon enamel or dentine. And again, if this affection results from the operation of an acid in the mucus, why does not this acid, to some extent at least, affect the teeth at other points ? Such is not the fact; and caries that has previously commenced at other points on the teeth, does not progress more rapidly during the existence of this disease, than before ; but it certainly would, if there were a large quantity of acid in the mucus. It has been supposed that the mucous follicles of that part of the tongue which comes in contact with the teeth at the affected part, are the agents that produce the disease. Of this, however, there is not 38 INTRODUCTION. evidence sufficient to warrant an adoption ot the theory. The cupping of the molars and cuspids bears strong indications of being an analogous pro- cess, and yet no such influence can exist for its ac- complishment. We have no theory on this subject to present, regarding it as still an open field for in- vestigation. There can be little doubt, however, that the cause of denuding, of chemical abrasion, and of cupping, has its origin in the constitution, is not merely local, and may be removed, and the affection arrested, by constitutional treatment. NECROSIS OF THE TEETH. By this term is understood the death of the part affected. It has been remarked that the condition is similar to mortification in the soft parts of the sys- tem. But in the latter there occurs a change of structure ; whereas, in the bones, and particularly in the teeth, there is not necessarily any change conse- quent on the loss of vitality. The teeth have their organic connection with the surrounding parts by the external and the internal periosteum and the pulp ; their crowns depend for vitality upon the internal organism ; and when this is destroyed, they are wholly necrosed, or deprived of vitality, as is evident from the total loss of sensibility in them immediately after the destruction of the pulp. NECROSIS OF THE TEETH. 39 Necrosis of the teeth differs from that of the other bones in some particulars, one of the most obvious of which is, that in the former there is no exfoliation, the living structure not having the power to throw off the dead or necrosed portion. Again, a dead part in contact with the living, does not materially affect it. The roots of the teeth depending for their vi- tality upon both their internal and their external connections, the former of these connections may be destroyed, without materially affecting the latter. Thus, a tooth may be partially necrosed, — that is, vital in one part and dead in another, — without im- mediate injury to the living portion, and without separation of the living from the dead. It is a happy provision that the analogy between the teeth and the other bones does not, in this respect, obtain ; for if it did, we should find the crowns of the teeth exfo- liated from the roots in all cases, immediately after the death of the pulp. There results but little change of color to the teeth from necrosis, unless coloring matter is absorbed by the dentine from the decomposed pulp; though of course the lifelike lustre and appearance of the living teeth are not present. Total necrosis destroys the entire organic connection of the teeth with the surrounding parts; in which case they are imme- diately expelled from their sockets as useless. Causes. — Caries is a very common cause of ne- 40 INTRODUCTION. crosis, especially the partial form of it to which reference is made above. Protracted fever, or dis- eases of any kind that diminish the vitality of the constitution, will in a corresponding degree diminish that of the teeth, and sometimes destroy it entirely. Excessive medication, especially with mercurials, will sometimes produce partial, and occasionally total ne- crosis, as will also sometimes blows or violent shocks, when these are not sufficient to displace the teeth. Great and sudden changes of temperature have been reckoned causes of this affection ; but it may well be doubted whether they are adequate, without the con- currence of other influences. CHAPTER II. CARIES OF THE TEETH. Notwithstanding the teeth are so important in the human economy, having functions so various and so extensive to perform, they are greatly neglected in most instances, and, in many subjected to positive violence ; as, for example, in crushing or biting hard substances, sustaining weights, and suffering severe percussion, sudden extremes of temperature, bungling- dental operations, etc. • Very few give that attention to these organs, which is requisite to preserve them from injurious influences ; and, owing to artificial modes of life, and consequent impairment of health, this is often difficult to do. Indeed, these influences are frequently not known, and the causes of disease in the teeth not explored. Such is the truth, to some extent, in regard to caries ; though this affection is more generally a re- sult of conditions well understood. The dentine is affected more frequently by caries than by any other form of disease. It is both frequent in occurrence and fatal in tendency. Scarcely any that have at- 42 CARIES OF THE TEETH. tained maturity, are exempt from its ravages. It is a disease which the resisting forces can but feebly withstand, and in which the recuperative powers are of no avail. Some maintain that softened dentine does in 'many cases regain its normal density; but this cannot be, unless it retains its vitality. But any agent possessed of sufficient energy to decompose the dentine, will destroy its vitality. What is that decomposition ? Either a lack of vital power to maintain the integrity of the organic structure, or the action of some agent having an affinity for a cer- tain part of the dentine more potent than that vital power. In either case, the vitality is destroyed. In an organized structure, removal of one of its compo- nent parts occasions a loss of vitality in the rest. Caries makes its first attack upon the dentine, and progresses most rapidly in the direction of the tubuli. There are variations from this course ; as, for exam- ple, in the large superficial caries on the labial sur- faces of the superior incisors. In many cases, too, it advances immediately beneath the enamel. Portions of the dentine imperfectly protected by the enamel, on account either of an injured condition or of an im- perfect formation of the latter, are liable to be at- tacked by this disease ; and points that, by their location or any other unfavorable circumstance, re- tain injurious agents in contact with the tooth, are very subject to decay. CARIES OF THE TEETH. 43 The attack and progress of caries are modified by the constitution of the teeth. These may be defec- tive cither originally or accidentally. Original de- fectiveness would extend to all the teeth of the same individual, whilst accidental might exist only as to some of the teeth in the same mouth, and these only at particular points. Such conditions are peculiarly favorable for the attack of caries. When the whole crown of the tooth is imperfectly organized, the decay will advance with uniform rapidity, till the whole is destroyed. But when it is only portions of the tooth, the caries, after a time, becomes retarded in its prog- ress, and in some cases checked altogether. Among the circumstances which modify the prog- ress of this disease, are, a change of the condition or character of the agencies producing it, and an increase or a diminution of the amount of such agen- cies. The progress of caries will also be governed somewhat by the age of the person whose teeth it attacks, and by the peculiar constitution of the organs themselves; for, in regard to constitution, these present an almost infinite variety, the relative proportions of their constituents being exceedingly various, even in persons of the same age, and con- tinually varying in the same person at different ages. There is a constant change going on, the calcareous elements increasing, and the animal decreasing. But a proper relative amount of elements may be elabo- 44 CARIES OF THE TEETH. rated, and yet a defective organization exist. This condition arises from inipotency of the organizing power, or from a failure of the materials to arrange and combine ; and it is dependent entirely on acci- dental causes. In vital energy, indeed, the teeth exhibit great diversity ; and this corresponds with, and to some extent depends upon, the vital energy of the general constitution. Dead dentine is decom- posed more readily than living ; and hence the con- clusion that vitality resists caries, and that this re- sistance corresponds with the vigor of the vitality. The points most frequently attacked by caries, are the proximal surfaces of the teeth, the indentations and fissures on the masticating surfaces of the molars and bicuspids, the longitudinal depressions on the buccal and palatal walls of the molars, and the necks of the teeth at the termination of the enamel. On the proximal surfaces, the enamel is thinner than elsewhere ; and the situation is pecu- liarly favorable for the accumulation and retention of injurious agencies. The union of the enamel in the fissures and indentations of the crowns of the molars, is often imperfect ; and thus there is a way of entrance for vitiated fluids to the dentine. Decay is found at the terminations or intersections of these fissures earlier than at any intermediate points. The indentations, or grooves, on the sides of the teeth, are usually attacked by caries at that point next to the CARIES OF THE TEETH. 45 neck. Less frequently, the disorder is exhibited at the neck, just beneath the border of the enamel, under which it burrows with a transverse extension. The order in which the elements are removed, is governed by the nature of the agency which effects the decomposition ; and this is usually one having an affinity for the calcareous elements strong enough to destroy the texture of the dentine, and remove the earthy portion. Those acids which have an affinity for the lime of the dentine, produce its decomposition in this manner. When the decay is thus caused, the portion remaining in the cavity is soft, and approximates the gelatinous condition as the cal- careous material is abstracted. Agents of a different character, too, often produce decay. Alkalies will act upon the animal portion of the dentine, and remove it ; and in caries thus produced, the residue is friable and chalklike. In other cases the constituents are simultaneously removed. Nitric acid will cause an entire breaking-up of both the earthy and the animal constituents. Death of the dentine generally induces decay, decomposition being more easy after the vitality is lost. But there are exceptions to this. The dentine outside of the decay may be in an in- flamed and irritable condition, so that contact with the decayed portion will produce pain ; and thus we may be led falsely to conclude that the softened den- tine is sensitive; and, indeed, it is maintained that 46 CARIES OF THE TEETH. in some cases the partially decomposed dentine is so, on the supposition that a small portion of the calca- reous elements may be removed, and yet the fila- ments of the nerve ramifying the part, not be de- stroyed. The progress of caries is far more rapid in the crowns of the teeth than in the roots, for the reason that the former are more exposed to the influences of external injuries. It is true that the crowns are covered by enamel, which is designed to shield the dentine from injury, but which is often defective, and on which are accumulated agencies that it cannot re- sist, even when it is perfect ; so that the enamel itself is sometimes decomposed. The roots, too, possess a higher degree of vitality than the crowns, and their ability to resist the encroachments of decay is cor- respondingly greater; and hence we often find the roots of teeth solid and free from decay, the crowns of which have been removed by rapid decomposition. Injurious substances are sometimes pressed into con- tact with the dentine, through defects in the enamel, or under its projections, and there retained till their mischievous effect is produced. It is maintained by some writers that caries is con- tagious. Dr. Koecker was of this opinion. The question, then, is, whether there is any property in the decayed dentine of one tooth, capable of producing the same condition in the healthy dentine of an other. CARIES OF THE TEETH. 47 The residue of abnormal dentine in the soft decay, consists of the animal elements and a small portion of earthy material ; and in decay in which the gela- tinous constituent is abstracted, the remainder is chalklike, consisting mainly of phosphate of lime. In neither of these is there anything that can possi- bly operate on the healthy dentine. There is one thing here, however, that is worthy of remark, and that lias perhaps led to the mistaken notion that caries is contagious : decayed dentine will absorb and retain fluids that injuriously affect sound dentine; and when the decay is on the proximal portion, two teeth are subject to the same exciting cause. But it is seldom that two teeth thus situated are both in the same stage of decay; a fact principally attributa- ble to the difference in their constitution. The decay of the teeth in pairs has also been adduced as evi- dence of the contagious character of the disease. This, however, results from the fact that the pairs are formed at the same time ; are subject to the same influences in their formation, and hence are constituted alike ; and if one of the pair is defective, the other will be in a like condition. When there is a vitiation of the saliva or mucus, they will be simi- larly affected. In no common acceptation of the term contagious, can it be applied to caries of the teeth. The color of caries is exceedingly various, from 48 CARIES OF THE TEETH. that of healthy dentine, through every intermediate shade, to jet black. The rate of the progress is indi- cated by the color of the decay, being slower as this is darker, so that when the decay becomes almost stationary, the affected portion is black. The degrees of color are differently enumerated by different writers; as, by Koecker five, by others seven, and so on. Three, however, are sufficient for our pur- pose : white, brown, and black. The sensitiveness of the dentine is greatest in teeth affected by the white decay, and usually decreases as the color darkens ; though there are exceptions to this rule ; for occa- sionally we find teeth affected by dark decay, that are quite sensitive. The light-colored decay is more difficult to arrest than the dark. In many cases of the former, filling seems hardly to retard its pro- gress; whereas, in the latter, by proper filling, the advance of the decay may be checked altogether. The cause of the dark color of caries is not perfectly comprehended. It is doubtless a deposit upon the decayed part, and is most probably a metallic oxyd, as iron, sodium, potassium, and calcium are found in the saliva and mucus in several combinations. The opinion is entertained by some, that this deposit protects the dentine from the influence of injurious agents. But this is most probably not cor- rect, at least to any perceivable extent. If the deposit does thus serve as a protection, the removal CARIES OF THE TEETH. 49 of the discolored portion would subject the dentine to a renewed attack of caries, which experience assures us it does not do, but that after some time it assumes the dark hue again. Those who maintain this opinion, refer, in support of it, to the fact that a deposit of oxyd of silver being made upon a decay of light color, by the use of nitrate of silver, the prog- ress of the decay is thereby retarded. This retardal, however, is effected more probably by a change in the character of the decay, than by any protection afforded by the coating of oxyd of silver. Some sensitiveness commonly accompanies caries. It does not often amount to pain, but is rather a sense of uneasiness ; yet, when anything is brought in contact with the sensitive dentine, as sudden changes of temperature, acids, etc., intense pain may be produced. Dr. Koecker remarks that caries is most tender in its first stages ; and Dr. Cone, that when a tooth is attacked by it, the sensitiveness is increased. The surface of the dentine, or that part united to the enamel, is susceptible of the most acute sensitiveness, since here is the place of termination of the nerve-fibrils which ramify the dentine, and which, whether in a healthy or a diseased state, are more sensitive at their terminations than along their extent. "When there is inflammation of the dentine, intense pain may be produced by the contact of an instrument, in a cavity of decay, at the line of union D 50 CARIES OF THE TEETH. of the dentine with the enamel, and very little sensi- tiveness be present elsewhere in the cavity. Sensi- tiveness of a uniform character sometimes pervades all parts of the cavity, while at other times it may be very intense at one point, and very slight or entirely absent at any other. A thin lamina of the dentine lining the whole cavity, may be uniformly sensitive, and in some cases this sensitiveness may involve the entire body of the dentine. By means of this sensitiveness, warning is trans- mitted to the pulp, which emits osseous material with increased energy ; and thus a process of filling up the natural cavity of the tooth is instituted, that the decay may not encroach upon the nerve. But this warning may, in some degree, be transmitted to the pulp, though there be no increase of sensitiveness. This sensitiveness is modified by the character of the teeth, the nature of the decay, and the state of the patient's constitution. The teeth of the same person will be more sensitive at one time than at another, because of a greater irritability of the ner- vous system. Those teeth which decay most rapidly, are usually most sensitive; though in teeth whose vitality is lost considerably in advance of their decay, there is no sensitiveness at all. Except in such cases as last mentioned, the whitest and most rapid decay has most sensitiveness, the brown much less, and the black scarcely any. CAUSES OF CARIES. 51 CAUSES OF CARIES. The causes of caries of the teeth may be considered under two general divisions — predisposing and ex- citing. Of the former, some are original, others acci- dental. The original development of the constitu- tion may be defective, either from original or from accidental defect in the parent; but more certainly from the former. Constitutional characteristics are transmissible, and a defect is as surely hereditary as anything else. In the fetus, during gestation, there may have originated germs from which perfect organs can never be developed, and these germs may be more or less defective according to the constitutional condition of the mother, or according to accidental conditions to which she may be subject, and which may seriously affect the fetus. After birth, too, the child is exposed to injurious impressions, which will, to a greater or less degree, render the development defective; as imperfect nourishment and the diseases and functional derangements peculiar to childhood. A diseased condition, or functional derangement, will interrupt the proper elimination and perfect upbuild- ing of the materials necessary for the perfect struct- ure ; and indeed anything that will disturb the equilibrium of action in the system, may be detri- mental to the teeth. In some instances the teeth will exhibit the pecu- 52 CARIES OF THE TEETH. liarities of the mother, and in others, those of the father ; while sometimes they participate those of both parents ; and when the parental imprint is thus found stamped on the teeth, it will also be found that those of the same class decay at the same point and at about the same age as in the ancestor. In such cases the defect is manifestly hereditary ; it cannot be accidental : the coincidences thus constantly oc- curring preclude any other conclusion. Hereditary taint, then, may be regarded as a predisposing cause of caries. Impaired vitality is another predisposing cause ; and not only impaired vitality of the teeth and con- tiguous parts, but also that of the general system. Indeed, the vital vigor of the teeth depends upon that of the general system, and, when there is no local influence at work, corresponds with it ; so that when the general system is in the most healthy con- dition, the teeth possess the greatest power of resist- ance to deleterious agencies. This resisting power is, at best, comparatively feeble ; but its feebleness is, to some extent, compensated by the peculiar structure of the teeth, which is less liable to decomposition than any other part of the human body. Yet the integrity of these organs depends much on the main- tenance of a healthy vitality, and this on that of the general system. A dead tooth will decay far more rapidly than a living one in similar circumstances ; CAUSES OF CARIES. 53 and hence the conclusion that vitality resists inju- rious agents, and that the resistance will be propor- tionate to the vitality. All febrile conditions promote and facilitate decay, and frequently in two ways : by diminishing the general vitality, and by changing the secretions of the mouth so that these act injuriously upon the teeth. Accompanying such conditions, there is gene- rally inflammation of the dentine ; and in such cases, this always partakes of the general disorder so as to become very susceptible to injury. All diseases, indeed, that impair the vitality and change the secre- tions, may be considered predisposing causes of decay, and some even more; dyspepsia, for instance, being not only predisposing, but also exciting, since it pre- pares in the stomach an acid that is almost continu- ally thrown upon the teeth, and that acts upon them with great energy. Residence in miasmatic regions, is also a predisposing cause, inducing unfavorable conditions. Diminished vitality may result either from consti- tutional or from local causes. These latter are such as produce an irritable or diseased condition of the immediate parts, or an abnormal condition of the dentine, without the power to effect its decomposi- tion. Local causes of a diminution of vitality are not in their character so formidable, and not so diffi- cult to control, as those which are constitutional. 54 CARIES OF THE TEETH. Many medicinal agents are regarded as predis- posing causes of caries ; and among these, mercurials occupy a prominent place. They operate by vitiating the secretions of the mouth, and producing an abnor- mal condition of the periosteum about the fangs of teeth, the mucous follicles, and the salivary glands. Some entertain the opinion that the abnormal action of the absorbents, induced by mercurials, predisposes to decay. Dental operations performed at an improper time and in an improper manner, may be reckoned among the predisposing causes of caries. The vitality of the teeth may be thus impaired, or a diseased condition established, or the part operated upon may be per- mitted to remain rough, so that foreign substances will be retained, and, becoming vitiated, produce a deleterious effect. Often, from an improper use of the file, extensive inflammation of the dentine super- venes, which is sometimes followed by death of the tooth, and by disease of the contiguous parts. Arti- ficial substitutes imperfectly adapted, are, in many instances, the occasion of caries; not that clasps or the edges of the plate tend directly to injure the tooth, but the agencies superinduced by them do, and especially when the material used is not of the right quality. Lack of proper exercise in mastication induces a condition that is favorable to decay. It does so, EXCITING CAUSES OF CARIES. 55 however, rather by favoring injurious agents to act on the teeth, than by imparting any direct predispo- sition to the teeth themselves. Substances of all kinds are deposited much more rapidly when the teeth are idle. The teeth cannot, with impunity, undergo sudden transitions from one extreme of temperature to another, or even such extremes as may be endured by the surrounding parts. By these, inflammation of the dentine may be induced, and the vitality of the teeth diminished, so that, even in friable teeth, checking of the enamel will occur, and thus a condi- tion arise that will facilitate decay. EXCITING CAUSES OF CARIES. When there is a predisposition to caries, any of the exciting causes act with more vigor. Teeth that are well constituted, and that have retained unimpaired health and vitality, withstand influences that, in less favorable circumstances, destroy them in a very short time. The immediate cause of decay is the action of agents chemically upon the teeth. It is not here proposed to enter upon an investigation of the man- ner in which these various agents operate ; for that would open up a vast field for exploration — a field outside of the province of this work. The sources of these agents, however, are several : as, vitiated secre- 56 CARIES OF THE TEETH. tions of the mouth, the saliva, and the mucus; abnor- mal secretion from the stomach ; decomposition of animal and vegetable substances in the mouth ; acids taken with food, or administered as medicines; and galvanic action. Sometimes the secretions of the mouth are wholly acid, and thus these natural products, so vitiated, be- come instruments of mischief. The natural state of the mucus is acid, but that of the saliva alkaline ; so that these secretions counteract each other; but when the saliva and the mucus are both acid, the teeth must suffer. These secretions may become vitiated, through inability of the glands, from disease or an enfeebled condition, perfectly to perform their functions ; or the blood may be in an abnormal state, and the glands unable, on that account, though they were healthy, as they seldom are in such case, to elaborate healthy saliva: when the fountain is cor- rupt, the stream cannot be pure. Thus, anything that produces a diseased condition of the blood, tends to the decay of the teeth ; and such diseased condi- tion often has a direct injurious effect on the secre- tive apparatus, and so works a double harm. But to the theory of the pernicious influence of the saliva, it may be objected, that, if it were true, all parts of the teeth would be alike affected. This objection, however, will lose its force when it is con- sidered that the teeth, in many cases, are not equally EXCITING CAUSES OF CARIES. 57 well organized in all their parts ; that some parts are not so well protected as others ; and that between the teeth there is room for the retention of saliva and foreign substances, which there combine their influ- ence upon them. In cases in which there is a great quantity of viscid saliva constantly flowing, the teeth decay very rapidly. The decay is of a light color ; so light, indeed, that, in many instances, it is difficult to distinguish it, by this, from undecomposecl dentine. The gastric fluid often becomes deranged by irrita- tion or disease of the stomach, so that the function of the latter is very imperfectly performed, and fer- mentation of the food occurs, evolving agents that injuriously affect the teeth. In dyspepsia, such agents are often brought in contact with the teeth by eructation and vomiting- and the diseased gastric fluid, which contains a large proportion of hydro- chloric acid, is also thus brought in contact with them, acting upon them with great violence. After food commingled with this secretion is ejected from the stomach, the teeth will be found eroded over all their surfaces. Dyspeptics will appreciate this re- mark. In such cases, if the teeth are not of superior organization, they are destroyed in a short time. Their surfaces thus roughened, afford a lodgment for foreign substances on all parts. < The most common agents, however, that injure the teeth, are originated in the mouth, by the decompo- 58 CARIES OF THE TEETH. sition of animal and vegetable matter. By this pro- cess, elements are eliminated, that form new combi- nations, and these operate as refined instruments in the destruction of the teeth. Favorable conditions exist in the mouth for such decomposition, and also for such new combinations ; for there is a sufficient amount of heat and moisture; and both of these, especially the former, facilitate the action of any acid upon the dentine. The character of the saliva and mucus will very much modify the decomposition of foreign substances in the mouth. If these secretions are both acid, the decomposition will be much more rapid, and more potent in its effect. Again, it is sometimes the case that the salivary glands are comparatively inactive, except when spe- cially excited, and yet the mucous glands still effi- cient, eliminating their secretion ; so that the mouth assumes an acid condition, because there is not saliva sufficient to neutralize the mucus; in which condition decomposition of foreign substances would be greatly accelerated. There are many cases, however, in which the flow of saliva is copious, and yet the decay very rapid ; which is in consequence of an acid con- dition of both secretions, or of a rapid decomposition of foreign substances in the mouth. There are acids taken with the food that act di- rectly upon the teeth ; as acetic acid, or vinegar. Professor Westcot says : " Acetic and citric acids so EXCITING CAUSES OF CARIES. 59 corroded the enamel in fortyeight hours, that much of it was easily removed with the fingernail." And " Malic acid, or the acid of apples, in its concentrated state, also acts promptly upon the teeth." Now, these acids, in the use of many kinds of food, are brought into frequent contact with the teeth. In the manufacture of vinegar, sulphuric acid is often employed; so that in this article of food we have that acid either alone or combined with the acetic, the former acting with greater energy upon the teeth than the latter. Acetic acid also facilitates the de- composition of food retained in the mouth, and thus reproduces itself in abundance. After eating apples that contain a great amount of malic acid, the teeth will be found corroded over all their surfaces. This acid, as well as the others, af- fects the enamel somewhat, and when the latter is very thin, though it may not be all removed from any particular point, yet its integrity will be de- stroyed, so as to be readily fractured, thus admitting injurious agents in contact with the dentine, which is much more susceptible of injury from acids than the enamel : points imperfectly protected by this are vio- lently attacked by acetic, malic, and sulphuric acids. In decayed cavities these agents produce rapid re- sults. They should be as much as possible avoided, and, when necessarily used, should be removed from the teeth by cleaning with great care. It would be 60 CARIES OF THE TEETH. safest to employ some neutralizing agent after the use of any acids with food. During mastication, there is an increased secretion of saliva, which, if in a healthy state, will tend to neutralize any acid that may at the time be present, and also, by its flow, to remove foreign substances from the mouth. Salts may be decomposed in the mouth, and their acids act upon the teeth; as when the acid of the salt has a stronger affinity for any element of the tooth- bone than for the base with which it is combined. Many medical preparations contain agents peculiarly deleterious to the teeth ; acids being especially in requisition for these, and not in homeopathic dilu- tions, either. The acids most commonly thus admi- nistered are the hydrochloric, the nitric, the sulphu- ric, the acetic, the tartaric, and the citric, any one of which will produce direct and rapid decomposition of the dentine, even when unaided by the temperature of the mouth. These acids are often administered by physicians, without any regard to their nature or their influence upon the teeth. Sometimes, however, they are given through a tube; though this method generally does not amount to much as a precau- tionary measure, for in most instances the fluid comes in contact with all parts of the mouth. A subse- quent rinsing of the mouth with water effects only a dilution, not an entire removal of the acid. In order wholly to counteract their injurious influence upon EXCITING CAUSES OF CARIES. 61 the teeth, an alkaline solution should be used after the administration of such medicines. Galvanic action is a cause of decay of the teeth, only so far as it is a means of decomposing com- pounds which are in the mouth, and the elements of which, according to the laws of affinity, form other compounds, some of which are highly prejudicial to the teeth. The elements hydrogen, nitrogen, and oxygen, may thus be set free from animal and vege- table substances, when they will at once seek other elements with which to combine ; and the character of the combinations will be determined by the nature of the elements, and by the attendant circumstances. These compounds will frequently be of an acid char- acter. Such an arrangement may exist as will maintain a constant galvanic action, whose legitimate effects will be as constant upon the teeth ; and this ceaseless process cannot but make its mark. It is a favorable arrangement for galvanic action when there are two or three kinds of metals in the mouth at once, par- ticularly if these are such as differ in their affinities for oxygen. In some cases three or four kinds of metals are employed in filling teeth of the same mouth ; in some, fillings of one metal and a plate of another; and in others, plates of so few carats are used that they oxydize rapidly in the mouth, without the aid of any other metal. 62 CARIES OF THE TEETH. COMPARATIVE LIABILITY TO DECAY. All classes of teeth are not alike liable to decay. Their difference in this respect may arise from a dis- similarity in their organic structure, the best organized being the most capable of resisting disease; or from a concentration of the destructive agency upon the tooth first affected. The first molars are much more liable to decay than any other teeth, since they are less perfectly developed than those formed at a later period of life. They are the first permanent teeth irrupted, and are subjected to all the irritating con- ditions consequent on the removal of the temporary, and the irruption of the other permanent teeth. But these conditions, in many cases, produce no apparent injury upon them, they maintaining their integrity till all the other permanent teeth are irrupted, and then decaying earlier than any others. In such cases, the decay is a result of influences more efficient than those occurring on the irruption of the other teeth. After the first, the second molars are most subject to caries ; and after these the second bicuspids. The latter two classes doubtless are so subject, more from the facility they afford to the lodgment of deleterious substances, than from a relatively imperfect organiza- tion. Besides, from six to fifteen years of age, the COMPARATIVE LIABILITY TO DECAY. 63 teeth are less appreciated and less cared for than at a later period of life. The next most liable to decay are the third molars. Then follow in order the first bicuspids, the lateral incisors, the central incisors, and the cuspids. Below are appended, in tabular form, one thousand cases of decayed teeth, as observed under ordinary circumstances, exhibiting the number and per cent, of these in each class : — 26, or 2A per cent., in central incisors. 38, or 3f " in lateral incisors. 24, or 2$ " in canines. 87, or 8f " in first bicuspids. 134, or 13| " in second bicuspids. 370, or 37 " in first molars. 218, or 22f " in second molars. 102, or 10J " in third molars. Of these, a large proportion were removed for relief from disease originating in caries of the dental tissue. In general, the superior teeth are liable to decay earlier and more rapidly than the inferior. CONSEQUENCES OF CARIES. It is here proposed to refer only to some of the more common results of this affection, one of the most obvious of which is the exposure of the pulp of the tooth; on which exposure, disease ensues, and 64 CARIES OF THE TEETH. finally death. During this diseased condition of the pulp, there occurs that very peculiar sensation com- monly denominated toothache. As well as the destruction of the pulp, the entire destruction of the crown of the tooth is the inevitable consequence of caries, unless this is interrupted in its progress. After the destruction of the pulp and the lining membrane, the external periosteum in many cases becomes involved, the affection being but an exten- sion of that which destroyed the internal periosteum. Inflammation and suppuration are of common occur- rence, by which a discharge is established from be- tween the margin of the gum and the neck of the tooth, or through a fistulous opening in the process and the gum, as is the case when an abscess is formed at the point of a root. A diseased condition of the alveolar process is, in many instances, produced by diseased and dead teeth ; necrosis and an exfoliation of considerable portions being sometimes the effect. Indeed, extensive caries of the jaw is occasionally thus produced. Disease of the antrum, too, is very generally induced or greatly aggravated by the same cause. Tumors, sometimes of a malignant character, connected either with the bony or with the soft parts, not unfrequently spring from this source, particularly in constitutions of a cancerous diathesis. Great nervous derangement may result, either in whole or in part, from decayed CONSEQUENCES OF CARIES. 65 teeth, as does very frequently facial neuralgia, which is sometimes confined to a single nerve-branch in the immediate vicinity of the irritating cause, sometimes ramified over the whole side of the face and head, and occasionally spread much farther, so as even to implicate the shoulder and the arm. Neuralgia of these, extending down to the hand, is often found to be instantly relieved by extraction of a diseased tooth ; and any operator of much observation can call to mind numerous instances in which facial neu- ralgia has been thus relieved or wholly cured. This affection of the face, however, does not always origi- nate in diseased teeth ; though there is little doubt that, in a majority of cases, it rises wholly or par- tially from this cause. Inflammation of the mucous membrane of the mouth, is a common result of diseased teeth ; and it is liable to extend to distant parts of this membrane, and occasion greater difficulty than in the mouth, as would especially be the case when there is an irri- table condition of the throat and bronchia; and the esophagus and stomach would not be exempt. In what degree such an implication of the respiratory and the digestive apparatus is referable to diseased teeth, it may not be easy to determine ; but it is impossible that a number of such teeth, involving in their disease all the ramifications of the facial nerves and the whole mucous membrane of the mouth, could 66 CARIES OF THE TEETH. remain there with impunity. And besides this direct influence on the lungs and stomach, diseased teeth are constantly emitting offensive odors, which are taken in by inhalation, and offensive matter, which is swallowed with the food. TREATMENT OF CARIES. In the rational treatment of caries, the first con- siderations are the nature and peculiarities of the obvious predisposing causes ; whether these are con- stitutional or local; and if constitutional, whether they are such as can be modified by therapeutic treatment of the general system. If the latter, such treatment should be adopted as will bring about the most perfect state of health, so as to obviate as far as possible all conditions favorable to decay, by securing a healthy state of the mouth in all its parts — as the gums, the mucous membrane, the salivary glands. The teeth should be kept free from all deposits and accumulations of whatever character; for, though some of these may not affect the teeth directly, yet they induce disease of the surrounding parts, and thus indirectly exert a pernicious influence upon them. The foregoing remarks, however, refer rather to the prevention of decay than to its treatment after it actually exists. Yet they are, on that account, none TREATMENT OF CARIES. 67 the less important, since here, as elsewhere, preven- tion is better than remedy. But they apply to such prevention as well after decay has commenced as before, if the ultimate object is a preservation of the teeth. After the first attack, the teeth are always more vulnerable, and less capable of resistance. When decay has attacked a tooth, the treatment depends upon the nature and extent of the disease. Rapid decay requires more prompt and energetic treatment than that of slow progress. Remedies that would be appropriate and efficient in the one, would be quite inapplicable to the other. The per- sistence of caries is not always in proportion to its rate of progress. We sometimes find teeth in which the decay is not advancing rapidly, and thence are led to conclude that it may be easily arrested ; the affected part, if superficial, is removed, and the den- tine finely polished; and yet, after a time, decay again attacks the tooth at the same point. Or, where the caries has penetrated the tooth, so that it re- quires filling, though it is skillfully filled, and the plug and tooth carefully polished, yet in many in- stances the dentine soon softens about the border of the plug. The extent of the decay will suggest the mode of treatment. Superficial caries on some parts of the teeth may be remedied and removed by cutting away the portion implicated in the disease, dressing with a 68 CARIES OF THE TEETH. fine file, polishing with Arkansas, Scotch, or rotten stone till the filemarks disappear, and then applying the burnisher very thoroughly to the entire surface operated upon. Afterward, the most careful atten- tion to cleanliness is requisite, to prevent a recur- rence of the attack. This treatment is applicable to decay upon proximal surfaces ; but in the depressions of the masticatory or buccal surfaces of the molars, and on the labial surfaces of the front teeth, it can not be employed. Sometimes the dentine, at points where it is ex- posed, gives warning, by acute sensitiveness, of threatened decomposition, before there are any other indications of it, thus evidencing the presence of some very irritating agency promotive of decay. Such points should receive prompt and strict atten- tion, and the increased sensitiveness be immediately subdued; as it may be, by the use of some prepara- tion that will counteract the exciting influence — some dentifrice or lotion containing an alkali; or a rubbing of the sensitive surface with a smooth steel burnisher, will in many cases effect this object, and prevent the development of decay. It has been suggested that the character of the caries may be modified by the local application of therapeutic agents — that the rapid decay may be changed to the slow — and this, too, without regard to the attendant circumstances, such as the condition TREATMENT OF CARIES. 69 of the secretions of the mouth, the causes producing the disease, etc. ; and various such agents have been proposed. It is held that by an application of the nitrate of silver, the white, rapid decay being changed to that of a dark color, becomes of less rapid progress. But there is no very palpable principle on which this agent can be supposed to operate to arrest caries. It is generally conceded to be injurious to a healthy tooth ; how, then, it becomes beneficial to one decayed, it is not easy to perceive. The notion may have originated in the fact that, after the application of nitrate of silver, the cavity turns dark, or black ; and this color being naturally associated with the slow form of decay, it may have been concluded that it might be thus associated by artificial means. This conclusion, however, is fallacious; for the coloring matter being the oxycl of silver deposited on the walls of the cavity, is wholly foreign, and holds no necessary relation to the kind of decay, or to the agency producing it. The deposit may possibly serve as a temporary shield to the dentine beneath, but only temporary ; whereas, on the other hand, it will be remembered that nitric acid is liberated by the decomposition of the nitrate, and operates destruc- tively upon the tooth-bone. An ethereal solution of the terchlorid of gold has also been suggested as a preventive application. Its operation would be much the same as that of the nitrate of silver, and equally 70 CARIES OF THE TEETH. inefficient. Preparations to neutralize and counteract the effects of deleterious agents upon the teeth have been recommended as topical applications. These are such as possess alkaline properties. But anything of this kind would require frequent application ; in- deed, it would be necessary to keep the affected part constantly under its influence, as long as the sur- rounding conditions continued to favor decay. Though nothing of this kind can be relied upon permanently to arrest caries, }'et, in many instances, much benefit is to be derived from local treatment. Alkaline topical applications will, in many cases, alleviate the most acute sensitiveness of the dentine ; accomplishing this, no doubt, by their neutralizing influence upon the irritating agents. Many opera- tors employ simply the bicarbonate of soda for this purpose, with the happiest results. As an other class of topical applications to check or modify caries, those have been suggested, which will form an insol- uble compound with the gelatinous or animal portion of the tooth ; such as tannin and some of the essen- tial oils. The only effect of these, however, is, to form a shield or protection over the structure be- neath : there is, of course, no change effected in the conditions or agencies which produce the decay. CHAPTER III. GENERAL REMARKS ON FILLING. The importance and value of the operation of fill- ing are obvious, from various considerations. It is one that is in frequent requisition. It is the only treatment for deepseated caries : by it, the disease is arrested and the lost part restored, so far, at least, as it can be by a foreign substance. There is no mate- rial similar to that destroyed — no substance possess- ing the characteristics of the lost portion of the tooth — with which to effect the restoration. Under favor- able circumstances, the operation of filling is efficient in arresting caries and restoring the lost portion of the tooth. In order, however, that it be permanent in its character, the case needs to be attended with favorable conditions, and the work to be thoroughly done. But, two similar operations, both equally well performed, may result very differently as to ultimate success in preserving the teeth to which they may have been applied ; the one effectually preventing further decay, and the other seeming to interpose to 72 GENERAL REMARKS ON FILLING. it but little obstacle. Indeed, the probabilities of such success in different operations, equally well ac- complished, cannot be calculated, without consider- ing a variety of circumstances, such as differences in constitutions, in states of health, in previous and sub- sequent habits. The filling of the teeth is predicated upon the na- ture of decay, upon the fact that the lost portion will not be restored by nature, and upon the fact that caries is an effect of external causes, and not of any cause within the tooth itself. If the cause of caries were alone within the tooth itself, then filling would not be its rational treatment. The organic structure of the teeth is of such nature that no change will take place in it, independently of external influences. Any organ possessing sufficient vitality and circula- tion to be susceptible of disease and decomposition, independently of external influences, possesses recu- perative power enough to restore to itself a lost part; and if dentine could be decomposed without external agents, the introduction of any foreign substance whatever into the cavity, would certainly not arrest the decay, but most probably would accelerate it. If it is true that decay of the teeth ever originates in constitutional causes, then the treatment should be constitutional, and not local. The filling of teeth, then, is based upon the ina- bility even of healthy dentine to resist the encroach- GENERAL REMARKS ON FILLING. 73 ment of decay. As preliminary to the operation, all the circumstances, both direct and collateral, should be carefully noted in every case, and the course of treatment should conform to the indications thus ob- served. The constitution, temperament, and health of the patient ; the peculiarities of the teeth ; their susceptibility of decay ; their present condition, and that of the parts about them; the periosteum, the gums, the mucous membrane, the secretions of the mouth, the saliva, and the mucus, should all be closely considered ; for only on a correct diagnosis can a proper treatment be based. Every operation should be performed as completely as, under the cir- cumstances, is possible. Indeed, every step in the operation should be perfect, before a successive one is attempted. All the instruments employed should be unexceptionable in material, form, and condition ; inferior instruments should find no place in the case of the dental operator. The material for filling should be of the best quality, and prepared in the best possible manner. Not that material for filling should be prepared in only one way ; for some mate- rials, gold for instance, may be prepared in three or four different forms, each perfect in its kind, and effi- cient in the hands of the expert manipulator. While with instruments and material all in the most perfect condition, and with a thorough cognizance and appre- ciation of all the attendant circumstances, our most 74 GENERAL REMARKS ON FILLING. skilful operators barely attain success, need we be astonished that the man ignorant of all these circum- stances, and possessed of only a few crude, ill-condi- tioned instruments and materials, the nature of which he does not understand, fails in almost every essay ? Much depends on therapeutic treatment; not, in- deed, to restore parts already lost, or to restore to health parts much diseased, but to avert a tendency to disease in parts but feebly organized. This treat- ment may be either constitutional or local, or both ; but constitutional when there is indicated any idiosyncrasy favorable to decay. If, however, the whole difficulty is local, topical treatment only is re- quired. What the special treatment should be in either case will be more fully considered hereafter. Comparatively little can be accomplished by local ap- plication to the substance of the tooth ; but the parts contiguous, as the gums and the mucous membrane, may be thus treated, with an assurance of more signal results. Though in the teeth nature does not assist to re- store a lost portion, as in those parts more highly organized, yet, to compensate in some degree, the de- structive process is far less rapid in the former than in the latter. The general surgeon depends much upon nature for the success of his operations; for, though he perforin them unskilfully, yet the kind MATERIALS FOR FILLING. 75 energy of nature is always present to assist him ; but in this specialty the practitioner must necessarily de- pend more upon his skill, and less upon the curative efforts of nature. MATERIALS FOR FILLING. In the selection of materials for filling teeth, there are some important considerations that should be kept constantly in view ; the first and principal of which is to choose that kind which will protect the tooth from further decay — protect the affected part against the influence of those agencies on which the disease depends. A material or class of materials should be selected that would not, under any circum- stances, operate either as a local or a constitutional injury. There are several properties that materials for filling teeth should possess, one of the most im- portant of which is indestructibility. This term is technically applicable only to compounds; but we venture here to expand its sense so as to indicate by it an integrity of substance as well in a simple as in a compound material ; for, considered with reference to the purpose of filling, a combination of the simple with another substance, is as much a destruction as is a decomposition of the compound. Any substance, whether simple or compound, that will not maintain its identity and integrity when subjected to any con- 76 GENERAL REMARKS ON FILLING. ditions of the mouth, is wholly unfit to use as a ma- terial for filling. If compounds are employed, they should be such as would not be affected by the secre- tions of the mouth, by its temperature, or by its con- ditions. A mere mechanical mixture would not be an appropriate material ; and all compounds of the metals, so far as we are familiar with them, are unfit for this purpose, by reason of the facility with which they are destroyed in the mouth. The next most important property of a material for filling, is, adaptability ; by which is meant a capa- bility of being w r rought into suitable shapes for the purpose, — a facility of being applied and conformed to the parts upon which it is to be placed. There are substances that would be entirely indestructible in the mouth, and that would be very desirable in other respects as materials for filling, yet that are altogether worthless for this purpose, from lack of adaptability. Quartz, if it possessed this property, would be valuable as a material; but as yet there has been discovered no method of preparing it in an available form. On the other hand, many things possess the property of adaptability, that are lacking in some other important particulars. The next important property is, hardness. A material may possess all the other suitable qualities, and yet be too soft. A material should be hard enough not to be broken by any pressure or friction MATERIALS FOR FILLING. 77 liable to be applied. This property is especially desi- rable for fillings in the masticatory surfaces of the molars and bicuspids. It would, however, be admis- sible to employ a softer material for filling cavities in the proximal surfaces of the teeth, provided it per- fectly excluded all foreign substances. Again, a material should be as nearly as possible a nonconductor of heat, particularly for filling sensi- tive teeth, or those liable to become so under the influence of slight causes. Extreme variations of temperature will, in most instances, aggravate sensi- tiveness, and, in susceptible cases, produce it ; and, if the irritation is continued, the result may be necrosis. Gold, which possesses the largest number of desirable qualities as a material for filling, is in this respect very defective, being one of the best conductors of heat. To obviate this defect, some nonconducting material is employed between the gold and the sensi- tive portion of the tooth. The nerve is liable to be affected by sudden and extreme changes of tempera- ture, transmitted to it through a gold plug. In the next place, a material should be susceptible of being welded, or united into a solid mass. The permanency of an operation depends very much upon this quality. A filling having the different pieces which compose it perfectly consolidated, will be much more durable than if effected with a mate- rial in which this cohesive property is lacking, can 78 GENERAL REMARKS ON FILLING. be made with greater facility, and will be better and longer retained; and mainly because such a filling cannot be destroyed piecemeal. Noncohesive mate- rial is retained by the general form of the cavity, which is to be shaped so as to bind all the pieces together, and thus hold them in place ; but a sub- stance that will weld, requires only two or three good retaining points, angles, or pits, properly .situ- ated, in order to be firmly and permanently fixed in a cavity of any form. Color. — An other desirable property of a material for filling, is, such a color as shall best harmonize with that of the teeth, particularly if the}' are in front. In this respect, all the metals are objection- able; though gold is probably less so than any of the others, the objection to this being not so much in its color as in its luster; which objection, however, may be partially obviated by the kind of finish given to the work. In teeth of certain shades — semitrans- parent bluish white, for instance — gold, for exposed fillings, is very objectionable; indeed, in some cases, as unsightly as would be an entire absence of the tooth ; and, in such instances, the darker metals would of course appear much worse. For such teeth, some mineral substances would be most desirable. Most of the materials employed for filling are metallic; only a few nonmetallic substances have been used, and these rather by way of experiment, MATERIALS FOR FILLING. 79 than with any hope of permanent success. Of the metals, gold possesses more of the indispensable pro- perties than any other ; but the following have all been used for filling : lead, tin, silver, platinum, gold, and amalgam. In the preparation of the latter, gold, silver, platinum, tin, bismuth, antimony, cad- mium, zinc, and mercury, have been employed. Lead. — This metal, in the early history of the pro- fession, was used to some extent for filling, though it possesses but few of the requisites for that purpose. The principal quality which recommended it, is its adaptability ; but it is quite too soft for permanent fillings in the masticatory surfaces of the molars. It is easily wrought into foil and welded into mass in the cavity, but is rapidly worn down by mastication, and its integrity readily impaired by the influence of peculiar conditions of the mouth ; much more readily, indeed, than that of tin or silver. Acetic and other acids act upon it with considerable energy in the mouth, being there subjected to both heat and moist- ure. By exposure to air and moisture, it is soon coated with carbonate or protoxyd of lead ; and this change is effected much more readily in the mouth. Lead is also objectionable in color — especially for fill- ings in the anterior teeth — it being darker than the other metals employed for the purpose. It is, how- ever, a less perfect conductor of heat than some others that are in far more extensive use. 80 GENERAL REMARKS ON FILLING. Tin. — This metal has been, and is even yet, much employed as a material for filling. It is easily wrought into foil, and in that condition is readily adapted to the purpose, by reason of its softness and pliability. Fillings can be made with it in all cases in which nonadhesive gold foil can be used, to much of which, indeed, it can, by skillful manipulation, be made superior in adhesive property. Its quality, however, is greatly dependent on the manner of its manufacture. It is harder than lead, and in many cases hard enough for permanent fillings : we have known it retained in crown cavities of the molars, effectually preserving the teeth, for fifteen years. In favorable conditions of the mouth, it is not materially changed, not oxydizing easily, and not readily uniting with any substances liable to be brought in contact with it. But in an unhealthy mouth, with the secre- tions in an abnormal condition, and the teeth neglected, tin fillings are very rapidly destroyed. Such a change may take place in the mouth, as will in a little time destroy tin fillings that had long remained in good preservation ; and hence this mate- rial is not entirely reliable in any case, since such change may at any time occur. Some cases seem- ingly favorable to its use, are found, on examination, to be otherwise ; and in almost any mouth in which there is a large proportion of mucus secreted, it can not be depended upon for permanency. Its color MATERIALS FOR FILLING. 81 renders it unfit for the anterior teeth. It is a less perfect conductor of heat than gold ; on which ac- count it is frequently employed where the latter metal can not be. It should not be used in a tooth in which there is an other metal ; notwithstanding some economical dentists do sometimes use it to fill the interior of large cavities, placing upon it a covering of gold. This method is objectionable in two parti- culars : first, the tin is softer than the gold, and under much pressure yields beneath it, so as to destroy the integrity of the filling ; and second, when the fluids of the mouth come in contact with the two metals, a chemical action is induced, by which the tin is rapidly oxydized. It is for this reason that no two metals should be applied to the same tooth ; as, for instance, tin for filling a tooth round which there is a gold clasp, or in contact with which is a gold plate. Finally, the use of this material should be deter- mined not only by all these circumstances, but also by the constitutional predisposition of the patient, and the character of the teeth, which should be dense and well organized, in order to render it at all admis- sible. Silver. — This metal was formerly in more extens- ive use as a material for filling, than it is at present. It is not, for this purpose, superior to tin in any par- ticular, except in being somewhat harder; and in some particulars it is inferior, being quite as de- 82 GENERAL REMARKS OX FILLING. structible in the month ; more easily affected by cer- tain agents, such as nitric acid, nascent chlorine, etc.; less pliable and less adaptable; more difficult to work into foil; not so readily formed into fillings; and pos- sessed of much less cohesiveness, being almost un- weldable by the ordinary method of manipulation. Silver is a better conductor than tin, and would therefore in some cases be more objectionable. The saliva is often in such a condition as to act upon it with great energy and rapidity. Its color, too, is ob- jectionable. With these disadvantages, its use has very properly been wholly abandoned. Platinum. — This metal has been but little used for the purpose of filling; though it possesses some of the requisite qualities in a very high degree ; as, for instance, indestructibility, in which property it is su- perior to gold. In some other respects, however, it is very deficient; it has not as yet been wrought into any form in which it can be welded with facility ; it is difficult to work into foil ; and, when it is put into this form, it possesses a stiffness and harshness that render its adaptation and condensation almost im- practicable. It is more on this account, perhaps, than on any other, that it has been so little employed for the purpose of filling. It has also less adhesive- ness than gold, and much sooner parts with this prop- erty. Slight crumpling or bending serves to stiffen it so as to destroy its applicability. Good fillings MATERIALS FOR FILLING. 88 may be made of well prepared platinum sponge, re- cently annealed. It requires skillful manipulation, however ; for the least moisture destroys its cohesive property entirely. It is quite as good a conductor of heat as gold, and on this account equally objectiona- ble. In the respect of color, too, it is undesirable. Platinum should never be placed in close proximity to tin fillings, or to gold plate or clasps of few carats. It is not now, however, used in filling at all, except for experiments. Gold. — Of all the metals that have as yet been used for filling teeth, gold possesses more of the requisite properties than any other. It is more inde- structible than any other, and sufficiently so for all practical purposes. Twenty-carat gold is very sel- dom affected by any agencies with which it is brought in contact in the mouth ; pure gold, never. In the filling of teeth, there are two objects to be aimed at : one, a sufficient hardness to withstand the wear of mastication ; the other, a thorough protection to the cavity against all foreign substances. For the attainment of the first of these, gold is not all that could be desired; yet it is, perhaps, as efficient in this respect as any other metal that can be employed. But the second object gold accomplishes perfectly; that is,, so long as the filling maintains its integrity; after it has partially worn out, it thus far fails, of course. In adaptability, too, gold is superior to any other metal. 84 GENERAL REMARKS ON FILLING. It can be elaborated into a variety of forms, with any of which very good fillings can be made. It can be perfectly conformed to any shape of surface, however irregular. A tooth that can be filled at all, can be filled with gold. This assertion was made a number of years ago ; and if it was true then, it is much more true now ; for then the adhesive property of gold was not employed at all, or even recognized as available ; but now, this property has been rendered efficient and practicable. Then, our best operators did not aim to unite the different portions of gold of which the fill- ings were composed. The idea that such consolida- tion could be effected, seemed never to have entered their minds. Indeed, with the instruments and the method of manipulation then employed, this adhesive property could not have been made available ; but as it came to be recognized, the instruments and the manipulation were adapted to the purpose. For- merly, an ordinary gold plug when removed from a cavity, would be separated into as many pieces as originally composed it ; but now, when adhesive gold is skillfully used, the mass composing a filling can not be divided into its original parts, but may be wrought into plate, wire, or foil. Nonadhesive gold — the modification in which, till recently, it was always employed — would not weld, even under great press- ure ; but, in the mode in which it is now prepared, it will weld readily and thoroughly. There are cer- MATERIALS FOR FILLING. 85 tain requisites essential to this welding property of gold : if it is in the form of foil, it must not present a smooth, planished surface ; it must be annealed after hammering, in order that its ultimate particles may be in the best condition for cohering; it must be entirely free from all deposits of foreign substance; and it must be kept from exposure to the atmos- phere. Gold is a good conductor of heat; and this is the chief objection to it as a material for filling. As to sensitive teeth, this is a very serious objection, in some cases necessitating the employment of non- conducting materials with it, and in others preclu- ding its use altogether. The color of gold, however, is seldom an objection to its use ; though it some- times renders it unsuitable for fillings in the front teeth. But this objection has been already adverted to. Various Preparations of Gold. — And first, of the manufacture of gold foil. For this purpose, pure gold is used ; for procuring which, various methods are employed. But the most common of these are insufficient for the production of gold absolutely pure. It is, however, deemed irrelevant here to detail the process by which this end is attained : it is enough to premise that, for the manufacture of the best quality of foil, perfectly pure gold is indispensable. The gold is cast into an ingot about an inch wide, which 86 GENERAL REMARKS ON FILLING. is placed between a pair of rollers, and rolled down as thin as practicable, the piece, while rolling, being frequently annealed. It is then cut into squares, which are inserted with wooden pliers between vel- lum leaves, a hundred and sixty or seventy in a pack. Over this pack two pockets are drawn, in- closing it completely. The pack then, while it is carefully annealed, is hammered on a marble block, with a hammer weighing twelve or sixteen pounds, till the leaves are spread out to the full extent of the pack. Much experience and skill are requisite to the proper accomplishment of this part of the work : by a single unskillful stroke of the hammer, a whole pack might be spoiled. Gold foil is numbered according to the grains con- tained in each leaf, ranging from 2 to 30. The most common numbers are, 2, 3, 4, 5, 6, 8, 10, 15, 20, and 30, the smaller, from 2 to 6, being in most frequent use. It has heretofore been a desideratum to obtain gold foil perfectly uniform ; but some few manufac- turers now seem to have attained this perfection. Crystal Gold. — This form of gold was introduced to the profession about five years ago. Some experi- ments in this direction, indeed, had been made as early as 1825, by C. Ash, of London, and again in 1850, by Dr. S. A. Main, of New York. Their prep- arations, however, were simply precipitates, and nothing more. But in 1853, Dr. A. J. Watts, of MATERIALS FOR FILLING. 87 Utica, New York, obtained letters patent for his prep- aration of gold for filling teeth. This preparation was at first denominated sponge gold, but after some modification, received its present name. There are numerous formulas by which preparations of crystal gold may be made ; but so far as we are acquainted with them, they are all embraced in two general methods : the one, to obtain simply a precipitate of the metal, adaptable to the filling of the teeth ; and the other, to combine this precipitate with mercury, and obtain a definite crystallization. For the prepa- ration of the sponge or crystal gold, the absolutely pure metal is required. This is dissolved in nitro- muriatic acid, the gold being added till the solution is saturated. Various materials may be used to pre- cipitate it, the most common of which are sulphate of iron and oxalic acid, the latter on some accounts being preferable. The character of the precipitate will be determined, in a great degree, by the manner in which the precipitant is added : if slowly, the pre- cipitate will be more fibrous, or structural. A preparation may be made by introducing the precipitant gradually, and then carefully washing the precipitate, and heating almost to redness. For per- fect crystallization of the gold, combine the precipi- tate with from six to twelve times its weight of pure mercury, let it stand a short time, subject to a gentle heat, and then remove the mercury with dilute nitric 88 GENERAL REMARKS ON FILLING. acid. Afterward wash the nitrate of mercury from the gold ; place the latter upon a slide, and bring it up to a full red heat in a muffle, and the gold is then in a condition to be used for filling. This is about the formula on which a patent was granted to A. J. Watts. The preparation possesses some advantages over gold foil : it is as readily introduced ; it is more capable of thorough consolidation; it has, besides the cohesiveness of foil, the additional property of inter- lacing its crystals one with another, by which prop- erty, even without cohesion, the pieces of a filling can be firmly united ; and it takes a better hold upon the walls of the cavity, to which it presents edges and ends, so as to be more thoroughly adapted and fastened. Amalgam. — By this term are designated all those preparations formed by a combination of mercury with various other metals ; most frequently with sil- ver and tin, but occasionally with gold, platinum, bismuth, cadmium, zinc, and lead. The several form- ulas for amalgam need not here be specified. The kind most in use is prepared by melting together and carefully mixing pure tin and silver, filing this mixt- ure, when cooled, into dust, combining the latter with mercury in sufficient proportion to give the requisite plasticity, and then thoroughly washing the whole in alcohol or boiling water, to eliminate the oxyds formed by the combination of the metals. If MATERIALS FOR FILLING. 89 there is a redundance of mercury, it may be removed by pressing the paste in a piece of chamois skin. This preparation may in some cases be used for filling with considerable success; but in no case can it be relied upon as a durable material, its destructi- bility being no less than that of tin or silver in any circumstances, and being greater where all the mer- cury is not removed from the surface of the filling, and the surface not burnished down solid and smooth. Mercury oxydates with considerable rapid- ity when exposed to air and moisture, and with in- creased energy, under the influence of heat, especially when some acid is present. This facility of oxyda- tion is still increased when other metals are com- bined with the mercury. Oxydation of such fillings will in some cases be confined to the surface, wherever there is contact of moisture; in others, it will per- vade the whole mass, rendering it black and spongy throughout. Amalgam fillings, in a short time after their inser- tion, undergo a hardening process, caused mainly by evaporation of the mercury. The consequence is, either that the mass becomes porous, or that it con- tracts; the former, doubtless, in cases where the oxydation blackens through, and the latter, where it is confined to the surface. When a plug is in either of these conditions, the preservation of the tooth is very uncertain. On removing an ordinary amalgam plug 90 GENERAL REMARKS ON FILLING. that has been worn for some time, its entire surface will generally be found oxydized : and a tooth filled with this material generally becomes blackened, and its appearance ruined. To such objections against this material, an other is to be added in cases in which there are fillings or plate of platinum or gold : galvanic action will be established, in a degree proportionate to the proxim- ity of the metals and the condition of the secre- tions. This may occasion much mischief. Some constitutions are very susceptible of the influence of mercury ; and a gradual decomposition of several amalgam fillings in the mouth, may seriously impair the general health. Therefore, before this material is ever employed, the health, temperament, habits of the patient, should be carefully noted ; for these and other circumstances may often indicate its inadmissibility. So great and so numerous are the objections to this material, that it is but little used by reliable opera- tors. Its adaptability is the main property on which are based the arguments in its favor : it is easily applied, and consolidates with considerable hardness. It is affirmed, also, that teeth which cannot be saved with anything else, may be filled with this, and made valuable. This, however, is not true since the em- ployment of the adhesive property of gold ; which property renders this metal equal in adaptability to amalgam. MATERIALS FOR FILLING. 91 Nonmetallic Materials. — Of the nonmetallic mate- rials experimented with for filling, there are not many worthy of any particular consideration. In- deed, gutta perch a and its preparations constitute the chief nonmetallic substances now used for this pur- pose, though some others have been employed. Gutta percha is useful for temporary fillings, and, under ordinary circumstances, sufficiently durable. It is valuable for filling those teeth which it may be desirable to retain only a short time, or those in which it may be necessary temporarily to protect a sensitive part against the influence of irritating agents, in order to restore it to health. Gutta percha is not readily decomposed by the fluids of the mouth, when they are in a healthy condition. In some instances, we have known it worn in the mouth for years, with but little change. But in cavities on the grinding surfaces of the molars and bicuspids, it will not withstand the wear of mastica- tion a great while, though long enough in most cases to subserve the purposes of a temporary filling. It possesses great adaptability : by simply being warmed over a spirit-lamp or in boiling water, it becomes plastic, and is with great facility introduced and con- formed to the cavity. It may be applied also in solution, being dissolved in chloroform till it ap- proaches a pasty consistence, then absorbed in a pledget of cotton, and introduced into the cavity; 92 GENERAL REMARKS ON FILLING. where the chloroform, evaporating, leaves the gutta percha as a filling. The only objection to this method is, the contraction consequent on the evapo- ration of the chloroform. Another property that renders this substance highly valuable, is, its non- conduction of heat, it being in this respect as nearly perfect as any other material employed. A preparation of gutta percha with mineral sub- stances, known as HUTs stopping, has, for the last four years, been extensively used for temporary fill- ings ; indeed, it has superseded simple gutta percha almost entirely. The aim of this preparation was to obviate two or three objections to pure gutta percha; as, its contractibility in the cavity, its softness, and its color. The composition of HUTs stopping is as fol- lows : With pure gutta percha in a plastic state, are mixed quicklime two parts, and quartz and feldspar one part each, which latter are reduced to an impal- pable powder, and kneaded into the mass as long as it will receive them without becoming brittle. Such is the formula given by the inventor of this prepara- tion ; though it is presumed that one of these mate- rials alone, namely, pulverized quartz, would be found entirely sufficient, since it is capable, by itself, of quite as much as is attained by all together. The addition of gold or platinum filings has been recom- mended ; but no advantage is thus gained. It was at first claimed for this material that it would serve for MATERIALS FOR FILLING. 93 permanent fillings ; but it was soon demonstrated in- sufficient. It was supposed, also, that it might be employed for partial fillings in large cavities, which could be completed with gold ; but for this, too, it was found impracticable, since it did not make a suf- ficiently firm foundation. This preparation is applied in the same manner as simple gutta percha, being warmed on a porcelain or metal slab over a spirit-lamp till sufficiently soft, and then packed into the cavity. It cannot be employed in the form of solution, nor should it be softened in boiling water. It may be conveniently prepared by dissolving the gutta percha in chloroform to almost a pasty consistence, then adding the mineral sub- stances, and putting it into a vessel suitable for the evaporation of the chloroform. It should be made so thick, that the silex would not fall to the bottom. When HUTs stopping or gutta percha is used, as soon as the cavity is filled, an instrument with the end nearly as large as the orifice of the cavit\ 7 , should be placed upon the filling, and retained there with con- siderable pressure till the mass is cool. We as yet know of nothing better for temporary fillings than this preparation of gutta percha. CHAPTER IV. INSTRUMENTS FOR FILLING. In describing the instruments for filling teeth, it will be convenient to take them somewhat in the order in which they are employed in ordinary prac- tice ; first referring to those which are used for cut- ting away portions of the teeth, for the purpose of separating them, and for dressing off the borders of cavities; then to those for removing decay and form- ing the cavities ; and finally to those for introducing, consolidating, and finishing fillings. The first, then, that claim our attention, are the HEAVY CUTTING-INSTRUMENTS. These are of the thick chisel shape. They should be of good steel, well wrought, and thoroughly tem- pered. Every step in the process of their manufac- ture should be most perfectly executed, so as to in- sure an edge that will cut not only dentine, but also enamel, which is the hardest animal substance. Va- rious sizes of the straight chisel form are required. HEAVY CUTTING-INSTRUMENTS. 95 In all cases they should be as thick as possible, with- out being thus impaired in their efficiency ; so firm that there may be no springing or tremulous motion under the pressure they are required to sustain. For separating front teeth, however, they must be thin enough to pass readily into the intended space, and about one fourth of an inch wide at the edge. (See Fie. 2. Fig. 2.) But, for separating bicuspids and molars, the instruments should be thicker and broader; as thick, indeed, as the respective intervals will admit. Fin. 3. (Fig. 3.) In some cases, they should have the edge oblique, as in Fig. 4. It is seldom that these instruments need any Fie. 4. curve. The straight form is the best, unless, as it rarely happens, the point to be operated upon can not 96 INSTRUMENTS FOR FILLING. be reached efficiently with it ; as, for instance, in a small mouth, a slight anterior curve will be required in the shaft of the instrument, to facilitate its ap- proach to the front proximal surface of a second or a third molar. (Fig. 5.) A heavy instrument, with a Fig. 5. sharp point and a lateral curve, is often efficient in opening up cavities and cutting down strong projec- tions of enamel. (Fig. 6.) This class of instruments Ficr. 6. we consider as valuable as any other in our case. Every operator should have at hand a sufficient va- riety to meet every demand. DRILLS. Bar Drills. — Of this indispensable class of instru- ments there are various forms. They should be manufactured of the best steel, and wrought with the greatest care. After having been forged as near the DRILLS. 97 proper size as possible, the bulb is shaped by dressing with a fine file, or by turning in a lathe; those made by the latter method being superior, and cut- ting much more smoothly; they do not catch and jar as do those of less regular form. After the bulb is formed, it is usually cut with a sharp-edged file. Fig. r. Of these drills, Fig. 7 represents a bur of a spher- ical form. Fig. 8 is cone-shaped, which may have Fig. 8. various degrees of bevel, terminating in a sharp point. Fig. 9 is of a cylindrical form, cut upon the sides and end. Fisr. 10 is in the form of a Fig. 9. wheel, cut upon the edge only, or upon both the edge and the end. The cutting upon all of these 98 INSTRUMENTS FOR FILLING. should be very regular and uniform. This should be made by machinery, though it is usually done by hand. Of these instruments, there should be a Pier. 10. variety in size, the smallest considerably less than the smallest cavity the dentist ever attempts to fill — that is, about one thirtysecond of an inch in diam- eter, and the largest about one fifth of an inch. Inclusive of these extremes, there should be about fifteen sizes of each particular form. These instru- ments are used for opening cavities. With them a more regular and perfect orifice is made in small and medium-sized cavities, than by any other method. They are also used. to some extent for forming the cavities, and even sometimes, in large cavities, for making retaining-points for a filling. Common Drills. — Of an other kind of drills, Fig. 11 represents one with a square point, beveled from Fie. 11. both sides, measuring from a half to a whole line in length, and attached to a small round shaft. The edges of the drills should be very hard, so that they DRILLS. 99 may cut with the greatest celerity. Of this kind, there should be about ten sizes, ranging in width from No. 15 to No. 25 of Stub's gauge. These are used mainly for forming retaining-points in cavities. Fig. 12 is the spear-shaped drill, the edges of Fig. 12. which are formed by dressing from both sides ; or, it may be, from only one, in which case it will cut only when rotating one way. This shape is employed principally for drilling out fangs for filling or receiv- ing pivot teeth. The burs and drills may be made of pieces of wire one and a half inches long, and fitted to a socket- handle that will accommodate a large number ; or of a continuous piece of large wire. The latter is the preferable method, since much time is consumed in changing them in sockets. The handles should be made with six or eight sides, and cut on each alter- nate side. In the use of these instruments, the socket-ring is almost indispensable. This is an open ring for the middle or the index finger, with a socket attached, in which rests the end of the handle of the 100 INSTRUMENTS FOR FILLING. instrument. (Fig. 13.) The drill is rotated commonly with the thumb and ringers. Fisr. 13. Drill-stocks of various forms have been invented, with the view of increasing the motion of the drill, of augmenting its power, or, especially, of bringing it to bear upon points inaccessible to the straight in- strument. Some of these stocks are very compli- cated; as, for example, that denominated Chevaliers Fi