key: cord-1016991-skfdgbxl authors: Hoshi, Kazuto; Ikebe, Tetsuro; Ota, Yoshihide; Kishimoto, Hiromitsu; Kurata, Takeshi; Kurita, Hiroshi; Sakamaki, Kentaro; Takenobu, Toshihiko; Harada, Sohei; Ogasawara, Toru; Tei, Kanchu; Kirita, Tadaaki title: Guide for Surgical Procedures in Oral And Maxillofacial Areas during Coronavirus Disease 2019 Pandemic date: 2021-10-28 journal: J Oral Maxillofac Surg Med Pathol DOI: 10.1016/j.ajoms.2021.10.007 sha: 4de4608557636110214fbc46b350874bbea2fcc7 doc_id: 1016991 cord_uid: skfdgbxl nan The coronavirus disease 2019 , was confirmed in China in December 2019 [1] and rapidly spread worldwide. As of January 2021, the cumulative number of infected individuals in the world was 80 million, with more than 1.8 million deaths (according to the World Health Organization(WHO)). The pandemic has affected not only the daily life but also clinical practice. The virus is transmitted from person to person through droplet infection or contact infection. In Japan, outbreaks of the infection (clusters) have been reported in general hospitals and nursing care facilities. Thus, during the period from March to May 2020, the so-called first wave, many dental clinics and hospitals limited the outpatient and inpatient care, to prevent the spread of infection. Although the number of newly infected patients transiently decreased from June 2020, it increased again from August and November 2020. In December 2020, the presumably highly transmissible variant (VOC-202012/01) that was spreading in the United Kingdom was also detected in Japan, and the infection is still spreading. Oral and maxillofacial surgeons, who examine and treat the oral cavity and its surrounding structures in daily clinical practice, are always exposed to the risk of infection through exposure to saliva, droplets, and aerosols containing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative virus. Fortunately, there have been no reports of transmission from patients to medical professionals during surgical procedures or treatment in oral and maxillofacial areas. However, in neurosurgery, cases in which medical professionals were infected during transnasal pituitary surgery have been reported [2] . The risk associated with surgical procedures and treatment among medical professionals of oral and maxillofacial areas is not J o u r n a l P r e -p r o o f necessarily revealed because sufficient data have not been accumulated. Given the incidence of infection during surgery in associated clinical fields, to promote prevention of infection, as well as provide sufficient attention to and control against exposure to the virus, in oral and maxillofacial surgeons, we present guide that should be referred when surgical procedures in oral and maxillofacial areas are performed. The guide includes items on preoperative preparation, preoperative assessment, decision on the performance of surgery, intraoperative equipment, and operating room environment. The guide intends to be used by all dentists and surgeons who perform surgical procedures of oral and maxillofacial areas in Japan, including the general practitioners and those working at general hospitals, medical, and dental school hospitals. The guide is applicable to all surgical procedures performed in the oral and maxillofacial surgery including tooth extraction, trauma, infection, tumor, inflammation, and congenital and acquired morphological abnormalities, regardless of the use or type of anesthesia. Because evidence has not been established on many aspects of COVID-19, this guide is not evidence-based treatment guidelines. Instead, they provide a summary of information and recommendations based on information that the Japanese Society of Oral and Maxillofacial Surgeons collected through extensive search. tissue, handkerchief, the front piece of a jacket, or a sleeve when they cough or sneeze. In the case of COVID-19, cough etiquette alone is insufficient to prevent infection because viral transmission from asymptomatic or pre-symptomatic patients has been reported. For this reason, "universal (community) masking," in which people always wear a mask regardless of whether they are symptomatic or asymptomatic to reduce the amount of droplets generated by infected individuals, is relevant. Although non-woven fabric is a preferable material for a mask, a double-or more-layered fabric mask is considered effective to a certain extent. In addition, proper wearing of a mask is important. For example, the nose should be covered, and a mask should be attached to the face without any gaps. Hand hygiene is divided into two categories: "hand disinfection" with rubbing-type alcohol-based hand sanitizers and "handwashing" with running water and liquid soap. In ordinary situations, hand hygiene should be practiced with "hand disinfection." When the hands are contaminated or suspected to be contaminated, "handwashing" should be performed. Appropriate rubbing-type alcohol-based hand sanitizers should be selected because some products may cause 'dry skin' depending on the effect of the emollient contained. Individuals who have trouble with the use of alcohol-based sanitizers because of allergy and other reasons should practice "handwashing." In this guide, gargling means "gargle" and "mouth wash/mouth rinse." Gargle is defined as "cleaning the pharynx and oral cavity by rumbling with liquid, which is spitted out afterward." The mouth wash/mouth rinse is defined as rinsing of the oral J o u r n a l P r e -p r o o f Aerosols generally refer to the dispersion of liquid or solid microparticles in the air. In terms of size, microparticles vary from approximately 1 nm to 100 μm. Aerosols measuring ≤2 to 3 μm are so light that they may not fall on the ground immediately but may float in the air for several hours. If microparticles contain pathogens, inhaling them through the mouth or nose may cause infection. Wear an N95 respirator, face shield/goggles covering the eyes, gown with long sleeves covering up to the wrists, surgical cap covering the ears, and surgical gloves. Avoid exposure of the skin as much as possible. Wearing an N95 respirator prevents the inhalation of droplets and aerosols. Medical-grade masks of KN95 should be regarded equivalent to N95 respirators. Wear PPE without an N95 respirator. Wear a conventional surgical mask, face shield/goggles covering the eyes, gown with long sleeves covering up to the wrists, surgical cap covering the ears, and surgical gloves. A simple PPE corresponds to PPE for surgery in conventional conditions. According to the operating room standards, a laminar flow ventilation system should be installed in an operating room beforehand. In an operating room with laminar flow J o u r n a l P r e -p r o o f ventilation, the surgeons and other medical professionals are exposed to a reduced risk of inhaling droplets and aerosols generated from the operative field. The surgeons and the assistants should stand more upwind than patients. It is essential to ensure that exhaust air containing aerosols does not reenter the operating room. Use intraoral (or surgical) suction devices to suck and dispose fluid waste, droplets, and aerosols generated during surgery. When intraoral (or surgical) suction devices are built into the facility, it is essential that they do not allow reentry of exhaust air containing aerosols into the operating room, and that their structure ensures safe disposal of fluid waste. When mobile devices are used, it is essential that their structure ensures safe dispersion of exhaust air through high-efficiency particulate air (HEPA) or other equivalent filters and safe disposal of fluid waste. HEPA filters need to be replaced regularly according to the specified usage. Use extraoral vacuum devices to suck and dispose scattered substances, droplets, and aerosols generated during surgery. When extraoral vacuum devices are built into the facility, it is essential that they do not allow reentry of exhaust air containing aerosols into the operating room, and that their structure ensures safe disposal of collected scattered substances. When mobile devices are used, it is essential that their structure ensures safe dispersion of exhaust air through HEPA or other equivalent filters and safe disposal of collected scattered substances. HEPA filters need to be replaced regularly according to the specified usage. Two weeks before surgery, instruct the patient on infection control practices, such as avoidance of non-essential outings, maximal avoidance of conversation, meeting, and eating without proper wearing of a mask in proximity with people other than family members living together, and avoidance of places with a high infection risk, such as hot spots. Instruct the patient to thoroughly practice cough etiquette, hand hygiene, and gargling after outings. On the day of surgery, let the patient perform "mouth wash/mouth rinse" with povidone-iodine at the shortest possible interval before surgery unless the patient is allergic (refer to 6. Appendix: Precautions for gargling) When preoperative assessment is performed, the area where the patient lives, works, or studies is classified as a potential zone, epidemic zone, or high communitytransmission zone, according to the incidence of infection. It is an area where patients with COVID-19 may potentially exist, although encountering those with COVID-19 is infrequent in daily clinical practice. As a guide, a J o u r n a l P r e -p r o o f potential zone is defined as a prefecture where the cumulative number of newly infected individuals* per 100,000 persons is <0.3, within the preceding week. It is an area with a high possibility of encountering patients with COVID-19 in daily clinical practice. As a guide, the epidemic zone is defined as a prefecture where the cumulative number of newly infected individuals* per 100,000 persons is ≥0.3, within the preceding week, but where a state of emergency is not declared. It is an area where the risk of nosocomial infection through surgery is high because a high incidence of community-acquired infections increases encounter with patients with COVID-19 requiring surgery in daily clinical practice. As a guide, the high communitytransmission zone is defined as a prefecture where the government declares a state of emergency or issues an equivalent travel restriction. * The number of PCR-positive individuals per 100,000 persons in the preceding week, as reported by the Ministry of Health, Labour and Welfare (by prefecture) https://www.mhlw.go.jp/stf/seisakunitsuite/newpage_00035.html When the area, where a patient works or studies, differs from the resident area, an area with a higher incidence of infection should be selected. In principle, the incidence of infection should be assessed at the prefectural level. However, if the incidence varies significantly within a prefecture, these criteria can be flexibly applied according to the actual situation. *Refer to figure: Preoperative assessment to be performed. Start performing preoperative assessment for COVID-19 3 days before surgery. Select the exact contents of preoperative assessment according to regional risk assessment. Classify the assessment results as positive or negative. When the preoperative assessment cannot be done, or when the results of their assessment are unavailable, such cases should be designated as untested. * Refer to figure: Surgical decision algorithm. When patients from a potential or epidemic zone have a positive assessment result, elective surgery should be postponed, or alternative treatment should be considered. When surgery cannot be postponed for emergency reasons (e.g., imminent danger to life due to massive hemorrhage, severe infection, airway obstruction; malignant tumor; trauma including skin/mucosal laceration requiring suture, maxillary or mandible fracture, alveolar fracture, and tooth dislocation/fracture), surgery should be performed as an "inevitable choice" for as short operative duration as possible. Patients with an untested result should be treated as patients with a positive assessment result. When the assessment result is negative, surgery should be performed. When patients from a high community-transmission zone have positive assessment results, elective surgery should be postponed, or alternative treatment should be considered. When surgery cannot be postponed for emergency reasons (e.g., imminent J o u r n a l P r e -p r o o f danger to life due to massive hemorrhage, severe infection, airway obstruction; malignant tumor; trauma including skin/mucosal laceration requiring suture, maxillary or mandible fracture, alveolar fracture, and tooth dislocation/fracture), surgery should be performed as an "inevitable choice" for as short operative duration as possible. Patients with untested results should be treated as patients with positive assessment results. Even if the assessment result is negative, as the number of infected individuals increases, the number of patients with negative assessment results who actually have the virus, in other words, "false negative" patients, increases, and the probability of encountering false-negative patients in daily clinical practice also increases. Thus, when surgery is not urgent but can be postponed, surgery should be postponed until community transmission subsides, or alternative treatment should be considered. Only surgeries that are highly needed should be performed. * Refer to figure: Surgical decision algorithm. When surgery is performed for patients with positive assessment results from a potential or epidemic zone, the surgeons and assistants should properly wear PPE with N95 respirators to prevent infection through aerosols and droplets. When surgery is performed for patients with untested results, surgeons and assistants, should properly wear PPE with N95 respirators to prevent infection through aerosols and droplets. However, when PPE with an N95 respirator is unavailable, simple PPE should be worn properly as an inevitable option. In such cases, the following conditions for the operating room environment should be implemented to perform surgery. When the assessment result is negative, surgeons and assistants should properly wear simple PPE to perform surgery. When surgery is performed for patients from a high community-transmission zone who have a positive assessment result or untested result, surgeons and assistants should properly wear PPE with N95 respirators to prevent infection through aerosols and droplets. As the number of infected individuals increases, the number of patients with negative assessment results who actually have the virus, in other words, "false negative" patients, increases, and the probability of encountering false-negative patients in daily clinical practice also increases. When surgery is performed for patients even with a negative assessment result, proper wearing of PPE with N95 respirators is preferable. When the N95 respirator is unavailable, performing surgery with proper wearing of simple PPE is acceptable. In such a case, the following conditions for the operating room environment should be implemented to perform surgery. Furthermore, to prevent infection, it is very important to properly wear and remove PPE, including N95 respirators, surgical masks, and other equipment. It is necessary for medical professionals to know how to wear and remove PPE by referring to 6. Appendix: Proper ways to wear and remove an N95 respirators and PPE or other references. If they are equipped with HEPA filters, the filters should be replaced periodically. After each performed surgical procedure, the operating room should be thoroughly ventilated to eliminate aerosols and droplets generated during surgery (refer to 6. Appendix: Indication of ventilation). Whenever surgery is performed, the operating table, the dental unit, and peripheral equipment should be sterilized, disinfected, or wiped (refer to 6. Appendix: Disinfection and cleaning of equipment). While preparing the operating room, attention should be paid to the transmissibility of waste materials. Those performing these tasks should wear a surgical mask, surgical gloves, face shield/goggles, long-sleeved gown, and surgical cap. Not particularly recommendable. In the assessment, views that were agreed on by ≥70% of the members were regarded as the views of the entire group. Voting was repeated until this level of agreement was obtained. The Working Group prepared the guide and algorithms for the performance of While there are many asymptomatic cases of COVID-19, the main symptoms include fever, physical weakness, cough, myalgia, and dyspnea. Characteristically, many patients complain of dysosmia and dysgeusia. In a telephone survey, 202 patients with COVID-19 were asked whether they noticed any abnormalities or changes in smell or taste perception, and they graded the abnormalities or changes into six grades. The A common chest computed tomography (CT) finding in patients with COVID-19 is ground glass opacity. Ground glass opacity is often observed in one area in patients aged <35 years and in multiple areas in those aged ≥60 years [2] . At first, patients develop symptoms such as cold, smell disorder, and taste disorder. In approximately 80% of patients, their symptoms remain mild and are cured in approximately one week after the onset. In approximately 20% of the patients, their symptoms of pneumonia are exacerbated by one week to 10 days after the onset, and hospitalization is necessary. Furthermore, from the tenth day after the onset, approximately 5% develop severe conditions requiring mechanical ventilation and other treatments, and 2% to 3% develop critical conditions [3] . As for the pathogenic mechanism, SARS-CoV-2 is known to use angiotensinconverting enzyme 2 (ACE2) to enter a cell. When SARS-CoV-2 infects humans, it first binds to the ACE2 receptor, a receptor present on the surface of a target cell. When the spike protein (S protein) of SARS-CoV-2 binds to the ACE2 receptor, the virus begins to enter the cell. The S protein needs to be cleaved by a protease present in the host cell, called transmembrane protease serine2 (TMPRSS2). ACE2 is usually involved in blood pressure regulation; therefore, the findings that have been reported include the following: SARS-CoV-2 may induce cardiovascular disorders by binding to ACE2 receptors; the kidney tubules, which highly express ACE2 receptors, are a high-risk organ for viral invasion, and cancer patients are likely to develop severe conditions [4] . With regard to the transmissibility of SARS-CoV-2, a study with artificially aerosolized SARS-CoV-2 showed that SARS-CoV-2 remained transmissible for up to 3 J o u r n a l P r e -p r o o f h in aerosols and 72 h on plastic and stainless steel [5] . When SARS-CoV-2 was cultured in viral transport media, the transmissible virus was almost stable for 2 weeks at 4℃ but became undetectable on the second day at 37 ℃, within 30 min at 56℃, and within 5 min at 70℃. With regard to the stability of SARS-CoV-2, its transmissibility was evaluated with a cultured virus that was applied to various environments (substances) in the form of a 5-μL drop and collected over time. The transmissible virus was undetectable on paper and tissue paper at 3 h after application; on wood and fabric by the second day; on glass and paper currency until the fourth day; and on plastic and stainless steel until the seventh day. On the external surface of a mask, the transmissible virus was detected even on the seventh day [6] . However, sufficient data on the transmissibility of the virus in the oral cavity or saliva of patients with COVID-19 or on the transmissibility and stability of the virus in aerosols generated in the oral cavity have not been accumulated. The results and data from future studies are awaited. Oral and maxillofacial surgery is a clinical field that treats congenital and acquired diseases occurring in the oral cavity, jaw, face, and adjacent tissues (refer to the home page of the Japanese Society of Oral and Maxillofacial Surgeons [https://www. jsoms.or.jp/]. This guide scopes all surgery associated with the treatment of oral and maxillofacial areas. The range of treatment varies widely, including tooth extraction, dental implant placement, incisional drainage of intraoral and extraoral abscesses, resection of jaw cysts, resection of oral cancer, jaw fracture surgery, maxillary and mandibular osteotomy, mandibular joint surgery, and cleft lip/cleft palate surgery. During the surgical procedures in oral and maxillofacial areas, surgeons and assistants may be exposed to SARS-CoV-2 through contact with the oral cavity, nasal J o u r n a l P r e -p r o o f cavity, or body fluid. Furthermore, those surgical procedures are performed with devices that may generate aerosols. For example, a dental high-speed turbine/micromotor handpiece used for extraction of impacted teeth; implanter (dental implant motor) used for dental implant placement; bone saw, bone drill, and ultrasonic bone scalpel used for osteotomy; electrocautery/laser used for incision of soft tissue and hemostasis in the surgery of tumors and other procedures. There are concerns that because aerosols generated by these devices are easily mixed with saliva, blood, or other fluids of patients, the resultant aerosols may contaminate the air and objects in the vicinity and increase the risk of nosocomial infection of COVID-19. As described above, the field of oral and maxillofacial surgery is exposed to greater risk of COVID-19 than other clinical fields. Therefore, appropriate risk management is essential. This guide is based on the SRs of academic articles that were conducted as of September 7, 2020 and have been prepared in consideration of information from related academic societies, the government, and media reports on the epidemic situation and the virus. Although we took all possible measures to ensure the accuracy of information available at the time of preparation of this guide, the Japanese Society of Oral and Maxillofacial Surgeons shall not be liable for any damages or disadvantages caused by the consideration/implementation of various measures based on this guide (including lost benefits and various expenses). Saliva contains transmissible SARS-CoV-2. Evidence level: D (very low) Recommended grade: Weakly recommended J o u r n a l P r e -p r o o f None of the 25 articles identified by the search strategy indicated that transmissible SARS-CoV-2 was detected in saliva. All accessed articles indicated that the nucleic acid of SARS-CoV-2 was amplified from saliva samples by PCR, instead of detection of transmissible virus [1] [2] [3] [4] [5] [6] [7] [8] [9] . All those articles reported a comparison of the positive rate and sensitivity of PCR test for the detection of nucleic acid of SARS-CoV-2 between saliva and nasopharyngeal swab samples. In addition, no study described in this SR met the requirements for an RCT. However, given that the PCR test for the detection of viral nucleic acids in nasopharyngeal swab samples is the standard test to confirm infection with SARS-CoV-2 even before the COVID-19 pandemic, those articles may provide indirect evidence that the viral load in saliva is comparable with that in a nasopharyngeal swab sample. In the report of a study conducted including 70 patients with confirmed COVID-19, the number of RNA copies (expressed as the logarithmic value) of SARS-CoV-2 was 5.58 in 1 mL of saliva collected by the patients themselves and 4.93 in nasopharyngeal swab samples. This study showed that the amount of SARS-CoV-2 contained in saliva might be comparable with or exceed the amount contained in nasopharyngeal swab samples [1] . Similarly, a study comparing the cycle threshold (Ct) values, which are derived from the number of PCR cycles, suggested that the amount of viral nucleic acid contained in saliva is comparable with that contained in nasopharyngeal swab samples [2] . On the other hand, among reports on PCR testing using nasopharyngeal swab samples, a study using cultured Vero E6 cells to detect transmissible SARS-CoV-2 showed that the detection rate of transmissible SARS-CoV-2 with a Ct value of >35 decreased to 8.3%. This suggests that a low Ct value corresponds to a large amount of transmissible SARS-CoV-2 [10] . When PCR test was performed with saliva samples, the Ct values were 25 to 30 in many cases [2] . This may indicate the presence of transmissible SARS-CoV-2 in saliva. In a study that included 103 Japanese patients with COVID-19 (88 symptomatic and 15 asymptomatic patients), 81.6% had positive PCR test using saliva samples [6] . In this study, an antigen test for SARS-CoV-2 was simultaneously performed with saliva samples and yielded a positive rate of 11.7%. Despite the low detection rate, detection of antigens may suggest the presence of viable virus in the saliva. The positive rates for PCR testing using saliva samples were 64% in asymptomatic patients and 81% in symptomatic patients, whereas the positive rates for PCR testing using nasopharyngeal swab samples were 62% in asymptomatic patients and 100% in symptomatic patients. While PCR testing using saliva samples is as sensitive as PCR testing using nasopharyngeal swab samples, the viral load in saliva is suggested to be higher in symptomatic patients than in asymptomatic patients [8] . In addition, when the PCR test was performed with supernatant from Vero cells dissolved by adding patient samples (urine, saliva, and feces), "transmissible" SARS-CoV-2 was detected in the saliva samples from two of five patients with COVID-19 [11] . Despite the small sample size, this study may have demonstrated the presence of transmissible SARS-CoV-2 in saliva. If SARS-CoV-2 exists in saliva, there is the question of which part of the oral cavity the virus is localized in. According to an article that was not selected during this search [12] , by immunostaining, it was demonstrated that the protein of ACE2 receptor, the receptor used by SARS-CoV-2 to bind to and invade the human cells, is expressed in human J o u r n a l P r e -p r o o f labial and submandibular glands. This suggests that SARS-CoV-2 is excreted in the saliva. Although this article indicated that ACE2 receptors were not expressed in the epithelial cells of the human lingual mucosa, another article [13] reported that genetic analysis showed expression of ACE2 receptor gene in the cells of the gingiva, buccal mucosa, and tongue. In summary, saliva may satisfy the conditions for accumulation of SARS-CoV-2. Database: PubMed There are few reports of direct studies on transmissibility, and direct assessment of transmissibility is a future issue. The accumulation of findings is so limited that selection bias and other bias risks cannot be avoided. No apparent inconsistency was found. None. infected patients without the concern of hospital-acquired infection? Until findings accumulate on the loss of transmissibility of SARS-CoV-2 in the oral cavity and the safety of oral and maxillofacial surgery, patients with history of COVID-19 or those with history of a positive PCR test result for SARS-CoV-2 should be treated as patients with COVID-19, regardless of the latest assessment result. Evidence level: D (very low) Recommended grade: Strongly recommended J o u r n a l P r e -p r o o f There are no articles that correspond to this CQ. Thus, the evidence level is D (low), and the effect estimate is almost unconvincing. The latent period of SARS-CoV-2 ranges from 1 to 14 days, and symptoms often appear approximately 5 days after exposure [1] . SARS-CoV-2 appears to proliferate in the upper and lower respiratory tracts. In severe cases, the viral load is high, and the viral shedding duration also tends to be long. Detection of pathogenic genes at 3 to 4 weeks after onset is not rare [2] . However, the detection of pathogenic genes is not synonymous with the presence of transmissible virus. The infectious period is assumed to be from 2 days before the onset to approximately 7-10 days after the onset (or before isolation in strict epidemiological studies) [2] . In fact, according to the "Guidelines for the Treatment of Coronavirus Real-time PCR or quantitative antigen test using nasopharyngeal swab samples is a useful method to determine whether patients are infected with COVID-19 before surgical procedures in oral and maxillofacial areas. Evidence level: B (moderate) Recommended grade: Strongly recommended J o u r n a l P r e -p r o o f When a patient is from an epidemic zone or may be infected with COVID-19, it is necessary to examine such before surgical procedures and treatment of oral and maxillofacial areas, whether they are infected with the virus. For symptomatic patients, it is recommended to perform nucleic acid detection tests or quantitative antigen tests with nasopharyngeal swab, nasal swab, or saliva samples [1] . However, when these tests are performed with saliva samples, attention should be paid to the low detection rate of these tests from 10 days after the onset. For asymptomatic patients, it is recommended to perform PCR test or quantitative antigen test with nasopharyngeal swab or saliva samples [1] . Nasal swabs are not recommended. The LAMP test is reported to yield false-positive results depending on the type of samples, such as saliva. Although saliva is an easy-to-use sample for the dentists and oral surgeons, the test results may be affected by eating, drinking, toothbrushing, and gargling. It is preferable to avoid the collection of saliva immediately after gargling. After eating, drinking, and toothbrushing, it is preferable to allow an interval of approximately 30 min before the collection of saliva, if possible [1] . Chest CT is used for the screening of COVID-19 because even asymptomatic patients with COVID-19 frequently present with characteristic findings. However, based on meta-analyses of patients with confirmed or suspected COVID-19, CT is reported to have a high sensitivity of 62% to ≥90%, but a low specificity of 25% to 46% [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] . Because of the high false-positive rate, CT is commonly viewed as unsuitable for the screening of infected patients. In addition, a study of asymptomatic hospitalized patients in a non-endemic area reported that both the sensitivity and positive predictive value were 0% [14] . Based on these results, screening with chest CT is not recommended, especially in non-endemic areas. Preoperative tests should preferably be performed at the shortest possible interval before surgery. Database: PubMed Refer to the Comment (section 4.3.3). Because there are no studies on patients undergoing surgical procedures in oral and maxillofacial areas, the issue of indirectness remains. The accumulation of findings is so limited that the risk of selective outcome reporting and other risks cannot be avoided. No apparent inconsistency was found. None. To reduce the risk of contracting COVID-19 for surgeons and assistants, patients should wash/rinse their mouth with povidone-iodine immediately before surgery. Evidence level: D (very low) Recommended grade: Weakly recommended At present, it is unknown to what extent povidone-iodine mouth wash/mouth rinse performed by patients immediately before surgery contributes to the prevention of viral transmission from patients with COVID-19 to surgeons and assistants. In the SR conducted by the subcommittee, no research articles providing direct answers were found. However, we decided to "weakly recommend" mouth wash/mouth rinse with povidone-iodine because it is easy and cheap, is associated with low risk, and may transiently reduce the viral load in saliva. We provide evidence for our decision as follows. It has been demonstrated that mouth wash/mouth rinse with an antimicrobial solution (e.g., chlorhexidine gluconate, essential oil-containing mouth wash/mouth rinse, or cetylpyridinium chloride) before dental treatment reduces the bacterial load in aerosols (note: not viral load) [1] . Aerosols generated during dental treatment contain oral bacteria, and these bacteria are reduced by mouth wash/mouth rinse with an antimicrobial solution before dental treatment. Thus, mouth wash/mouth rinse with an antiviral solution against SARS-CoV-2 in saliva may reduce aerosolized SARS-CoV-2. SARS-CoV-2, which has an envelope, is generally sensitive to disinfectants. Among disinfectants available as mouth wash/mouth rinse, povidone-iodine is the first-choice agent that is expected to have an antiviral effect. Povidone-iodine is a gargle that can be prescribed and has been widely used in Japan. Except for patients who are allergic to it, it appears to be safe to use for a "single application" such as preoperative mouth wash/mouth rinse. Multicenter in vitro studies have demonstrated the antiviral activity of povidoneiodine on SARS-CoV-2 [2] [3] [4] [5] . Although the concentration and duration of action of povidone-iodine varied among studies, the results showed that "SARS-CoV-2 was completely inactivated by the contact with 0.5% povidone-iodine for 15 seconds." Povidone-iodine is also expected to be clinically effective. In Japan, the concentration of povidone-iodine gargle solution that can be prescribed is 7%, and this solution is In addition to povidone-iodine, the US Centers for Disease Control and Prevention (CDC) guidelines [6] issued after the outbreak of COVID-19 recommend the use of J o u r n a l P r e -p r o o f chlorhexidine gluconate, essential oil, and cetylpyridinium chloride as mouth wash/mouth rinse before dental treatment, while the American Dental Association (ADA) guidelines [7] recommend povidone-iodine (0.2%) and hydrogen peroxide solution (1.5%). Although povidone-iodine is used in Japan, Hong Kong, Korea, Taiwan, Singapore, Malaysia, and the Philippines, among others, its use is not common in Europe and the United States. A possible reason why the US CDC [6] and ADA [7] ) guidelines recommended other drugs in addition to povidone-iodine is because povidone-iodine is not widely used. As with other disinfectants, the presence of contaminants including proteins, such as food residues, dental plaque, tongue coating, and blood, markedly weakens the antiseptic effect of povidone-iodine. Thus, cleansing of the oral cavity "before" mouth wash/mouth rinse is fundamental (refer to section 6. Appendix: Precautions for gargling) Furthermore, the "duration" of antiviral activity, which is clinically very important, is also unknown. The expression of ACE2 receptors, to which SARS-CoV-2 binds, has been confirmed in the duct of the salivary gland in addition to the tongue and gingival mucosa. Even if povidone-iodine is effective on SARS-CoV-2 in the saliva that is excreted in the oral cavity, its effect on saliva excreted after mouth wash/mouth rinse is unknown. In other words, its antiviral activity against SARS-CoV-2 in the saliva contained in the duct, is unknown. This issue needs to be investigated. A negative view of preoperative mouth wash/mouth rinse is that because SARS-CoV-2 exists not only in saliva but also rather abundantly in the nasal cavity and pharynx, mouth wash/mouth rinse alone is insufficient. There is another view that mouth wash/mouth rinse should be performed in combination with gargle or nasal lavage (so- Database: PubMed Because there are no studies on patients undergoing oral surgical procedures, the issue of indirectness remains. The accumulation of findings is so limited that the selection bias and other bias risks cannot be avoided. No apparent inconsistency was found. Appropriate PPE should be used to perform even simple incisions (e.g., biopsy) or tooth extraction with the use of forceps/an elevator. Evidence level: D (very low) Recommended grade: Strongly recommended There are currently no studies showing the extent of aerosol generation by each procedure, such as by simple incision (biopsy) or tooth extraction. Meanwhile, SARS-CoV-2 has been suggested to exist in the oral mucosal epithelium, salivary duct epithelium, and saliva [1] [2] [3] [4] [5] [6] [7] [8] . There are also reports of massive aerosol generation through conversation and speech [9] [10] [11] . Based on these reports, it cannot be ruled out that oral and maxillofacial surgeons, who perform therapeutic procedures near the oral cavity of patients, may be exposed to aerosols generated in the oral cavity of patients Despite the lack of articles corresponding to the CQ, we considered that the benefits of strict infection control in surgical procedures of oral and maxillofacial areas outweigh the economic burden on medical professionals. Thus, we regarded the recommended grade as strongly recommended. Database: PubMed The use of N95 respirators by operators and assistants in oral and maxillofacial surgery is effective for the prevention of infection with aerosolized SARS-CoV-2. Evidence level: C (low) Refer to the Comment (section 4.6.3). Because there are no studies on patients undergoing oral surgical procedures, the issue of indirectness remains. The accumulation of findings is so limited that the risk of selective outcome reporting and other risks cannot be avoided. No apparent inconsistency was found. None. Recommended grade: Weakly recommended Of the 37 articles selected for the second screening, one article [1] was included in the analysis. This article describes an experimental study on a simulation model using a dental mannequin that was conducted to evaluate the usefulness of extraoral vacuum and other techniques. The results showed that the combination of high-volume suction (intraoral suction) and extraoral vacuum reduced the contamination of the operative field with droplets. It also reduced the exposure of the surgeons and assistants to droplets (reducing the frequency of contamination of the operative field by 20% and the average contamination intensity by 75%). This study suggested that the combination of intraoral and extraoral suction might be effective for reducing the risk of contracting COVID-19 [1] . An article not selected at the second screening indicates that aerosols are contaminated by blood from the oral cavity of patients, in the real-world setting. This also suggests the usefulness of extraoral vacuum [2] . Because this recommendation is based on an exploratory study reported by a single group, the evidence level is D (very low). Database: PubMed Refer to the Comment (section 4.7.3). Because there are no studies on patients undergoing oral surgical procedures, the issue of indirectness remains. The accumulation of findings is so limited that bias risks, such as the selection and J o u r n a l P r e -p r o o f performance biases, cannot be avoided. No apparent inconsistency was found. None. When the contents of the guide need to be changed in consideration of the extent of spread of infection, data issued by the government, current status of medical care, and new findings from articles published in journals or presented at academic conferences, will be used by the subcommittee to revise the guide as necessary. 6. Appendix When povidone-iodine or other disinfectants are used for gargling, attention should be paid to the appropriate concentration and duration of action of disinfectants, and also to possible contaminants. The presence of many contaminants, mainly proteins, in the oral cavity markedly weakens the effect of disinfectants. When gargling is performed in two sessions (first session with 5 cc of solution for 10 seconds and the second session with 15 cc for 20 seconds), contaminants are neutralized and diluted in the first session "with 5 cc for 10 seconds". Gargling in this manner is far more effective than gargling "in one session with 20 cc for 30 seconds". It is preferable, but not essential, to use negative-air-pressure for the examination rooms, and inpatient wards that are used for patients with COVID-19 (including suspected cases). Rooms with adequate ventilation are sufficient. It is recommended to check the ventilation conditions (e.g., ventilation frequency) in facilities before use. If The following information on cases suitable for the use of disinfectants for SARS-J o u r n a l P r e -p r o o f mucosal surfaces. Although isopropanol (70%) may be used as an alcohol-based disinfectant, its antiviral effect is inferior to that of ethanol. Quick-drying skin disinfectants (e.g., brand names: Welpas and Hibiscol; ingredients: benzalkonium chloride or chlorhexidine gluconate, ethanol, surfactants, and humectants) are frequently used for hand disinfection. When blood and other substances contaminate the skin, the disinfectants may not reach the skin surface. The hands and fingers should be washed, because alcohol-based disinfectants are flammable; therefore, their use requires caution, and they are unsuitable for spraying over a wide area. In addition, their use is regulated by the Fire Service Act. (3) Peracetic acid: It is effective at a low concentration (0.001%-0.2%) against all microorganisms, including spores. It is even effective in the presence of organic compounds. It is eventually degraded to water, oxygen, and acetic acid, but has no hazardous remnant. Peracetic acid corrodes some metals and has an irritating smell. Heniford BT A systematic review of CT chest in COVID-19 diagnosis and its potential application in a surgical setting Collaborators of the European Society of Paediatric Radiology Cardiothoracic Imaging Taskforce Coronavirus disease 2019 (COVID-19) in children: a systematic review of imaging findings Hope MD The Limited Sensitivity of Chest Computed Tomography Relative to Reverse Transcription Polymerase Chain Reaction for Severe Acute Respiratory Syndrome Coronavirus-2 Infection: A Systematic Review on COVID-19 Kwee RM Systematic Review and Meta-Analysis on the Value of Chest CT in the Diagnosis of Coronavirus Disease (COVID-19): Sol Scientiae, Illustra Nos Chest CT for detecting COVID-19: a systematic review and meta-analysis of diagnostic accuracy Yoon SH Diagnostic Performance of CT and Reverse Transcriptase Polymerase Chain Reaction for Coronavirus Disease 2019: A Meta-Analysis Radiology Atallah ÁN Reverse-transcriptase polymerase chain reaction versus chest computed tomography for detecting early symptoms of COVID-19 Pannuti CM Efficacy of preprocedural mouthrinses in the reduction of microorganisms in aerosol: A systematic review Tessema B Rapid In-Vitro Inactivation of Severe Acute Respiratory Syndrome Coronavirus Using Povidone-Iodine Oral Antiseptic Rinse J Prosthodont Tessema B Comparison of In Vitro Inactivation of SARS CoV-2 with Hydrogen Peroxide and Povidone-Iodine Oral Antiseptic Rinses Povidone-Iodine Demonstrates Rapid In Vitro Virucidal Activity Against SARS-CoV-2, The Virus Causing COVID-19 Disease Infect Dis Ther Capriotti JA Efficacy of Povidone-Iodine Nasal and Oral Antiseptic Preparations Against Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) The Centers for Disease Control and Prevention. Interim Infection Prevention and Control Guidance for Dental Settings During the COVID-19 Response ADA Interim Guidance for Minimizing Risk of COVID-19 Transmission. f (DUWL) OR dentistry OR oral OR maxillofacial)) ) Systematic review: No SR was conducted because of the lack of articles identified by the second screening A prospective clinical pilot study on the effects of a hydrogen peroxide mouthrinse on the intraoral viral load of SARS-CoV-2 Shamsoddin E Saliva: a diagnostic option and a transmission route for 2019-nCoV Evid Based Dent Schwendicke F Saliva is a potential source of Covid-19, and appropriate protection measures should be applied in dental practice Evid Based Dent the COVID-19 Outbreak Diagnostics (Basel) Saliva is a non-negligible factor in the spread of COVID-19 Saritha M A Review of Salivary Diagnostics and Its Potential Implication in Detection of Covid-19 Cureus Saliva: potential diagnostic value and transmission of 2019-nCoV Epithelial cells lining salivary gland ducts are early target cells of severe acute respiratory syndrome coronavirus infection in the upper respiratory tracts of rhesus macaques Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis The need of health policy perspective to protect Healthcare Workers during COVID-19 pandemic. A GRADE rapid review on the N95 respirators effectiveness CDC-related home page: Strategies for Optimizing the Supply of N95 Respirators Administrative notice issued by the Japanese Ministry of Health, Labor and Welfare on April 10, 2020: Exceptional use of masks To reduce the risk of COVID-19 transmission, the combination of intraoral suction and extraoral vacuum is recommended CoV-2 is posted on the home page of the Infectious Disease Surveillance Center of the National Institute of Infectious Diseases. The use of disinfectants for SARS High-pressure steam (autoclave) sterilization (121℃ for 20 min) Dry heat sterilization (180-200℃ for 1 h or 160-170℃ for 2 h) Sodium hypochlorite: Although it is commonly used for sterilization by immersion in a solution with an effective chlorine concentration of 0 Sodium hypochlorite is corrosive to fabric and metal, and is less effective when organic compounds are attached. It cannot be used on the human body. Linens should be soaked in a 0.1% solution (1,000 ppm) for 30 min and then washed with water. Dishes and other utensils should be soaked in a 0.01% to 0.02% solution (100-200 ppm) for ≥5 min after they are washed with water. For the disinfection of excrement Ethanol is less toxic to the human body and suitable for disinfection of the hands and fingers. Unless it is stored in an airtight container, the alcohol content may evaporate. Thus, the alcohol concentration decreases; therefore, the ethanol dramatically loses its effect. The alcohol may cause degreasing Formaldehyde (liquid: immersion in a 1%-5% solution; gas: spraying or humidifying with formaldehyde at ≥15 mL/m 3 along with ≥40 mL of water for The formaldehyde solution is used for disinfection of medical devices by immersion or wiping. Although formaldehyde can be gasified to be used for disinfection of rooms, its gaseous form is very toxic and irritating Ethylene oxide gas: It is applied at a concentration of approximately 500 mg/L at 55-60℃ for ≥3 h. It is used to sterilize heat-labile devices in the central supply room. Caution should be exercised to ensure the absence of residual gas after sterilization. Inhalation of the gas causes airway inflammation, nausea, dizziness, and neurological symptoms When Iodophor becomes alkaline, it is ineffective. Iodophor becomes less effective when mixed with organic compounds; or when there is sputum or blood. Iodophor is corrosive to common metals and stains the skin, mucosa, and fabric. A 10% solution is used for skin disinfection of the surgical site. A 7.5% scrub solution is used for disinfecting the hands, fingers, and skin. A 10% gel is used for disinfection of wounds. To use for gargling, a 7% solution is diluted according to the instructions in the package insert. High-concentration iodine-based disinfectants are irritating to the skin and may cause iodine hypersensitivity. (8) Benzalkonium chloride, chlorhexidine, and surfactants may also have antiseptic properties, but their effects may be inadequate. Thus, at present, the methods of disinfection described above (1. Items suitable for heat sterilization and 2. Items unsuitable for heat sterilization), are recommended for disinfection of SARS-CoV-2.