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Updated: June 15, 2020

What infection prevention and control guidance exists for dental procedures that potentially involve aerosol transmission of COVID-19?

Summary

The following is a summary of evidence sources that provide high quality information on the infection prevention and control guidance for dental procedures that potentially involve aerosol transmission of SARS-CoV-2. For additional information about each of the sources, see the Table below.

The authors of two reviews, two single studies and the Royal College of Dental Surgeons of Ontario report note that contamination from spatter and aerosolization from potentially infectious dental patients remains a significant hazard for dental personnel, as aerosols containing SARS-CoV-2 can travel more than six feet and remain infectious in the air for 3-4 hours [1,2,5,7,8]. As noted in [1], there is a risk of aerosol transmission, but there have been no reported cases of COVID-19 transmission in the dental setting. The authors of one review and two single studies found that some viruses remain present in saliva for 29 days after recovery and the virus-containing aerosols may persist of some surfaces for days [1,6,7]. It was found by one review and one single study that the distribution of contaminated aerosols and spatter during dental procedures may vary by: 1) the type of procedure and whether high-volume evacuation as used; 2) the position of the operator relative to the patient; 3) the position of the subject in the dental chair; and 4) the levels of microorganisms in the patient’s mouth [3,8].

The following recommendations are outlined by the Centers for Disease Control and Prevention (CDC) in its Interim Infection Prevention and Control Guidance for Dental Settings During the COVID-19 Response, and by the Royal College of Dental Surgeons of Ontario in its COVID-19: Managing Infection Risks During In-Person Dental Care: 1) use an N95 respirator (fit-tested and seal-checked), gloves, eye protection and/or a face shield and an optional protective gown when performing aerosol generating procedures; 2) avoid aerosol-generating procedures whenever possible; 3) avoid the use of dental handpieces and the air/water syringe; and 4) the use of ultrasonic scalers is not recommended [4,5]. If aerosol-generating procedures are necessary, it is recommended by the CDC to use: 1) four-handed dentistry (when a dentist and dental assistant work on a procedure together); 2) high evacuation suction; and 3) a dental dam to minimize droplet spatter and aerosols [4]. In the review on Possible aerosol transmission of COVID-19 and special precautions in dentistry, it states that a preprocedural mouth rinse is effective in reducing the proportion of microorganisms in oral aerosols and that high velocity evacuation (HVE) and high efficiency particulate air (HEPA) filters should be considered in filtering and removing contaminated air in treatment areas [1]. In the emergency treatment of suspected or confirmed COVID-19 cases, this review further recommends that: 1) the highest level of personal protective equipment (PPE) should be used; 2) a negative pressure room with a minimum of 12 air changes per hour is recommended; and 3) that mechanical ventilation should be started before the next patient enters the room [1].

In addition to patient procedures, the CDC recommends that high-touch surfaces (e.g. doorknobs, plexiglass barriers, handrails, counters and arms of chairs) in the dental offices should be disinfected at least twice a day and that procedure rooms should be cleaned and disinfected between each patient [4]. One review suggests that surfaces should be disinfected with 62-71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite to inactivate the virus within one minute [1]. The CDC recommends that: 1) dentists post visual alerts (e.g., signs, posters) within the office space to direct patients; 2) provide supplies for respiratory hygiene and instruction for cough etiquette (such as signage to cover your cough and wash hands); and 3) install physical barriers wherever possible to eliminate the spread of aerosol transmission.

Evidence

What‘s Trending on Social Media and Media

As dental clinics slowly start to re-open, dentists across the country have begun to plan and design alternative patient flows to ensure that patient safety is the top priority. With a shortage of PPE and the need to maintain social distancing, many dentists have cut-back on certain procedures that require in-person attendance by doing pre-screenings on the phone. Dentists foresee that tele-dentistry is likely to continue after the pandemic, and note that the dental industry will have a new reliance on digital technology. Access the full Global News article here.

In the United States, as reopening plans are gradually unfolding, dental practices are looking into adopting ultraviolet (UV) light technology to clean their facilities and equipment., a method that is widely used in hospitals. There is currently not enough data available to support the effectiveness of using UV light products against inactivating SARS-CoV-2 and the American Dental Association recommends it should only be considered in addition to standard hygiene practices. UV sanitizing products can include disinfecting towers for rooms, chambers for sterilizing equipment and air purifiers. Considerations include cost of implementation and ensuring precautions when handling the equipment. 

Organizational Scan

The Ontario Dental Association lists all the precautions to be taken by dentists and staff in dental offices to ensure that their patients and staff are protected. Some precautions include spacing out appointments, consulting with patients prior to their appointments regarding COVID-19 symptoms, the use of appropriate PPE by staff (i.e., masks, face shields and gowns), requesting patients to wash their hands with 70-90% alcohol-based solution and paying with touchless payment. The website also includes a patient protocol for dental emergencies, medical prescriptions and self-assessment of COVID-19 [9].

The Royal College of Dental Surgeons of Ontario website has highlighted the most recent Directive from the Chief Medical Officer of Health of Ontario. In the Directive, it states dentists can now start providing non-essential and elective care along with essential services, emergency and urgent care. The College ensures all dentists providing treatment follow Infection Prevention and Control Guidelines, which include the cleaning and disinfecting of office space and operatories between each patient appointment, the removal of non-essential items (e.g., toys, magazines) from office/reception areas, and frequent hand washing, especially before and after contact with patients, high-touched surfaces, or when removing PPE [10].

The Alberta Dental Association and College has released the Guidelines for Stage 1: Alberta Relaunch for Dental Practice to provide guidance for dental professionals and education for patients. The document lists measures that should be taken to minimize the risk from aerosol generating procedures such as using high volume suction to limit aerosols, proper donning and doffing of PPE, etc. The minimum level of PPE required for operatory versus reception settings in dental offices is based on staff/patients and the procedure. Lastly, the College provides a sample patient screening form along with a dental office relaunch checklist that could be utilized by dentists [11].

Review of Evidence

Resource Type/Source of Evidence Last Updated
Possible aerosol transmission of COVID-19 and special precautions in dentistry
— Zi-yu et al.
Systematic Review

This review notes that aerosols from pathogens like SARS-CoV-2 can travel more than six feet. Some virus strains can be present in saliva for as long as 29 days. For emergency treatment of suspected/ confirmed COVID-19 cases, highest level personal protective equipment (PPE) is required, a negative pressure room with a minimum of 12 air changes per hour should be used and mechanical ventilation should be commenced before the next patient. Preprocedural mouth rinse is one of the most effective methods or reducing proportion of microorganisms in oral aerosols. Rubber dams provide barrier protection from pathogens that emerge from respiratory secretion during aerosol-generating dental procedures. HVE and HEPA filters should be considered in filtering and removing contaminated air in treatment areas. After each patient visit, surfaces should be cleaned with 62-71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite.

Last Updated: March 2, 2020
Protection and disinfection policies against SARS-CoV-2 (COVID-19)
— Fathizadeh et al.
Systematic Review

This review states that SARS-CoV-2 spreads mostly through respiratory droplets and then through contaminated surfaces. The COVID-19 virus can survive in the air for 3 hours.

This review notes that common disinfectants eliminate the risk of spread and contamination of SARS-CoV-2. Cleaning and disinfecting repeatedly touched surfaces with 60% alcohol will inactivate the virus.

Last Updated: May 31, 2020
COVID-19 Transmission in Dental Practice: Brief Review of Prevention Measures in Italy
— Izzetti et al.
Rapid Review

This review suggests that the risk of COVID-19 inhalation transmission is extremely high during due to the use of handpieces under irrigation, which favors the diffusion of aerosol particles of saliva, blood, and secretions. Depending on the office set up, the contamination duration for harmful virus droplets vary.

Last Updated: April 16, 2020
Interim Infection Prevention and Control Guidance for Dental Settings During the COVID-19 Response
— CDC: Centers for Disease Control and Prevention
National Guidance

The CDC recommends that dentists ensure general office housekeeping, including cleaning and disinfection of high-touch surfaces, occurs at least twice per day (e.g., doorknobs, plexiglass barriers, handrails, counters, and the arms of chairs). It is mandatory that dental examination or procedure rooms/areas (also known as operatories) must be cleaned and disinfected between each patient appointment. It is recommended that dentists post visual alerts (e.g., signs, posters), provide supplies for respiratory hygiene and cough etiquette and install physical barriers wherever they can to eliminate the spread of aerosol transmission. The CDC recommends: 1) avoiding aerosol-generating procedures whenever possible; 2) avoiding the use of dental handpieces and the air/water syringe; and 3) the use of ultrasonic scalers is not recommended. If aerosol-generating procedures are necessary for dental care use: 1) four-handed dentistry; 2) high evacuation suction; and 3) a dental dam to minimize droplet spatter and aerosols.

Last Updated: May 2, 2020
COVID-19: Managing Infection Risks During In-Person Dental Care
— Royal College of Dental Surgeons of Ontario
Professional Organization

The Royal College of Dental Surgeons of Ontario suggests that that the transmission of the virus may persist as aerosols for 3-4 hours, and on some surfaces for days under laboratory conditions, despite sanitization. During any aerosol generating procedures everyone must wear an N95 respirator (fit-tested, seal-checked), or the equivalent, as approved by Health Canada, gloves for COVID-19, eye protection and/or face shield and an optional protective gown.

Last Updated: May 30, 2020
Guidelines for dental care provision during the COVID-19 pandemic
— Alharbi et al.
Single Study

This study states that to date, no universal protocol or guideline is available for dental care provision for active or suspected COVID-19 cases. Some viruses can be present in saliva for as long as 29 days after the recovery of the patient. This study suggests that dental offices use proper aerosol-generating procedures PPE for every procedure.

Last Updated: April 6, 2020
Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1
— van Doremalen et al.
Single Study

This study notes that aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can remain viable and infectious in aerosols for 3-4 hours and on surfaces up to days.

Last Updated: March 16, 2020
Evaluating Spatter And Aerosol Contamination During Dental Procedures
— Bentely et al.
Single Study

This study describes that contamination from spatter and aerosol dissemination remains a significant hazard for dental personnel. The distribution of contaminated aerosols and spatter varied by: 1) the type of procedure and whether high-volume evacuation was used; 2) the position of the tooth in the mouth, which affects the position of the operator relative to the subject; 3) the position of the subject in the dental chair; and 4) levels of the microorganisms in the subject’s mouth.

Last Updated: April 30, 1994
COVID-19: What to Expect When Your Dentist’s Office Reopens
— Ontario Dental Association
Organizational Scan Last Updated: May 31, 2020
Patient dental treatment during the COVID-19 pandemic
— Royal College of Dental Surgeons of Ontario
Organizational Scan Last Updated: June 8, 2020
Expectations and Pathway for Patient Care during the COVID-19 Pandemic
— Alberta Dental Association and College
Organizational Scan Last Updated: May 27, 2020
Disclaimer: The summaries provided are distillations of reviews that have synthesized many individual studies. As such, summarized information may not always be applicable to every context. Each piece of evidence is hyperlinked to the original source.

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