Updated: February 26, 2021

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


The following is a short summary of the available evidence on the infection prevention and control guidance for dental procedures that potentially involve aerosol transmission of SARS-CoV-2. Three systematic reviews, one rapid review, five guidance documents, one literature review and one single study were found to answer this question and were used in this REAL Summary. For additional information about each of the sources, see the Table below.

The authors of two reviews, and guidance from the Royal College of Dental Surgeons of Ontario agree 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 (approx. 2 meters) and remain infectious in the air for 3-4 hours [1,2,6]. One State of Washington study (November 2020) found that based on 26,799 laboratory-confirmed cases as of June 16, 2020, the 15 occupations with the overall highest predicted risk of a COVID-19 infection were all healthcare professions, with four of the top five in the dental health field [9]. The COVID-19 Transmission in Dental Practice: Brief Review of Preventive Measures in Italy (April 2020) found 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 patient in the dental chair; and 4) the levels of microorganisms in the patient’s mouth [3].  
The following recommendations are outlined for dental settings 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 (December 2020), and in the updated guidance by the Royal College of Dental Surgeons of Ontario, COVID-19: Managing Infection Risks During In-Person Dental Care (January 2021): 1) use an N95 respirator (fit-tested and seal-checked), gloves, eye protection and/or a face shield and a 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) avoid the use of ultrasonic scalers is also not recommended [5,6]. If aerosol-generating procedures are necessary, it is recommended by the CDC (December 2020) and by Public Health Ontario (November 2020) 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 [1,4,5]. In the Public Health Ontario Guidance (July, 2020), it states that certain dental procedures are associated with significant aerosol generation including ultrasonic and sonic scalers, high-speed dental handpieces, air polishers and air-water syringes [8]. Therefore, a waiting period of 15-30 minutes between patients would allow for aerosols that may pose a risk of COVID-19 infection to settle [8]. The Dental Risks and Precautions during COVID-19 Pandemic: A Systematic Review (August 2020) state 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]. This systematic review also recommends that surfaces should be cleaned with 62-71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite or ultraviolet treatment after each patient visit [1]
The College of Dental Hygienists of Ontario (September 2020) and Office of the Chief Dental Officer of Canada (November 2020) guidance recommends that dental hygienists in the client treatment room should use N-95 masks, isolation gowns, gloves and eye protection (goggles or face shield), especially when aerosol-generating procedures cannot be avoided [10,11]. Implementation of a system to allow more time between patients (fallow time) between clients should be considered to reduce the risk of aerosol transmission [10,11]
In addition to patient procedures, the CDC recommends in the above report? 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]. A review (August 2020) advises that since SARS-CoV-2 is susceptible to oxidative agents, pre-treatment mouth washes containing 0.1% hydrogen peroxide, or 0.2% povidone might reduce viral salivary load [7]. In contrast, in the Public Health Ontario’s review (November 2020), it states that hydrogen peroxide should no longer be recommended due to its lack of efficacy against SARS-CoV-2 [4]. The CDC recommends that dentists should: 1) 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 [5]. Patients that request/require dental care should be screened prior to a dental examination such that a procedure can be deferred if COVID-19 is suspected [6]. Lastly, physical distancing is advised by limiting the number of visitors in the facility (e.g., video-call consults, minimizing overlapping appointments, and having patients wait in a personal vehicle or outside prior to their appointment) [5].  


What‘s Trending on Social Media and Media

Some Winnipeggers are questioning if they should keep their dental appointments out of fear that they contract COVID-19. The Manitoba Dental Association advises against postponing appointments, emphasizing they have additional safety measures in place to ensure everyone’s safety. The association said if you’re not feeling well on the day of your appointment, you should reschedule for another day. Access the full Global News article here (January 2021). 

Organizational Scan

In a webpage titled “COVID-19: What to Expect at the Dental Office” (January 2021), the Ontario Dental Association lists for patients the precautions that will be taken by dental staff and offices to prevent the spread of COVID-19. They also answer a series of frequently asked questions regarding the safety of dental visits, how to deal with a dental emergency and how to know if you are infected with COVID-19.  
The Ontario Dental Association guidance, updated on January 14, 2021, lists all 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 both prior to their appointments and upon arrival 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 [12]

Review of Evidence

Resource Type/Source of Evidence Last Updated
Dental Risks and Precautions during COVID-19 Pandemic: A Systematic Review
— Turkistani and Turkistani
Systematic Review
  • Methods: A comprehensive search of MEDLINE, Cochrane library, Google Scholar and ScienceDirect databases was completed March 19th, 2020 to include all articles discussing dental considerations during the COVID-19 outbreak. 
  • Using high-speed handpiece, ultrasonic scaler and three-way syringe generates aerosol from patient’s saliva. 
  • Preprocedural mouth rinse is one of the most effective methods of reducing proportion of microorganisms in oral aerosols and rubber dams provide barrier protection from pathogens that emerge from respiratory secretion during aerosol-generating dental procedures. 
  • Manual scaling is preferred over ultrasonic instrument. 
  • HVE and HEPA filters should be considered for filtering 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 or ultraviolet treatment. 
Last Updated: August 20, 2020
Protection and disinfection policies against SARS-CoV-2 (COVID-19)
— Fathizadeh et al.
Systematic Review
  • Methods: collected and summarized evidence on SARS-CoV-2 virus stability outside of the body, in air and on surfaces, to prevent further spread. 
  • The COVID-19 virus can survive in the air for 3 hours. 
  • 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
  • Methods: A literature search was conducted to retrieve articles relevant to COVID-19 and clinical dentistry with no strict inclusion criteria. Data they presented focused on the documented clinical experience, the professional prevention measures described, and the actual Italian situation to manage spread of COVID-19 in dental settings.  
  • The risk of COVID-19 inhalation transmission is extremely high during dental practice 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 will vary. 
Last Updated: April 16, 2020
Open operatory dental setting infection control practices and risk of transmission during aerosol-generating dental procedures
— Public Health Ontario
Rapid Review
  • Methods: Conducted a literature search in MEDLINE, SCOPUS and preprint databases for primary articles and reviews published between January 1 and November 3, 2020. Articles that provided experimental or clinical evidence were included, as were reviews that contained unpublished data on SARS-CoV-2 transmission from dental settings. 
  • Due to the lack of efficacy against SARS-CoV-2, hydrogen peroxide should no longer be recommended as a pre-operative mouth rinse.  
  • Pathogen non-specific contamination studies indicate that dental dams and suction play an important role in reducing aerosol spread during aerosol-generating dental procedures.  
  • Spread of SARS-CoV-2 may be impacted by air flow conditions and work practice controls but requires further research. 
Last Updated: November 25, 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 any non-urgent procedures be postponed and implement tele-dentistry whenever possible. 
  • Aerosol generating procedures should be avoided, but if necessary, fourhanded dentistry, high evacuation suction and dental dams should be used to reduce aerosols. 
  • During procedures, dental personnel should wear surgical masks, eye protection, a gown, and gloves. 
  • When providing care for a patient with suspected or confirmed COVID-19 infection, it is recommended that no other patients be scheduled at the same time and that the dental healthcare personnel wear an N-95 or equivalent high-level respirator. 
Last Updated: December 3, 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, face shield and a protective gown. 
  • Patients should also wear a protective gown during procedures. 
Last Updated: January 13, 2021
COVID-19 Pandemic: Dental Considerations and Review of Literature
— Patil et al.
Literature Review
  • This literature review outlines potential modes of transmission of SARS-CoV-2 in a dental setting either indirectly or directly - airborne and contaminated surface transmission is noted to be of most concern. 
  • The risk of transmission can be reduced by screening potential patients, practising hand hygiene, using personal protective equipment, providing mouth rinses and administering rubber dam isolations. 
Last Updated: August 1, 2020
COVID-19 in Dental Care Settings
— Public Health Ontario
Provincial Guidance
  • Certain dental procedures are associated with significant aerosol generation including ultrasonic and sonic scalers, high-speed dental handpieces, air polishers and air-water syringes.  
  • A waiting period of 15-30 minutes between patients would allow for aerosols that may pose a risk of infection to settle.  
Last Updated: July 7, 2020
Estimation of differential occupational risk of COVID-19 by comparing risk factors with case data by occupational group
— Michael Zhang
Single Study
  • Methods: Screened the Occupational Information Network (O*NET) database for potential predictors of COVID-19 infection risk by occupation. Obtained case counts by occupation from public data sources, and then correlated prevalence with O*NET data to predict occupations at greatest risk. 
  • Based on 26,799 laboratory-confirmed cases as of June 16, 2020 in the State of Washington, the study found that the 15 occupations which overall have the highest predicted risk are all healthcare professions, with four of the top five in the dental health field. 
  • The top five professions were: 1) Dental hygienists; 2) Oral and maxillofacial surgeons; 3) Dental assistants; 4) Dentists, general; and 5) Orderlies. 
Last Updated: November 7, 2020
Guidance on Returning to Dental Hygiene Practice
— College of Dental Hygienists of Ontario
Provincial Guidance
  • Recommend clients to use a pre-procedural rinse to reduce the salivary load of oral microbes. 
  • Where aerosol-generating procedures (e.g. use of A/W syringe, ultrasonic or powered scalers, high- or slow-speed handpieces, etc.) cannot be avoided, use appropriate PPE (i.e. N95 mask). 
  • Implement appropriate fallow time (fallow time begins once the client and clinician leave the room and the door is closed) even between clients from the same household. 
  • For dental hygienists in the client treatment room, the following PPE are recommended: N-95 mask, isolation gown, gloves, eye protection (goggles or face shield). 
Last Updated: September 2, 2020
Evidence to support safe return to clinical practice by oral health professionals in Canada during the COVID-19 pandemic: A report prepared for the Office of the Chief Dental Officer of Canada
— Office of the Chief Dental Officer of Canada
National Guidance
  • Evidence suggests that using a combination of PPE (face shield & N95 mask) is better than a single intervention.  
  • Recommended protocol for patient admission: 1) Pre-dental treatment: patient triage for COVID-19; 2) During dental treatment: hand hygiene, anti-microbial mouth rinse; 3) Post-dental treatment: Cleaning and disinfecting PPE. 
Last Updated: November 29, 2020
COVID-19: What to Expect When Your Dentist’s Office Reopens
— Ontario Dental Association
Organizational Scan Last Updated: January 13, 2021
COVID-19: Managing Infection Risk During In-Person Dental Care
— Royal College of Dental Surgeons of Ontario
Organizational Scan Last Updated: January 13, 2021
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.