Do measures that aim to reduce aerosol production during dental procedures prevent the transmission of infectious diseases?

Most dental care procedures create tiny drops of liquid that float in the air, called aerosols. For example, to remove the plaque that builds up on teeth, dentists use scalers. Scalers vibrate at high speed and use a flow of water to wash away the plaque. This produces aerosols that are made of air, water, and the patient’s saliva, which may also contain micro‐organisms such as bacteria, fungi and viruses. Aerosols that contain bacteria, fungi or viruses can spread infectious diseases. Limiting the production of these aerosols could help to prevent disease transmission in a dental setting, which is especially important at the moment because of the COVID-19 pandemic.

Methods of reducing aerosols include:

ways to prevent aerosols from leaving the mouth (for example, placing a rubber sheet – known as a ‘dam’ – around the tooth that is to be treated, to isolate the treatment zone from saliva; or using a straw‐like suction tube known as a saliva ejector);local ventilation using a suction device (known as a high‐volume evacuator) that draws up a large volume of air and evacuates aerosols from the treatment zone;general ventilation, to reduce the concentration of aerosols in the air, for example by keeping windows open;decontamination of air‐borne aerosols, for example using ultraviolet light to sterilize the air.

These can be used alone, or in combination.

What was the research?

A systematic review to examine whether interventions that aim to reduce aerosol production during dental procedures can prevent the transmission of infectious diseases. We also wanted to find out about the cost of the interventions, whether patients and dentists found them acceptable, and whether the interventions were easy to implement.

Who conducted the research?

The research was conducted by a team led by Sumanth Kumbargere Nagraj of Melaka-Manipal Medical College, Manipal Academy of Higher Education (MAHE), Melaka, Malaysia on behalf of Cochrane Oral Health. Prashanti Eachempati, Martha Paisi, Mona Nasser, Gowri Sivaramakrishnan and Jos H Verbeek were also on the team.

What evidence was included in the review?

We included 16 studies, including 425 participants. Studies involved between one and 80 participants, who were aged between 5 and 69 years. Six studies were conducted in the USA, five in India, two in the UK and one each in Egypt, the Netherlands and the United Arab Emirates.

What did the evidence say?

All 16 studies measured changes in the levels of bacterial contamination in aerosols, but we assessed the evidence as being of very low certainty. This means that we have very little confidence in the evidence, and that we expect further research to change the findings of our review. We therefore cannot deduce from this evidence whether there is an effect on levels of bacterial contamination. No studies investigated viral or fungal contamination.

None of the studies evaluated the risk infectious disease transmission. Nor did they evaluate cost, acceptability or ease of implementation.

What are the implications for dentists and the general public?

We do not know whether interventions that aim to reduce aerosol production during dental procedures prevent the transmission of infectious diseases. This review highlights the need for more and better‐quality studies in this area.

What should researchers look at in the future?

Further research should be undertaken to determine the most effective methods to reduce contaminated aerosols generated during dental procedures by conducting well‐planned randomised controlled trials (RCTs).


Kumbargere Nagraj  S, Eachempati  P, Paisi  M, Nasser  M, Sivaramakrishnan  G, Verbeek  JH. Interventions to reduce contaminated aerosols produced during dental procedures for preventing infectious diseases. Cochrane Database of Systematic Reviews 2020, Issue 10. Art. No.: CD013686. DOI: 10.1002/14651858.CD013686.pub2.

This post is an extended version of the review’s plain language summary, compiled by Anne Littlewood at the Cochrane Oral Health Editorial Base.

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