Changes to Drills can Reduce the Spread of COVID-19 in Dental Practices

Dentists can further reduce the potential spread of COVID-19 in their practices by adjusting one tool: dental drills. A recent study found that changing how dentists use drills can limit the spread of aerosol particles in a room — hugely significant in the age of coronavirus.

Aerosols are a known transmission route of the virus. In fact, just one milliliter of saliva from a COVID-19-infected person contains 120 million copies of the virus, each of which can cause infection. Dentistry is considered to be a high-risk profession during COVID-19 because of the dental staffs’ inherent close contact with patients’ mouths and saliva.

Researchers at Imperial College London and King’s College London studied aerosol generation in dental practices to find better alternatives, the results of which were published in a paper in the Journal of Dental Research. The researchers measured aerosols using cameras and lasers during procedures such as decay removal, applying and polishing finishes and adjusting prostheses.

The researchers recommend two adjustments to dental drills to make a big difference to aerosol production.

1. Using just water coolants in the drills, rather than a mixture of water and air, limits the saliva that enters the air.
2. Using drills at lower speeds also creates less disruption of saliva particles that then become aerosolized.

The researchers found that, together, those changes allow a dentist to perform a procedure while producing 60 times fewer aerosol droplets.

The most common drill is an air turbine type which creates dense clouds of droplets that can quickly contaminate a room. When using a different type of drill, a high torque electric micromotor, at speeds of less than 100,000 rpm without air streams, 60 times fewer droplets were produced than with the air turbine drills. The researchers acknowledged that slower drills are less efficient and cannot be used all the time or in every procedure.

Other factors that affect the speed of aerosol generation and movement are the positioning of the patient, the ventilation system in the room and the size and shape of the room.

“This important work describes the basic mechanisms that lead to the features of dental aerosols that we currently consider to be high risk,” said study co-author Professor Owen Addison of King’s College London’s Faculty of Dentistry, Oral & Craniofacial Sciences. “This has enabled us to choose drill parameters to keep our patients and the dental team safe at this difficult time.”

An article in the Journal of Periodontology found other effective ways to limit infection spread from aerosol-generating dental procedures. First and foremost, patients should be screened for symptoms of COVID-19 or given a point-of-care (POC) test to lower the likelihood that an infected patient undergoes a procedure. Additionally, dental offices can be outfitted with systems for air cleaning, surface decontamination and for creating a negative pressure in the room. These measures, along with proper personal protective equipment (PPE) use by the dental staff, will mitigate the likelihood of infection spread during procedures.   

Earlier research by the American Dental Association found that, although dentistry is considered a high-risk profession, the actual incidence of COVID-19 infection among dentists was very low. By June 2020, only 1% of dentists had contracted the virus, likely due to the stringent safety measures and PPE standards in place.

Dentists are reminded to visit the New York State Dental Association website for up-to-date information on NYS Health Law alerts and more. MLMIC also encourages dental providers to monitor all COVID-19-related updates on our resources page and continue to consult our detailed blog post on safely managing practices during the pandemic.