In March 2020, dental offices shut down to all but emergency care, but they have since resumed elective procedures—with precautions in place and consideration of local health regulations. The American Dental Association and the Centers for Disease Control and Prevention (CDC) have provided guidance to dental practices on delivering safe care to patients and protecting dental workers during the pandemic.
According to the O*NET, a database maintained by the U.S. Department of Labor, and the New York Times, dentists are exposed to diseases and infections 95 percent of the time, while dental hygienists are exposed 100 percent of the time, and dental assistants follow with a 96 percent exposure rate. Dentists are in close contact with their patients while they administer and assess oral hygiene. In fact, dental professionals are close to their patients. On a scale of proximity, dentists and dental assistants score 99 percent, while dental hygienists are a bit higher with 100 percent.
There’s no doubt, dentists are susceptible to catching the virus due to the confined spaces of a dental office.
Dental settings have “unique characteristics that warrant specific infection control considerations,” said Michele Neuburger, a dental officer for the CDC’s Division of Oral Health and a member of the CDC’s COVID-19 Response Infection Prevention Control Team. “Dental health care personnel use instruments such as dental [drills], ultrasonic scalers and air-water syringes that create a visible spray that can contain particle droplets of water, saliva, blood, microorganisms, and other debris.”
Many are questioning how to keep their practice open as the pandemic worsens. One of these individuals is Romesh Nalliah, associate dean for patient services at the University of Michigan School of Dentistry. Two professors of mechanical engineering answered his call for help and started searching for the solutions by analyzing aerosol droplets during procedures.
Margaret Wooldridge and Arthur F. Thurnau analyzed the creation and development of the aerosol droplets by using high-speed imaging, particle spectrometers, scanning mobility particle sizing systems, and optical particle counters, while Viyan Kadhium, a School of Dentistry researcher, mapped out the aerosolization of particles.
“We saw huge clouds of droplets that were generated as well. From the sprayed water used to cool the drill and the tooth, droplets would break apart into even smaller droplets. Some droplets bounce off the tooth—like billiard balls or a soccer ball. And the droplets hang around, recirculate and form little clouds right by the mouth of the test mannequins,” said Wooldridge.
They noted that the aerosol suction devices did not suck up all the particles, a hazard if the patient has the virus. The aerosol droplets could land on others in the cubicle or move to other cubicles, as well as contaminate surfaces. The virus could also remain in the air for up to three hours.
The most common solution is plexiglass barriers. They separate individuals who need to be in close proximity to others such as in a dental office. They also protect against surface contamination of other workspaces in the cubicle, reduce the risk for other viruses, and can be disinfected. The plexiglass must be a certain size, determined by the installation area. One idea to keep in mind is that the plexiglass must prevent respiratory droplets from traveling from one individual onto another individual.
While plexiglass could help stop the flow of particles, it also traps them in the same area, a problem for the next patient who will be treated in the same cubicle. Yet, the solution is simple. Plexiglass should only be added to certain treatment areas to maintain sufficient airflow, and it should be sanitized in between patients.
However, Michael Kinzel, assistant professor in Mechanical and Aerospace Engineering at the University of Central Florida, shows how an infected person’s aerosols can spread at a higher concentration inside one of the barriers.
Other precautions can include screening patients before appointments, limiting the use of the waiting room, requiring all individuals in the practice to wear masks, avoiding the use of powered tools, using rubber dams during procedures, and installing high-efficiency particulate air filters. The idea is simple, keep all infected individuals out while also limiting the general number of individuals in the practice.
Though infections in dental settings are rare, the CDC has warned against potential exposure and has advised dental offices to take more guidance. We all have a responsibility to let offices know if we feel sick or have any other symptoms. We’re all in this together—if you’re sick, stay home.