What in the World Do We Do Now About Masks?

Margaret Scarlett, DMD


Dental practice changed forever last year, distinguishing aerosol-generating procedures (AGPs) from non-AGPs, while adding air quality controls to concerns about our day-to-day operations. It won’t go back, ever!

Now that COVID-19 cases are declining in most areas, determining the right kind of respiratory protection program for you and your patients is essential in your practice. But it takes some sleuthing. We have a few clues and partial answers.

The Centers for Disease Control and Prevention (CDC) issues guidance that includes words such as “must,” “should,” and “may,” based on science. So, I will use these words since I know them so well. 

What exactly is mandated? Nothing yet. Whew!

But we got a clue when the Occupational Safety and Health Administration (OSHA) issued seven violations to a Masschusetts dental practice, including failing to provide fit testing for N95 masks to employees last September, among other infractions. OSHA has largely exempted dentistry from its emergency temporary standard, but not from every office having a written plan.

Best Practices for Masks

N95 masks should be the minimum standard for dental personnel in patient care for most dental procedures until more science definitively states otherwise.

Since OSHA issues its final guidance consistent with the CDC, and the CDC hasn’t updated its infection control guidance for dental settings since December 2020, look for the CDC’s recommendations first, and then OSHA’s. I always hated those unpredictable CDC clearance processes, with last minute (but usually correct) input from infectious disease physicians.

Let’s talk about guidelines for clinicians’ masks:

  • When “must” we implement a respiratory protection program? Answer: Always!
  • When “should” we use an N95 mask? Answer: Nearly always for all procedures, except exams.
  • What about using powered air-purifying respirators or elastomeric masks? Answer: You “may” use them sometimes during AGPs.

The bottom line is that you “must” match your mask to what you are doing. That’s clear.

What about patient mask compliance? Should patients wear masks into the office, even if they are vaccinated? Yes, keep doing that for now, until further word from the CDC. Even though patients are likely to be fully vaccinated, with 45.3% of the United States population fully vaccinated as of this writing, patients “may” opt for masks.

Encourage patients to use masks temporarily. With the B.1.617.2 delta variant of SARS-CoV-2 circulating in the United States, it’s a good idea. While delta variants represent only a tiny fraction of virus in the United States now, partially vaccinated patients and unvaccinated patients “must” be wearing masks since they are likely to be unprotected from it and, possibly, from any other variants that may emerge worldwide.

What’s more, masks “must” be worn by patients with disabilities, compromised immune systems, or allergies to vaccines. And if delta or other emergent variants start to pose greater challenges even for some fully vaccinated people, then perhaps they, too, “may” prudently wear masks temporarily, depending on whether their local health departments say community transmission in their county is high or moderate.  

The Risks of AGPs

How do we characterize AGPs? Well, that is the big question. Without more science, we still don’t know with COVID-19. But we know enough about other respiratory diseases that we “should” have been wearing N95 masks long ago because of measles, tuberculosis, MERS, SARS-1, and seasonal influenza.

Oh well. Coulda, woulda, shoulda. The CDC didn’t let me say it then, but probably will now. For example, in 1986, my CDC colleagues noted that children in a pediatric office transmitted measles at distances of 10 feet or more.

By the way, measles is on the rise in the United States because of the antivax movement over the last 20 years. In the 1990s, tuberculosis transmitted easily among airplane passengers meant that a dental office was vulnerable. If that isn’t enough, SARS and MERS reinforced the need for masks in dental practice for respiratory protection in the 2000s.     

Measurement of AGPs is critical. While a recent article in Lancet suggested getting rid of the term AGPs, I disagree. Rather, like most oral health problems, we need a refined measurement or surveillance system to measure AGPs for different dental procedures and in different offices.

We need our interdisciplinary colleagues in environmental microbiologists, air laboratorians at the National Institute for Occupational Safety and Health (NIOSH), statistical modelers, and trusty heating and air-conditioning personnel as well as lots of proper air samples of different dental procedures.

Dental offices “should”  probably have six room air exchanges per hour in operatories, like a regular hospital or healthcare room at least. Until more science is available. Add to this the need for improved ventilation and air de-densifying.

Why do we need to take these precautions? Because even though the ADA is reporting low rates of infection, there is selection bias by dentists of sampling with wide variability in community transmission, based on variations in reporting from local and state health departments. 

For example, last year, Meng et al. reported from a Chinese dental school that eight of 169 dental personnel were infected, which is about a 5% infection rate, while the community transmission was about twice that.  

Better science about the risks for dentists to be infected with COVID-19 comes from the United Kingdom. The Journal of Dental Research study, as opposed to ADA data, showed higher rates of infection among dental personnel, or three times the general population. This study also found that about 35% of Black and 19% of Asian dental professionals, versus 14.3% of White dental professionals, were infected with COVID-19.

What measures might be important for assessing the output of AGPs? Data shows that the size, speed, measurement, humidity, viral or bacterial load of the patient, centrifugal force of a 200,000-rpm electric or 400,000-rpm air turbine handpiece, how the operators position their evacuation systems, and which quadrant they are working in all matter. However, prior studies have shown that while the virus may be present, the volume of the virus might not be enough to spread disease.  

What should we do now, while the science is emerging? Let’s begin to think about aerosols like “smoke” and droplets like “rain,” and let’s get to a place where we start to measure the output of AGPs of different dental procedures with personal and environmental samples. (Where have you been, NIOSH and National Instititute of Dental and Craniofacial Research?) And then there are models in which aerosols (or smoke) may transmit more infections after masking and social distancing are in place. 

Finally, we need a panel at the CDC for building the bridge between infectious and chronic diseases. Really. We must!

Along with vaccination, pandemic preparedness, and response, dentists “must” be included in infectious disease testing and in health department surveillance. We could with electronic records, and by doing so we could add to known community surveillance tools and studies. Let’s start with pilots now so we aren’t settling back into complacency until the next pandemic. Which is coming. When? We don’t know, but it will. 

Remember, as dentists, we know we are always the first to get those cancelled appointments because of flu in the fall! And don’t forget to include teledentistry in your practice, now, to accommodate the new realities with patients, as well as any other pandemic or infectious disease that “may” come along.

Dr. Scarlett is an infectious and chronic disease prevention specialist, practicing dentist, speaker, author, and consultant. For 30 years, she has provided expert guidance on infectious diseases and infection control as a consultant to the CDC, the World Health Organization, the Pan American Health Organization, the United States Agency for International Development, the American Red Cross, and many consumer health companies. She is a member of the ADA Working Group on Teledentistry and also provides a variety of strategic consulting services for dental companies and associations, including strategic planning, organizational design and development, technical and white papers, new product development and testing, and leadership for dental advisory committees. She can be reached at mscarlett@scarlettconsulting.com and (404) 808-­9980.

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