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Study: Dental Pathogens in Aerosols Mainly Come from Irrigants, Not Saliva

Dealing with a pandemic that spreads via respiratory droplets has created an air of uncertainty and fear. And understandably so.

For many people, these fears have made it difficult to go about their regular daily lives: getting a haircut, shopping for groceries, and ‒ most relevant to our profession  ‒ going to the dentist.

The dentist, in particular, was scary for would-be patients because dental procedures generate a wealth of aerosols, the means by which SARS-CoV-2 can spread. As such, dental care was viewed as high risk for COVID-19 transmissions.

However, recently published study performed by Ohio State University researchers tell a different story.

More specifically, it was found that patient saliva wasn’t a significant source of aerosol microbes created during dental procedures.

In this article, we will explore these new studies and the issue surrounding dental aerosols and COVID-19 transmission in more detail.


Sources of SARS-CoV-2 and Other Microorganisms in Dental Aerosols


The study involved 28 patients receiving the following procedures at Ohio State’s College of Dentistry between May 4 and July 10, 2020:

  • Dental implants
  • Restorations with high-speed drills
  • Ultrasonic scaling procedures


These procedures have one thing in common: they produce a large amount of dental aerosols.

From there, samples of saliva and irrigant (i.e. water-based cleaning solutions for flushing out the mouth) were collected before each procedure. Then, 30 minutes after the procedure was complete, researchers collected condensate (i.e. aerosol remnants) from the dentist’s face shield, patient’s bib, and an area six feet away from the chair.

This study focused on identifying what types of microorganisms were created by the procedures, and determining how much saliva was a factor.

Researchers gathered these samples from personnel, equipment, and other relevant surfaces that aerosols could reach during these various procedures.

Previously, it was found that aerosols landed on a dentist’s face and their patient’s chest, travelling up to 11 feet. At first, this seemed dangerous in the context of a world dealing with COVID-19. But those previous studies only concluded that bacteria existed on people and equipment, never classifying the organisms.

In addition, it was unable to identify their origin. Saliva being the source of most dental aerosols had always been an unproven presumption.

The results of the Ohio University research painted a clear picture: irrigants caused almost 80% of the organisms found in dental aerosols. Saliva, if present, was responsible for just 0.1% to 1.2% of the microbes spread throughout the room.

The main source of organisms in aerosols was the water from the ultrasonic equipment, not saliva. This result was consistent regardless of where the moisture landed.

There were only 8 cases where saliva was found in the condensate, and of those instances, 5 patients failed to use mouth rinse before their procedure.

Also, while 19 patients possessed the SARS-CoV-2 virus in their saliva, it couldn’t be detected in their aerosols.

Further Takeaways From the Research

Purnima Kumar, D.D.S., Ph.D., a professor of periodontology at Ohio State, believes that the research findings add up.

She explains that there’s an estimated 20-to-200-fold diluting effect that irrigant has on saliva.  

Moreover, the Ohio State research findings further support a study in the 2020 American Dental Association Journal that suggested an under 1% COVID-19 positivity rate in dentists.

Dr. Kumar believes these results mean dentists can feel safe in reopening their practices and giving patients the dental care they need.

Good News for Patients and Dentists

You’ve always fought against bacteria in the mouth as a dental professional. It's heartening to know that existing precautionary measures have generally succeeded in protecting you against COVID-19.

Studies like these may also give patients more confidence when visiting the dentist.

The past year-plus has been hard on people’s teeth due to fears of visiting the dentist and the idea that aerosols make for a heightened risk of infection.

Offering this information to your patients will help you put their minds at ease about visiting your practice and receiving much-needed dental care.


The Need for Vigilance Remains

As fantastic as this news is for dental professionals and their patients, more research is still needed regarding the risk of microbial transmission in oral healthcare settings.

Furthermore, these results don’t change the fact that COVID-19 spreads through aerosols. Therefore, sneezing, coughing, and speaking in a dental office can still lead to disease transmissions, meaning vigilance is still necessary for preventing the spread.

at 12:59 PM
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