Did Dental Aerosols Spread COVID-19? What a 2021 Study Found
During the COVID-19 pandemic, one worry was that the fine spray from dental drills and cleaning instruments would carry the virus from a patient's saliva across the room. A study published in May 2021 by researchers at Ohio State University found that most of the microbes in that spray came from the water used during treatment, not from saliva, and the virus was not detected in any of the spray samples. The study was small and done with infection-control measures in place, so it supports those measures rather than showing that dental care carries no risk.
What question did the study ask?
Dental instruments such as high-speed drills and ultrasonic scalers produce a fine mist. Earlier studies had shown that bacteria land on clinicians' faces, the patient's chest and surfaces several feet away. Those studies mostly grew bacteria on plates. They could not say where the microbes came from, and saliva was assumed to be the source. At the start of the pandemic, that assumption led to wide closures of dental offices.
The Ohio State team asked a narrower question: when aerosols land around the dental chair, how much of what they carry actually comes from the patient's saliva?
How was it done?
Patients: 28 adults treated at Ohio State's College of Dentistry between May and July 2020, during ultrasonic cleaning, implant surgery or fillings with a high-speed drill.
Samples: saliva and the irrigation water were collected before each procedure. Afterward, droplets that had condensed on the clinician's face shield, the patient's bib and a spot about six feet away were collected.
Testing: genetic sequencing identified the bacteria in each sample and traced them to their likely source. A separate test looked for the COVID-19 virus.
Precautions in place: patients used a mouth rinse before treatment, and high-volume suction was used in the mouth.
What did it find?
About 78 percent of the microbes in the aerosol samples could be traced to the irrigation water.
Saliva contributed very little. The median contribution was zero.
Low levels of the virus were found in the saliva of several patients who had no symptoms, but none was found in the aerosols from their procedures.
The authors concluded that, with standard infection-control measures such as a mouth rinse before treatment and high-volume suction, dental treatment did not appear to increase the risk of passing the virus from patients without symptoms.
What are the limits?
It was one center and 28 patients.
It measured where microbes landed, not whether anyone became infected.
It did not address the spread of a virus through talking, coughing or sneezing in a waiting room or treatment room, which the lead author noted still carries risk.
The results apply to treatment done with the precautions the study used.
What does it mean now?
This study is part of the record of how dentistry responded during the pandemic. Its main lesson still holds: routine infection control, including clean water lines, suction and barrier protection, is what limits the spread of germs in a dental office.
If you have a health condition that affects your immune system and have questions about dental visits, tell us when you schedule. You can read more about dental care for people with complex medical needs. Patients in Jacksonville can contact our office with any questions before a visit.
Sources
Meethil AP, Saraswat S, Chaudhary PP, Dabdoub SM, Kumar PS. Sources of SARS-CoV-2 and other microorganisms in dental aerosols. J Dent Res. 2021;100(8):817-823. doi:10.1177/00220345211015948. Retrieved via PubMed.
Ohio State University. Press release on dental aerosols and COVID-19, May 2021.
About the author. CJ Henley, DMD, is a general dentist in Jacksonville whose practice focuses on cosmetic and restorative dentistry, dental implants and dental care around head and neck cancer. Meet Dr. Henley.
CJ Henley, DMD, PA · 3675 Hendricks Avenue, Jacksonville, FL 32207 · 904-398-1549
Updated October 2026.