Aerosol, a health hazard during ultrasonic scaling: A clinico-microbiological study

The recent emergence of the novel coronavirus has many dental professionals concerned about safety, not only for the clinician but also for the patients. Aerosols are produced regularly in dental offices from ultrasonic scalers, air polishers, air-water syringes, and handpieces. In a clinic-microbiology study published in the Indian Journal of Dental Research, the authors evaluated aerosol contamination during ultrasonic scaling.1

The description of aerosols used in this study is “the suspension of liquid or solid particles containing viruses and bacteria which are suspended in gas”, they go on to state it is suspended for a few seconds, but I believe that may be subjective. It is well documented that the oral cavity harbors bacteria and viruses from the respiratory tract, saliva, and biofilm. One study cited by the authors concluded: “aerosols generated from the patients’ mouth contain millions of bacteria per cubic foot of air”.

This study was a single-center, double-masked, randomized study. Before beginning the study, the area was sterilized through fumigation of each cubicle. Two agar plates were placed in each operatory, one was placed in the center of the operatory (before scaling procedures) while the other was placed 40 cm away from the working area, near the patient’s chest for 20 minutes during scaling. Each patient was positioned the same, the same clinician performed all procedures, only one patient was treated per day to eliminate the possibility of cross-contamination from lingering aerosols. A piezo electronic scaler was used with constant frequency and constant level of coolant. A motorized suction was used as well. After treatment was completed the agar plates were sent to a lab for microbiological analysis.

The microbiological analysis was done by a single microbiologist. The agar plates were cultured aerobically for 3 days, after which gram staining, catalase tests, coagulase tests, and colony-forming units were counted. The results were in line with other studies, high levels of microorganisms after ultrasonic use with the greatest concentration within 2 feet of the patient. Well within the area the clinician is positioned during treatment. This study, along with several others shows that the use of ultrasonic scalers is one of the greatest producers of airborne contaminants in dentistry. The authors go on to say, “Recent studies have highlighted the spread of infection through the air resulting from the most intensive aerosol and splatter emission that occurs from an ultrasonic scaler tip and bur on a high-speed handpiece”.

Controlling and minimizing the spread of bacteria and viruses through aerosols is an important issue in dentistry, even more so with the current issue with COVID-19. Not only for the health of the dental professional but also for the health of patients.

In conclusion, the authors suggest, “aerosols and splatters produced during dental procedures have the potential to spread the infection to dental personnel and other people in the dental clinic. It is difficult to completely eliminate the risk posed by dental aerosols; it is possible to minimize the risk with relatively simple and inexpensive precautions such as personal barrier protection, preprocedural mouth rinse with an antimicrobial mouth rinse before treatment, use of high volume suction apparatus, and use of rubber dam where applicable.”

What precautions will you make when you go back to working clinically? Have you been utilizing the HVE when using an ultrasonic scaler? What are some other changes you would like to see going forward?

Singh A, Shiva Manjunath RG, Singla D, Bhattacharya HS, Sarkar A, Chandra N. Aerosol, a health hazard during ultrasonic scaling: A clinico-microbiological study. Indian J Dent Res. 2016;27(2):160–162. doi:10.4103/0970-9290.183131

More Science Sunday Articles: https://ataleoftwohygienists.com/sciencesunday/