Airborne contamination during dental procedures may come from a variety of sources. Foremost among these are: dental instrumentation, salivary, and respiratory sources.33 Dental handpieces, ultrasonic scalers, and the air-water syringes used routinely in dental practice are capable of producing aerosols, which are usually a mix of air and water derived from these devices and the patient’s saliva.34 Dental instruments, surfaces within the dental operatory, and dental equipment, when improperly decontaminated, cleaned, sterilized, and stored, or disinfected can also serve as fomites and contribute to cross-infection.
The oral environment is naturally wet and contains a high number of microorganisms. Dental plaque is a major source of such organisms, containing more than 700 known microbial species,35 but the mouth also harbors bacteria from the respiratory tract, including the nasopharynx and the lower pulmonary system.30 Gingival crevicular fluid, debris from tooth preparation, and dental materials may also be aerosolized during dental procedures and contribute to disease transmission.36,37
The most intense aerosol and splash and splatter has been shown to occur during use of ultrasonic scalers and high speed handpieces without a rubber dam;30,32,36 however, aerosols in the dental setting have also been associated with the use of low-speed handpieces, air/water syringes and patient coughing.34 Because of the ability of aerosols to remain suspended in the air and travel further than splash and splatter, and distant contamination may occur, and there is potential for disease transmission, even after the infected person has left the vicinity.34,38-40 SARS-CoV-2 can survive on such environmental surfaces for prolonged periods of time.34,41 Table 1 describes the risk of aerosols associated with dental procedures.