Bloodborne Pathogens & Aerosols

A visible spray is created during the use of rotary dental and surgical instruments (e.g., handpieces, ultrasonic scalers) and air-water syringes. This spray contains primarily a large-particle spatter of water, saliva, blood, microorganisms, and other debris. This spatter travels only a short distance and settles out quickly, landing either on the floor, nearby operatory surfaces, the dental health care personnel providing care, or the patient. This spatter can commonly be seen on faceshields, protective eyewear, and other surfaces immediately after the dental procedure, but after a short time it may dry clear and not be easily detected. The spray may also contain some aerosol. Aerosols take considerable energy to generate, consist of particles less than 10 microns in diameter, and are not typically visible to the naked eye. Aerosols can remain airborne for extended periods of time and may be inhaled. Aerosols should not be confused with the large-particle spatter that makes up the bulk of the spray from handpieces and ultrasonic scalers. To prevent contact with splashes and spatter, dental health care personnel should position patients properly and make appropriate use of barriers (e.g., faceshields, surgical masks, gowns), rubber dams, and high-volume evacuators.
Although it is known that bloodborne pathogens can be transmitted through mucous membrane exposure, there are no known instances of a bloodborne pathogen being transmitted by an aerosol in a clinical setting. In studies conducted in dental operatories and hemodialysis centers, hepatitis B surface antigen could not be detected in the air during the treatment of hepatitis B carriers, including during procedures known to generate aerosols. This suggests that detection of HIV in aerosols would also be uncommon, since the concentration of HIV in blood is generally lower that that of HBV. Finally, detection of HIV in an aerosol would not necessarily mean that HIV is readily transmissible by this route. In the health care setting, the major risks of HIV infection are blood contact due to percutaneous injuries and, to a lesser extent, mucous membrane and skin contact. The possibility that HIV may be transmitted via aerosolized blood must be considered theoretical at this time.