Bloodborne Pathogens & Aerosols
In dentistry, the diseases we are most concerned about are those caused by bloodborne pathogens (BBP). Examples are hepatitis B and C and human immunodeficiency virus (HIV). Transmission may occur from a patient to a dental health care provider (DHCP), from a DHCP to a patient, or from one patient to another patient. The best way to prevent the transmission of BBP is adherence to Standard Precautions1.
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.
Selected References and Additional Resources
Bond WW, Petersen NJ, Favero MS, et al. Transmission of type B viral hepatitis via eye inoculation of a chimpanzee. J Clin Microbiol 1982;15:533–534.
Cole EC, Cook CE. Characterization of infectious aerosols in health care facilities: an aid to effective engineering controls and preventive strategies. Am J Infect Control 1998;26:453–464.
Favero MS, Bolyard EA. Microbiologic considerations. Disinfection and sterilization strategies and the potential for airborne transmission of bloodborne pathogens. Surg Clin North Am 1995;75:1071–1089.
Heinsohn P, Jewett DL. Exposure to blood-containing aerosols in the operating room: a preliminary study. Am Ind Hyg Assoc J 1993;54(8):446–453.
Johnson GK, Robinson WS. Human immunodeficiency virus-1 (HIV-1) in the vapors of surgical power instruments. J Med Virol 1991;33:47–50.
Mangram AJ, Horan TC, Pearson ML, Silver LC, Jarvis WR, the Hospital Infection Control Practices Advisory Committee. Guideline for the prevention of surgical site infection, 199external icon. Infect Control Hosp Epidemiol 1999;20:247–280.
Miller RL. Characteristics of blood-containing aerosols generated by common powered dental instruments. Am Ind Hyg Assoc J 1995;56(7):670–676.
Petersen NM, Bond WW, Favero MS. Air sampling for hepatitis B surface antigen in a dental operatory. JADA 1979;99:465–467.
Petersen NJ. An assessment of the airborne route in hepatitis B transmission. Ann NY Acad Sci 1980;353:157–166.
- Standard Precautions are the minimum infection prevention practices that apply to all patient care, regardless of suspected or confirmed infection status of the patient, in any setting where health care is delivered. These practices are designed to both protect DHCP and prevent DHCP from spreading infections among patients.