Highlights

Biological (Cross-Infection) Hazards

Dentistry is unique in that clinical staff are in direct or indirect contact with traumatized tissues, saliva, and blood on a daily basis. All members of the dental team are at risk of exposure to Hepatitis B virus (HBV), HIV infection, and other types of communicable infections.

In the United Kingdom for example, the carrier rate HBV in the general population is 0.5%, while dentists have a carrier rate of approximately 1.6%.

Several of the common viral agents that can cause hepatitis have been detected in body fluids including saliva and blood. The viruses most commonly implicated include hepatitis A virus (HAV), HBV, and hepatitis C. In a study done by Watt HIV/AIDS was believed to be very similar to eye injury and mercurial poisoning in terms of rate of concern amongst dental personnel.

Potential Biological Hazards  Summary of Major Control Strategies 
  w.r.t. Engineering (Technical aspect) w.r.t. Administrative  w.r.t. Personal Protection Equipment (PPE)
Exposure to biological agents in blood and saliva of patients through contact with blood and saliva or through contact with contaminated needle or sharp instruments (including orthodontics wires)  Equipment to minimize formation of aerosols (rubber dams, high-speed evacuation, etc.). Obtain medical history of patients. Engineered needle stick prevention devices. Availability of sharps containers for disposal. Proper disinfection of instruments and decontamination of environmental surfaces, lab supplies and materials. Vaccines.  Compliance with all infection prevention and control practices. No recapping of needles (even if multiple injections in same patient). Safe work procedures to minimize formation of aerosols where possible (proper patient positioning, etc.). Proper disposal of waste materials. Immunization program. Worker education.  Use of gloves, eye and face protection when splashes or splatters arepossible. Gowns or uniforms that should be changed daily or when contaminated. 
Exposure to respiratory infectious disease through droplet transmission, including splatters from body fluids and projectiles while using high speed devices.  Medical history of patients. Vaccines.  Compliance with all infection prevention and control practices. Immunization program. Worker education.  Use of gloves, eye and face protection when splashes or splatters are possible. Gowns or uniforms that should be changed daily or when contaminated. 
Exposure to respiratory infectious disease through airborne transmission  Medical history of patients. Vaccines.  Good housekeeping practices. Compliance with all infection prevention and control practices. Immunization program. Worker education.  PPE based on the risk assessment may include gloves, respiratory protection, eye protectionand other protective clothing. 
Exposure to environmental biological contaminants from ventilation systems, water or food  Maintenance of ventilation systems. Early spill clean-up. Preventive maintenance of ventilation systems and water supply systems with regular testing to ensure proper functioning. Early detection and remediation of mould.  Infection prevention and control practices related to building maintenance and food preparation. Protocols for construction and renovation projects that reduce contamination. Worker education.  Use of proper PPE when cleaning contaminated environmental surfaces, including gloves, respiratory protection, and eye protection.