Kim Loos Dr. Kimberly A. Loos practices general dentistry in San Jose, California. She is also a clinical instructor at University of Pacific School of Dentistry and an editor for Dentistry On-Line. The answer to your question is of interest to health care providers and patients alike.
Most studies show the presence of virus in oral fluids to be sporadic.
When HIV is detectable in saliva, the levels are extremely low. This study showed that dental work had no effect on the presence of virus in the saliva. Although HIV has been found in the oral cavity, transmission via saliva has not been implicated. For example, when the virus is mixed with saliva, the ability of the virus to infect white blood cells, namely lymphocytes, is reduced or eliminated. The specific factors causing this inhibition have not been identified, but this may explain the extremely low levels of HIV in saliva.