[HIV and dentistry. Part 3. HIV infection: pathogenesis, epidemiology, definitions and classification].

The acquired immunodeficiency syndrome (AIDS) is caused by a retrovirus, the human immunodeficiency virus (HIV), that selectively deteriorates cell-mediated immunity. Consequently fatal opportunistic infections and/or malignancies occur. In this paper the pathogenesis and the epidemiology of HIV infection are described. In addition the 1993 revised classification for HIV infection and the expanded surveillance case definition for AIDS are presented.