The oral cavity is an important and frequently undervalued source of diagnostic and prognostic information in patients with HIV disease. A variety of conditions affecting oral mucosal tissues may arise either de novo or secondary to lesions elsewhere in the body and may provide the genitourinary physician with additional knowledge of individual patients' biological responses to their HIV infection. The mouth may also be a primary source of infection in any individual, which may spread via the mucosal associated lymphoid tissues or stimulate systemic inflammatory immune responses via chronic low grade entry of bacterially derived antigenic/virulence factors into the gingival vasculature.^{1, 2} Indeed, the gingival and periodontal tissues are unique in structure, since they form the point at which internally linked hard tissues breach the epithelial surface rather like a compound bone fracture. This junction of tooth and gingiva provides a potentially weak barrier through which bacteria and their virulence factors (for example, lipopolysaccharide) may enter the connective tissues and systemic circulation (see fig 1). In this respect, maintaining a low microbial load within the mouth should be seen as an essential component of preventative treatment regimens in HIV positive patients.

When one considers that approximately 98% of lymphocytes reside in the tissues rather than circulation, then the clinical condition of the oral mucosa and periodontal tissues may potentially provide valuable information, additional to viral load or CD4 counts, that may help in the management of HIV infected patients.

With the basic biology of both the oral mucosa and periodontal tissues in mind, the importance of oral lesions in HIV infection can be …