United States military personnel and dependents who have tested seropositive for the Human Immunodeficiency Virus (HIV) are given medical examinations and treatment at Walter Reed Army Medical Center. Subjects are also invited to participate in a research protocol to study the natural history of HIV infection, conducted by the Walter Reed Army Institute of Research. An oral health research component conducted by NIDR is a part of this natural history study. Subjects were enrolled in the oral health component from 1989 to 1994 and returned approximately every six months for re-evaluation of their oral health status and for other tests and procedures. The oral component includes examinations by an oral medicine specialist for soft tissue lesions, periodontal conditions (gingival bleeding, plaque and calculus indices, presence of inflammation/destruction of interdental papillae, and presence of erythematous banding), and caries, and the acquisition of plaque, saliva, and mucosal smears for tests for candida. A questionnaire obtains information from subjects on demographic characteristics, health care utilization, oral symptoms, oral hygiene practices, and tobacco and alcohol intake. Information is obtained from the main Walter Reed Army Institute study on other factors such as Walter Red staging, CD4+ counts, and medications. The purpose of the study is to document the prevalence and incidence of oral pathologic conditions in relation to the stage of HIV infection and systemic disease. Risk factors associated with these conditions are also characterized, and the role of oral manifestations as early predictors or markers of disease progression are studied. Areas of emphasis are mucosal diseases, periodontal conditions, candida infections, and salivary constituents. Field data collection for this study ended in August 1994. Approximately 814 persons were seen at least once. About 40% of these persons have had 3 or more exams and 13% had at least 5 exams.