Determining the progression of human immunodeficiency virus (HIV) type 1 infection based on cellular and clinical markers has become increasingly important. Although a number of studies have shown a relationship between the presence of certain oral lesions and progression to AIDS, few data exist regarding the association with T lymphocyte counts. In this study, the question of whether intraoral lesions preceded or were the consequences of changes in T lymphocyte counts was examined. A total of 116 HIV-infected patients participating in two randomized double-blind placebo-controlled trials of zidovudine at the University of Minnesota AIDS Clinical Trials Unit (ACTU) were enrolled in a prospective dental study. Patients were examined for the presence of hairy leukoplakia, candidiasis, herpes simplex, herpes zoster, aphthae, atypical gingivitis, HIV-associated periodontitis, and necrotizing ulcerative gingivitis, as well as other oral lesions, every 3 months for a maximum of four examinations over a 1-year period. T lymphocyte counts before and after each patient's oral examination were obtained. No significant differences were found at examination 1 for differences in gender, race, age, education, tobacco smoking status, ethanol consumption habits, duration in ACTU drug protocol, duration in dental study protocol, or mean T lymphocyte counts between individuals with or without oral lesions at any time in the dental study.(ABSTRACT TRUNCATED AT 250 WORDS)