A small number of bacterial pathogens in the human oral cavity cause t
he different forms of periodontal disease. Of the approximately two hu
ndred different oral bacterial species, about a dozen have been associ
ated with these diseases including localized juvenile periodontitis, r
apidly progressing periodontitis, and adult periodontitis. These speci
es include Actinobacillus actinomycetemcomitans, Bacteroides forsythus
, Campylobacter rectus, Porphyromonas gingivalis, and Prevotella inter
media. Several rapid methods have been developed to detect these speci
es in clinical samples. These include immunologic methods such as immu
nofluorescence, nucleic acid assays such as DNA-DNA hybridization in d
ot blots, and enzyme assays. Immunofluorescence microscopy has been us
ed to determine the prevalence and relative proportions of these patho
gens in dental plaque samples from 194 subjects including HIV-infected
and uninfected male homosexuals and intravenous drug users.