Infections of the supporting tissues of the teeth include a number of clinically discrete entities and are grouped under human periodontal diseases. Of these diseases, periodontitis is the most common and results when inflammation in the gingiva is extended to the connective tissue attachment and alveolar bone supporting teeth. Microorganisms have been implicated in the etiology of periodontal disease. More than 300 bacterial species reside in the human oral cavity, but only a few of these are believed to be involved in periodontal disease. The closest association between a periodontal infection and an organism exists between Localized Juvenile Periodontitis and Actinobacillus actinomycetemcomitans. A. actinomycetemcomitans is also implicated in certain types of adult periodontitis. The precise role of any bacterial species in periodontal disease is not known. Many investigators noted, however, that the significant periopathogens are able to penetrate epithelial cells. We hypothesize that bacterial invasion of calls and tissues plays a role in the pathogenesis of periodontal disease. Our immediate goal is to develop an in vitro invasion model for A. actinomycetemcomitans utilizing cultured mammalian cells. A number of A. actinomycetemcomitans strains will be screened to determine differences in invasion frequencies. Our long term goal is to look at the role of both the bacterium and the host cell in the invasion process.
