periodontitis /per′ē·ō′dontī″tis/ , inflammation of the periodontium caused by a complex reaction initiated when subgingival plaque bacteria are in close contact with the epithelium of the gingival sulcus. Injury arises from toxins and enzymes produced by the bacteria and from host-mediated defense responses. Apical movement of the junctional epithelium, which indicates attachment loss and alveolar bone loss, is diagnostic of periodontitis. See also periodontal disease.
