Bacteriology of periodontal disease.

The microbial flora associated with the periodontal tissues in health and disease is extremely complex, and much research is being directed toward identifying those species that may be etiologic agents or that can be used as prognostic indicators. Recent work has resulted in changes in the taxonomic position of several periodontal species and the recognition that several others, particularly species of Eubacterium and Peptostreptococcus, as well as a novel oral spirochete, may be important in disease. New rapid techniques for identifying and enumerating the periodontal flora are being applied to cross-sectional and longitudinal studies to assess the significance of the various species; the DNA probe and immunologic detection methods demonstrate both advantages and limitations when compared with methods based on determining the predominant cultivable flora.