Organic acid producing anaerobic bacteria are implicated in the development and progression of gingivitis and periodontal disease (Brill, 1962; Kleinberg, 1974). The disease process manifests as periodontal inflammation and tissue destruction (Oliver et al, 1969). Although relatively crude methods are used for routine clinical diagnosis and monitoring of periodontal disease (eg, probing for gingival pocket depth and bleeding), sensitive and reproducible measures of periodontal disease have been validated (Oliver et al, 1969; Löe et al, 1965; Egelberg, 1964; Golub et al, 1976; Borden et al, 1977).