Site-specific association between supragingival plaque and bleeding upon probing in young adults

The aim of the present study was to consider supragingival plaque as a risk factor for gingivitis in a group of young adults without destructive periodontal disease. A total of 127 subjects, 17 to 30 years of age, participated. Periodontal probing depth, clinical attachment level as well as bleeding upon probing and supragingival plaque was assessed at 6 sites of every tooth present. The individual odds ratios between plaque and bleeding ranged between 0.237 and 66.6. 23% volunteers had an odds ratio of below 1.2. Only 15% individuals presented with an attributable risk of supragingival plaque for bleeding upon probing of 50% or more. Overall, the odds of bleeding, adjusted for periodontal probing depth, was increased by 67% in the presence of plaque. Large differences were observed at different teeth with the highest odds ratio at mandibular premolars with 2.557 (95% confidence interval 2.033-3.216) and the lowest at maxillary molars with 1.355 (1.161-1.732). It was concluded that there was high interindividual and intraindividual variation of the relative risk for bleeding in the presence of plaque. The observed low overall relative risk has important consequences in educational and health care programmes since the risk of supragingival plaque which is actually attributable for the observed bleeding on probing may be rather small.