Cross-sectional assessment of caries and periodontitis risk within the same subject.

Dental caries and chronic periodontitis may be synergistically associated, negatively associated, or completely independent. The present report examines this relationship by comparing the susceptibility to chronic periodontitis and caries within the same individual. From an 800-patient sample, a periodontitis risk score was derived by radiographic assessment of bone loss in quarters of optimum bone height and obtaining for each subject a mean score based on all measurable surfaces. Similarly the caries risk was determined radiographically from the total decayed and filled teeth (DFT), as a percentage of the total teeth measured. The Mantel-Haenszel technique was used for analysis of the relationship between periodontitis and caries and data was stratified on four categories of age, sex, and numbers of teeth present. This analysis revealed no systematic patterns, indicating that the risks of caries and periodontal diseases are unrelated (chi 2 = 0.00; 1 df; P greater than 0.50). In addition, a regression analysis, which was controlled for sex and age, indicated a marked lack of association between caries and periodontitis (P = 0.94). Thus, although these common diseases share putative etiologic factors such as oral hygiene practices and dental attendance pattern, the major risk factors are probably quite different.