Third molars associated with periodontal pathology in older Americans

The study goal was to assess the association between the presence of visible third molars and periodontal pathology in a community-dwelling sample of middle-aged and older adults.

Data were obtained between 1996 and 1999 on 6,793 persons aged 52 to 74 from the Dental ARIC Study, a substudy of the Atherosclerosis Risk in Communities Study. The main independent variable was presence or absence of third molars assessed visually, and the dependent variable was assessment of periodontal disease as measured by pocket depth of 5 mm or greater (PD5+). Periodontal measures included pocket depth, gingival recession, and attachment level on 6 sites per tooth on all remaining teeth. Second molars were compared for periodontal pathology based on the presence or absence of a visible third molar in the same quadrant. Associations were determined using odds ratios and 95% confidence intervals. Weighted multivariable models were fit using logistic regression, and variances were adjusted to account for the clustering of quadrants within persons with the use of SUDAAN (Research Triangle Institute, Research Triangle Park, NC).

A visible third molar was associated with 1.5 times the odds of PD5+ on the adjacent second molar, while controlling for other factors associated with the presence of third molars and periodontal disease. Other factors positively associated with PD5+ in the model were male gender, older age, smoking, and irregular and episodic dental visits.

The finding of more severe periodontal conditions associated with visible third molars in these middle-aged and older adults indicates that third molars may continue to have a negative impact on periodontal health well into later life. The relationship between third molars and periodontal disease pathogenesis deserves further study using longitudinal data.