Purpose: This study was conducted to investigate the incidence and predictors of hypercementosis in mandibular third molars using cone beam computed tomography.

Methods: Using a retrospective approach, 1,160 cone beam computed tomography image sets were analyzed. Two oral radiologists independently evaluated the image sets based on four severity grades: 0, no hypercementosis around the root; 1, hypercementosis surrounding less than half of the root surface; 2, hypercementosis surrounding more than half of the root surface; and 3, hypercementosis surrounding the entire root surface. Hypercementosis was identified as a dark or light layer. Statistical analyses of relationships between hypercementosis incidence and possible predictors (e.g. age, sex, impaction, and occlusion) were performed using chi-square test or Fisher’s exact test; logistic regression was used for multivariate analysis.

Results: The severity of hypercementosis increased with age, and the incidences were as follows: ≤19 years, 0%; 20-24 years, 14.1%; 25-29 years, 57.7%; 30-39 years, 83.0%; 40-49 years, 92.7%; 50-59 years, 93.4%; and ≥60 years, 96.8%.

Conclusion: The observed incidences of hypercementosis were relatively higher than in previous studies, and the incidence was significantly lower for occluded teeth than for non-occluded teeth.