Incidence of hypercementosis in mandibular third molars determined using cone beam computed tomography.

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.