Prevalence of third molars with caries experience or periodontal pathology in young adults

We assessed the prevalence of caries experience and periodontal pathology on asymptomatic third molars in young adults.

Healthy subjects with 4 asymptomatic third molars were enrolled in an institutional review board-approved study during a 5-year period. Full mouth periodontal probing, 6 sites per tooth, was the measure of clinical periodontal status. The presence or absence of occlusal caries experience (carious lesions or restorations, including sealants) on third molars and on any surface of the first and second molars were assessed using a visual-tactile examination and panoramic radiographs. The primary outcome measures were at least 1 periodontal probing depth of at least 4 mm versus none and caries experience versus no caries experience.

The data were analyzed from 409 subjects, who averaged 25 years old. More subjects were female (53%) and white (76%). More subjects had at least 1 periodontal probing depth of 4 mm or deeper on a third molar (55%) than on the distal of a second molar (46%). These findings were more likely to be detected around a third molar in subjects with all third molars at the occlusal plane (72%) than in subjects with at least one third molar below (33%). Overall, fewer subjects were affected by third molar caries experience than first or second molars (24% vs 73%, respectively). Of the subset of subjects with all four third molars at the occlusal plane, 26% were affected by both third molar periodontal pathology and caries experience and 16% were caries and periodontal pathology free.

In these cross-sectional analyses, periodontal pathology was detected more frequently on third molars than on first and second molars and caries experience was detected more frequently on first and second molars than on third molars.