Changes Over Time in the Prevalence of Caries Experience or Periodontal Pathology on Third Molars in Young Adults

PurposeTo assess the prevalence of caries experience and periodontal pathology on third molar teeth compared with first and second molars and teeth more anterior from subjects who had data collected over time in a longitudinal clinical study.Patients and MethodsHealthy subjects with 4 asymptomatic third molars and data for at least 4 years after enrollment were included in these analyses. The presence or absence of caries experience on the occlusal surface of the third molars and any surface of the first or second molars was assessed using a visual-tactile caries examination. Full mouth periodontal probing, 6 sites per tooth, was conducted as a measure of clinical periodontal status. 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 prevalence of caries experience and periodontal pathologic findings at follow-up and the relationship of the occurrence between the third molars and teeth more anterior in the mouth were examined using McNemar's statistics.ResultsThe follow-up was a median of 6.9 years (interquartile range 4.6 to 7.7 years) for 179 subjects, with a mean age of 29 years. More subjects were female (54%) and white (80%). At follow-up, 85% of the subjects had caries experience detected on the first or second molars, and only 50% had a third molar affected. In contrast, at follow-up, the presence of at least 1 periodontal probing depth of at least 4 mm was marginally more prevalent on the third molars than on the first or second molars (56% and 50%, respectively). Fewer subjects had third molars free of caries experience and periodontal pathology at follow-up compared with at enrollment (28% versus 38%, respectively).ConclusionsThe prevalence of both third molar caries experience and third molar periodontal pathology increased from baseline to the follow-up examination. At follow-up, the prevalence of caries experience was greater on the first or second molars than on the third molars, and periodontal pathology were greater on the third molars than on the more anterior teeth.