Progression of periodontal disease in the second/third molar region in subjects with asymptomatic third molars.

Purpose: To assess the change in periodontal status over time by periodontal probing depth (PD) in the third molar region.

Subjects And Methods: The data for these analyses are part of a study of subjects enrolled with 4 asymptomatic third molars with adjacent second molars in an institutional review board-approved longitudinal trial. Full mouth periodontal probing was conducted to determine periodontal status at baseline and follow-up. Panoramic radiographs were analyzed for angulation and degree of eruption of third molars. Subjects were categorized as those who exhibited at least a 2 mm change in periodontal PD between baseline and follow-up in the third molar region, the distal of a second molar or around a third molar, and those who did not exhibit a 2 mm or greater change. Subjects with and without changes in PD were compared with Cochran-Mantel-Haenzsel statistics. Level of significance was set at 0.05.

Results: Data from 254 subjects with at least 2 annual follow-up visits were available for analysis. Mean age at baseline was 27.5 years. Median follow-up from baseline to the second follow-up visit was 2.2 years (interquartile range 2.0, 2.6). At enrollment, 59% of the subjects had at least 1 PD > or =4 mm in the third molar region, one quarter had a PD > or =5 mm. Twenty-four percent of the subjects had at least 1 tooth that had an increased PD > or =2 mm in the third molar region at follow-up. If subjects had at least 1 PD > or =4 mm at baseline, 38% had at least 1 PD deepen by 2 mm or more at follow-up. Only 3% of those who had all teeth with a PD of less than 4 mm at baseline exhibited a change of > or =2 mm (P < .001).

Conclusion: Increased periodontal PDs > or =2 mm were often found in the third molar region for asymptomatic subjects with at least 1 PD > or =4 mm at enrollment, clinical measures that indicated increased periodontal pathology, and a deteriorating periodontal condition.