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 ≥4 mm in the third molar region, one quarter had a PD ≥5 mm. Twenty-four percent of the subjects had at least 1 tooth that had an increased PD ≥2 mm in the third molar region at follow-up. If subjects had at least 1 PD ≥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 ≥2 mm (P < .001).

Conclusion

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