Impact of Removal of Asymptomatic Third Molars on Periodontal Pathology

Purpose: This study assessed the impact of third molar removal on periodontal pathology in subjects with third molars asymptomatic at enrollment. Patients and Methods: Subjects in whom at least 2 third molars were removed were a subsample of healthy young subjects enrolled with 4 asymptomatic third molars in an institutional review board-approved longitudinal study. Full-mouth periodontal probing (PD) data, 6 sites per tooth, were obtained as a measure of periodontal status at each of 3 visits: enrollment, before removal of third molars, and after removal of third molars. Data were aggregated to subject and jaw levels. The oral cavity was divided by jaw into segments: the third molar region including the third molar (12 probing sites), distal to the second molar (4 probing sites), and non-third molars (80 probing sites). A PD >= 4 mm was considered in indicator variable for periodontal pathology. The number and percent of sites with a PD >= 4 mm were calculated from the total number of probing sites across all Subjects. The frequency of subjects with at least one PD >= 4 mm and all third molars removed were compared with the frequency of subjects retaining at least 1 mandibular third molar using Fisher's exact test, with significance set at 0.05. Results: Sixty-nine Subjects had third molars removed: 57% were female, and 77% were Caucasian. The median age at surgery was 26.3 years (interquartile range, 23.3-31.5 yr). The median interval from enrollment to surgery was 2.4 years (interquartile range, 1.5-4.2 yr). The median follow-up after surgery was 9 months (interquartile range, 6.7-15.4 mo). All third molars were removed in 56 subjects; 13 retained at least I mandibular third molar. More Subjects had at least 1 PD >= 4 mm around their mandibular third molars before surgery compared with enrollment (52% vs 45%, respectively). Of the total possible mandibular third molar probing sites, 18% had PD 4 min presurgery compared with 12% at enrollment. Significantly fewer subjects who had all third molars removed had a PD 4 mm on the distal of their mandibular second molars after surgery, compared with those retaining at least 1 mandibular third molar (20% vs 69%, respectively, P=.001). The number of PDs 4 mm in the mandible was less after Surgery if all third molars had been removed (1.4% vs 6.6%, respectively).