Third Molar Periodontal Pathology in the Third Decade and Periodontal Pathogens

Abstract

Statement of the Problem: Increased periodontal probing depth in the 3rd molar region is common for young patients. High levels of pathogens detected on the distal of second molars at baseline might predict periodontal pathology. This study assessed the association between follow-up periodontal probing depths in the 3rd molar region and the baseline levels of periodontal pathogens for patients in a longitudinal trial. Patients and Methods: Data derived from healthy patients with four asymptomatic 3rd molars. Panoramic radiographs were analyzed for 3rd molar angulation as compared to the long axis of the 2nd molar (mesial/ horizontal 25 degrees) and eruption to the occlusal plane. Full mouth periodontal probing (PD) was conducted at follow-up. The baseline levels of bacteria were determined using whole chromosomal DNA probes and DNA checkerboard hybridization. Detected bacteria were grouped into “orange” and “red” complexes according to Socransky. A level of “orange” and “red” complex microorganisms at 105 was considered clinically important. Method of Data Analysis: The follow-up PD in the 3rd molar region, the distal of 2nd or around 3rd molars, were compared to baseline levels of “orange” and “red” complex microorganisms. Level of significance for Chi2 statistics was set at P 0.05. Results: Data from 240 patients were available. Median follow-up was 2.2 y (IQ 2.0, 3.7 y). Baseline median age was 25.9 y (IQ 22, 32.8 y). More were female, 53%, and Caucasian, 82%. At follow-up 12% maxillary mesial/horizontal impacted 3rd and 28% mandibular 3rd molars had a PD 4 mm. Similarly affected were 11% of the maxillary vertical/distal impacted 3rd and 32% of the mandibular 3rd molars. Only 11% maxillary erupted 3rd molars had a PD 4 mm, but 51% of the mandibular erupted 3rd molars were affected. If a patient had a PD 4 mm at follow-up and baseline periodontal pathogens 105, the pathogens 105 were likely to be detected in the same quadrant, 45 of 51 (88%). With a PD 4 mm in the maxilla at follow-up, 43% of patients had baseline pathogen levels detected in the same quadrant 105, as compared to 30% with follow-up PD 4 mm. For the mandible a PD 4 mm in the 3rd molar region at follow-up was associated more often with baseline quadrant levels of pathogens 105, compared to 3rd molar PD 4 mm, 29% vs. 26%. Differences were not statistically significant. Perhaps the short time interval from baseline to follow-up did not allow for high levels of pathogens at baseline to influence follow-up PD. Of the 3rd molar regions in the maxilla with 105 pathogens at baseline, 22% had PD 4 mm at follow-up. In the mandible with 105 pathogens at baseline, 63% had PD 4 mm at follow-up. Conclusion: If pathogens 105 are detected with increased PD, both are likely in the same quadrant. Patients continue to be followed to determine how often baseline levels of pathogens predict increased PD.