Association of Ramus Relationship of Impacted Mandibular Third Molar with the Prevalence of Radiolucencies in the Adjacent Second Molar in the Right Versus Left Mandible

Abstract

Background: Impacted mandibular third molars are common and may predispose the adjacent mandibular second molar to radiographically detectable pathology, including periapical changes, pericoronal radiolucency, distal caries, and external root resorption. The extent to which ramus relationship modifies these risks, and whether associations differ between left and right mandible, remains incompletely characterized. Objective: To determine the association between Pell–Gregory ramus relationship of impacted mandibular third molars and the prevalence of radiographic pathologies in the adjacent mandibular second molar, comparing left versus right mandible. Methods: A retrospective cross-sectional analysis of panoramic radiographs was conducted (August 2024–August 2025) in adults aged ≥21 years. Eligible quadrants contained an impacted mandibular third molar and adjacent second molar. Ramus relationship was classified as Class I–III and second molar outcomes were recorded dichotomously. Side-specific associations were evaluated using chi-square or Fisher’s exact tests, with unadjusted odds ratios (ORs) and 95% confidence intervals (CIs) computed using Class I as reference. Results: On the left side, ramus relationship was not significantly associated with periapical radiolucency (p=0.795), pericoronal radiolucency (p=0.370), distal caries (p=0.287), or external root resorption (p=0.071). On the right side, associations were non-significant for periapical radiolucency (p=0.159), pericoronal radiolucency (p=0.197), and distal caries (p=0.222), while external root resorption showed a significant association (p=0.024), with higher prevalence in the most space-limited class. Conclusion: Ramus relationship did not significantly influence most adjacent second molar pathologies on either side, but a right-sided association with external root resorption was observed, warranting confirmatory studies using larger samples and enhanced imaging.