External root resorption of second molars due to impacted third molars.

Background: The current study attempts to assess the impact of third molar impaction on external root resorption (ERR) of the adjacent second molars. We aimed to determine the prevalence, severity, and associated factors with ERR in a sample of panoramic radiographs. Material and Methods: A retrospective cross-sectional study was carried out at teaching hospital. We reviewed panoramic radiographs from September 2021 to September 2024, selecting images with second and third molars in patients over 16 years old and impacted third molars. ERR was analyzed with respect to patient age and sex. The presence of symptoms, site and severity of root resorption, relationship to angulation, and depth of impaction were also recorded. Results: A total of 750 panoramic radiographs were examined, and ERR was observed in 32 cases (4.30%). ERR was slightly more common in males (62.5%) than in females (37.5%), but the difference was not statistically significant. The maximum number of ERR cases was found in the age group of 16-25 years (68.7%). Most classification of ERR was mild (71.8%). Mesioangular impacted third molars were associated with 65.6% of resorption cases and position C third molars were associated with 90.6% of resorption cases. The middle third of the root was the most common site of ERR (59.3%). Conclusions: ERR of second molars was relatively more common among patients with impacted third molars. Associations were significant for angulation (mesioangular), depth of impaction, and ERR. Hence, a question arises in assessing the amount of risk associated with its impaction in panoramic radiographic imaging.