Assessing the influence of third molar classification on the risk of caries in adjacent teeth

Background/aim: This study aimed to evaluate the relationship between the impaction level and angulation of third molars and the incidence of caries in the adjacent second molars. Materials and methods: A total of 690 panoramic radiographs obtained from patients at Ankara Yıldırım Beyazıt University between May 2022 and January 2024 were retrospectively analyzed. Third molars were classified based on their eruption status using the Pell and Gregory classification (levels A, B, and C), and angulation (mesioangular, distoangular, vertical, horizontal, and inverted). The presence of caries in adjacent second molars was assessed using the international caries detection and assessment system/international caries classification and management system. The association between third molar position and the presence of caries in second molars was statistically evaluated. Results: Among the 1164 third molars assessed, 52.9% were located in the mandible, and 75.2% were in a vertical position. Carious lesions were identified in 22.3% of third molars. Adjacent mandibular second molars had caries in 53.2% of cases, compared to 35.6% in the maxilla. According to the Pell and Gregory classification, class I, level A mandibular third molars were associated with the highest incidence of caries in adjacent second molars (159 out of 616). Furthermore, when only impacted teeth were considered, mesioangular impactions were associated with the highest prevalence of caries, observed in 41.1% of cases (51 out of 123). Conclusion: The findings indicate that the position and angulation of third molars play an important role in the risk of caries development in adjacent second molars. In the mandible, level A third molars in vertical (65.2%) and mesioangular (41.1%) positions had the greatest risk for caries development in adjacent second molars, whereas in the maxilla, the highest risk was found in vertical (47.3%) and mesioangular (25.7%) impactions. These results underscore the importance of early clinical evaluation and the implementation of preventive strategies to minimize caries risk in second molars associated with impacted third molars.