Evaluation of the position of mandibular third molar hidden teeth and its effect on second adjacent molar teeth in panoramic radiography in patients referring to Birjand Dental School in 2018-19

Background and Aim: The third molar tooth lies with symptoms such as periodontal problems, caries, crowding, root resorption, cyst and tumor formation of the adjacent second molar. The purpose of this study was performed to evaluation of the position of mandibular third molar teeth and its effect on second adjacent molar teeth. Materials and Methods: Panoramic radiography were obtained from 264 patients with mandibular third molar hidden teeth referred to the Birjand School of Dentistry in 2018. The material and direction of their placement and the vertical position of the third molar tooth (based on the PELL & Gregory classification) and its placement angle (based on Winter classification) were determined. Also, the prevalence of distal caries, external root resorption, the amount of displacement, and the amount of inflammatory lesions and the cystic was examined in the adjacent second molar tooth. Data were analyzed using SPSS software (Version 19), and chi-square statistical test, p-values less than 0.05 were considered statistically significant. Results:  The data from this study showed that most of the wisdom hidden teeth were in Class B and III of Pell and Gregory classification, had Mesial angle based on Winter classification. In 20.8% of patients with caries, there was 3% root canal resorption and 1.1% displacement of the second molar tooth, while no cases of inflammatory and cystic lesions in the second molar tooth were found due to the hidden third molar tooth. The Mesial and horizontal angles of impacted wisdom teeth were associated with increased risk of caries and root resorption of the second molar. Also, Class Bchr('39')s third molar teeth increased caries in second molar teeth. Conclusion: Most pathological problems were observed in Mesial, horizontal, and class B impaction. According to the observed relationship, it seems that the angle and depth of the hidden third molar should be taken into account considered when deciding whether or not to extract it.