Association between impacted mandibular third molars and distal caries in second molars-A radiographic study

Abstract

Objective: The aim of this study was to evaluate the incidence of caries on distal aspect of mandibular second molars in patients with impacted mandibular third molars using cone beam computed tomography (CBCT) radiography and to identify its association with angular position and depth of the impacted mandibular third molars based on the classification by Pell and Gregory. Methods: Maxillofacial cone beam computed tomography scan records of 35 patients with impacted third molars presenting to the Department of Oral and Maxillofacial Surgery, Saveetha dental college and Hospital were collected and assessed. Using CBCT the radiographic angulation and depth of mandibular third molar impaction were determined and compared to determine the relationship with incidence of caries on the distal surface of the second molar. Data were checked using Sirona software, statistically analyzed and results obtained. Results: Mesioangular position was the most common type of impaction with a distribution of 56% among all the impactions. According to this study results, 45.7% cases showed caries on the distal aspect of mandibular second molars. The incidence of caries was highest with mesioangularly impacted third molars (62%). A majority of these mesioangular cases were Level A and Class I as per the Pell and Gregory classification. Conclusion: The prophylactic extraction of mesioangular impacted mandibular third molars is indicated if the angulation in CBCT is between 30° and 70° and is justified by the incidence of distal caries in the second molars.