Second Mandibular Molar Roots in Relation to Mandibular Canal in Cone Beam Computed Tomography

Trauma to the mandibular canal during endodontic treatment can cause permanent damage to the inferior alveolar nerve, ranging from sensory disturbances to tissue necrosis. The roots of the second molar are closest to the mandibular canal, which significantly increases the risk of iatrogenic injuries. The aim of the study was to evaluate the relationship of the roots of mandibular second molar to the mandibular canal in cone beam computed tomography (CBCT). A cross-sectional study was conducted including 200 patients, the analysed CBCT examinations were made for other diagnostic needs. A total of 375 teeth were evaluated in the research, including 193 left and 182 right second molars. The most common distance from the mandibular second molar to the mandibular canal was 1.01–3.00 mm, direct contact with the canal was observed in up to 21.1 % of cases. Penetration of the root apex into the mandibular canal was observed in up to 1.2 %. The most common location of the canal to the root apex was apical (84.2–97.5 %). When performing root canal treatment, the dentist must be especially careful to avoid iatrogenic injuries to the alveolar nerve, which can significantly reduce the patient’s quality of life.