Does Darkening of Roots or Loss of White Line on Panoramic Radiographs Pose a Risk for Inferior Alveolar Nerve Damage? A CBCT Evaluation

Abstract

Introduction: Surgical removal of impacted mandibular third molars may cause dysesthesia due to damage to the inferior alveolar nerve (IAN), and the risk increases when there is direct contact between the nerve and the tooth root. An accurate preoperative radiographic examination using Cone beam computed tomography (CBCT) provides precise information pertaining the relationship between the third molar roots and the inferior alveolar canal. Aim & Objective: This study was intended to correlate the two panoramic radiographic findings in predicting the absence of corticalization between the mandibular canal and the third molar on cone beam computed tomography (CBCT) images and to evaluate the possibility of inferior alveolar nerve (IAN) injury. Materials and Methods: The study was conducted on 60 patients, who were divided into two groups of 30 each. Group I included 30 patients whose panoramic radiographic findings showed darkening of the root of impacted mandibular third molar. Group II included 30 patients whose panoramic radiographic findings showed interruption of white line of mandibular canal. The patients whose panoramic radiographic findings showed darkening of the root or interruption in the white line of the canal were subjected to CBCT examination. Surgical removal of impacted mandibular third molar in all the patients was performed under local anesthesia (LA). Evaluation for any nerve injury was performed and recorded as presence or absence of paresthesia at regular postoperatively. Results: The results of this study showed that 46.7% patients had absence of cortication in Group I (darkening of roots), whereas it was absent in 33.3% of patients in Group II (loss of white lines). Presence of cortication was seen in 53.3% of patients in Group I when compared to 66.7% in Group II. The difference between the groups was not found to be statistically significant. Conclusion: Darkening of roots and interruption of white line observed on panoramic radiographs, both as isolated findings and in association, were effective in determining the risk relationship between the tooth roots and the mandibular canal necessitating CBCT evaluation.

Keywords

• Cone beam computed tomography (CBCT)
• inferior alveolar nerve
• panoramic radiograph