A comparative study of cone-beam computed tomography and conventional panoramic radiography in assessing the topographic relationship between the mandibular canal and impacted third molars

Objective. To evaluate the diagnostic accuracy of cone-beam CT compared with panoramic images in predicting neurovascular bundle exposure during extraction of impacted mandibular third molars. Study design. Cone-beam CT and panoramic images of 142 impacted mandibular third molars were prospectively evaluated to assess tooth relationship to the mandibular canal. These interpretations were then correlated with intraoperative findings. The sensitivity and specificity of the 2 modalities in predicting neurovascular bundle exposure at extraction were calculated and compared. The diagnostic criterion for panoramic images was defined using multivariate logistic regression analysis. Results. In predicting the exposure, the sensitivity and specificity were 93% and 77% for cone-beam CT, and 70% and 63% for panoramic images, respectively. Cone-beam CT was significantly superior to panoramic images in both sensitivity and specificity. Conclusion. Cone-beam CT was significantly superior to panoramic images in predicting neurovascular bundle exposure during extraction of impacted mandibular third molar teeth.