Accuracy of assessing the mandibular canal on cone-beam computed tomography: a validation study.

To establish the accuracy of cone-beam computed tomographic (CBCT) views in determining the position and diameter of the mandibular canal. Two freshly frozen cadaver heads, 1 dentate and 1 edentate, were used to acquire CBCT scans. Measurements on cross-sectional CBCT images were compared with measurements on digitized histologic sections of the same regions in the mandibles. The Student t test was used for statistical analysis. Comparing CBCT with histologic measurements showed that the position of the mandibular canal differed up to 0.47 mm (standard deviation, 0.29 mm). Mandibular canal diameters were up to 22.8% smaller in the CBCT planes. For the dentate jaw, these differences were statistically significant. To be safe, when assessing the mandibular canal position on CBCT views, a 0.76-mm deviation should be taken into account. Because the diameter of the mandibular canal is displayed smaller, an enlargement by 0.74 mm is recommended.