A Comparison of Cone-Beam Computed Tomography and Direct Measurement in the Examination of the Mandibular Canal and Adjacent Structures

IntroductionThe purpose of this investigation was to assess the ability of cone-beam computed tomography (CBCT) scanning to measure distances from the apices of selected posterior teeth to the mandibular canal. Measurements were taken from the apices of all posterior teeth that were superior to the mandibular canal.MethodsA pilot study was performed to determine the scanning parameters that produced the most diagnostic image and the best dissection technique. Twelve human hemimandibles with posterior teeth were scanned at .20 voxels on an I-CAT Classic CBCT device (Imaging Sciences International, Hatfield, PA), and the scans were exported in Digital Imaging and Communications in Medicine (DICOM) format. The scans were examined in InVivo Dental software (Anatomage, San Jose, CA), and measurements were taken from the apex of each root along its long axis to the upper portion of the mandibular canal. The specimens were dissected under a dental operating microscope, and analogous direct measurements were taken with a Boley gauge. All measurements were taken in triplicate at least 1 week apart by one individual (TSK). The results were averaged and the data separated into matching pairs for statistical analysis.ResultsThere was no statistical difference (α = .05) between the methods of measurement according to the Wilcoxon matched pairs test (p = 0.676). For the anatomic measurements, the intra-rater correlation coefficient (ICC) was .980 and for the CBCT it was .949, indicating that both methods were highly reproducible. Both measurement methods were highly predictive of and highly correlated to each other according to regression and correlation analysis, respectively.ConclusionsBased on the results of this study, the I-CAT Classic can be used to measure distances from the apices of the posterior teeth to the mandibular canal as accurately as direct anatomic dissection.