Evaluation of validity of cone beam CT (CBCT) measurements compared to direct method on human dry mandibles

Introduction: Cone beam computed tomography (CBCT) has its wide range of uses in dentistry most commonly as an aid in preoperative planning of dental implant treatment. However, in order to determine the best application of CBCT in dentistry, it is necessary to analyze the accuracy of data obtained related to distance measurements. The present in-vitro study was undertaken to evaluate the accuracy of radiographic linear measurements on CBCT images by comparing them to direct measurements in human dry mandibles. Materials and methods: Ten human dentulous dry mandibles were selected for the study. Four anatomical sites (Site A, B, C, and D) with two anatomical reference points for each site were selected on dry mandibles for measurement. The reference points were made as 3 mm depressions on the mandible with Marathon micromotor hand piece and diamond bur. These depressions were filled by guttapercha. All the selected mandibles were scanned using Sorodex Cranex 3Dx CBCT Machine. After the CBCT scan was obtained, the direct measurements at each site were recorded using digital vernier calipers with an accuracy of 0.01mm. Results: Comparison of CBCT measurements with direct measurements at 4 anatomical sites revealed no statistical difference (p value >0.05). Correlation of CBCT measurements with direct measurements revealed strong correlation at site site A (0.965), site B (r=0.899), D (r=0.975) and moderate correlation at site C (r=0.571). Conclusion: According to present study, CBCT technique can be recommended for linear measurements in the mandible.