Method: CBCT exams were taken of 12 dried human mandibles with voxel dimensions of 0.2, 0.3 and 0.4 mm using the iCat Cone Beam 3-D Dental Imaging System. The thickness of the buccal and lingual bone plates of teeth was measured on an axial section passing 12 mm above the right mental foramen. Natural buccal bone dehiscence was measured in cross sections passing through the center of each teeth and directly on the mandibles. Images were measured by two examiners. Accuracy was evaluated using t tests. Intra-examiner and intra-examiner reproducibility was assessed using the paired t-test and independent t-test, respectively (p<0.05).
Result: For the thickness of bone plates, high inter-examiner reproducibility was observed for the three protocols analyzed. Intra-examiner reproducibility was very good, with the exception of some regions of the anterior teeth, which exhibited statistically significant differences regardless of the voxel dimensions. A high accuracy for measurements of dehiscence was observed. The protocol of 0.4 mm voxel had a greater number of errors compared to protocols with 0.3 and 0.2 mm voxel, showing a trend in higher precision with smaller voxel.
Conclusion: Measurements of bone plate thickness and level on CBCT images demonstrated good precision for voxel dimensions of 0.2 and 0.3mm. The reproducibility of measurements for the mandibular incisors was smaller compared to posterior teeth.