Accuracy of In-vitro Tooth Volumetric Measurements from Cone-beam Computed Tomography

Introduction: The aims of this study were to determine the accuracy of volumetric measurements of teeth in vitro by cone-beam computed tomography (CBCT) and to analyze the factors affecting their volume measurements from the CBCT data.

Methods: We used a sample of CBCT-scanned (voxel sizes: 0.125, 0.20, 0.25, 0.30, and 0.40 mm) and laser-scanned crowns (n = 40) and roots (n = 32). The Tukey test was used to assess the differences between the CBCT-scan and the laser-scan volumes.

Results: There was a statistically significant difference between the laser-scan crown volume and each voxel size of CBCT-scan crown volume (P <0.05). CBCT-scan crown volumes at 0.30 and 0.40 mm were statistically significantly distinct from those at 0.125, 0.20, and 0.25 mm (P <0.05). There was a statistically significant difference between the laser-scan root volume and each voxel size of CBCT-scan root volume (P <0.05). The laser-scan root volume at 0.40 mm was statistically significantly distinct from the volumes at 0.125 and 0.20 mm (P <0.05). The in-vitro volume measurements from the CBCT scans were larger than those of the laser scans: from 21.73% to 43.92% in the crown halves, and from 18.27% to 41.58% in the root halves at the different voxel sizes.

Conclusions: With increasing voxel sizes during scanning, the volume measurements of teeth tended to be larger. The surface surrounding artifacts might lead to larger volumes.