Accuracy of in-vitro tooth volumetric measurements from cone-beam computed tomography

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.

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.

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.

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