Influence of CBCT device, voxel size, and segmentation software on the accuracy of tooth volume measurements

This study aimed to assess the influence of cone-beam computed tomography (CBCT) device type, voxel resolution, and segmentation software on the accuracy of tooth volume measurements.

Thirty extracted single-rooted human incisor teeth were included. Physical volumes were determined using the Archimedes water displacement method (WDM) as the gold standard. Each tooth was scanned using two CBCT devices (Planmeca Promax 3D-Mid and NewTom 5G-XL) at two voxel sizes (0.1-mm and 0.2-mm). Segmentation was performed using two semi-automatic software programs: 3D Slicer and ITK-SNAP. Volumetric deviations from WDM were statistically analyzed using repeated-measures ANOVA, with the significance level set at p < 0.05.

Although the differences between the two CBCT devices (p = 0.431) and voxel sizes (p = 0.070) were not statistically significant, a trend toward improved volumetric accuracy was noted with the Planmeca Promax 3D-Mid device and the 0.1 mm voxel size. In contrast, a statistically significant difference was found between the segmentation programs (p < 0.001). ITK-SNAP consistently produced higher volume deviations compared to both 3D Slicer and the gold-standard WDM. The most accurate results were achieved using the Planmeca Promax 3D-Mid device, a 0.1 mm voxel size, and the 3D Slicer software, with no statistically significant deviation from WDM (p = 0.467).

CBCT device selection and voxel size (0.1-mm vs. 0.2-mm) did not significantly affect volumetric accuracy in single-rooted incisor teeth. However, the choice of segmentation software played a critical role, with 3D Slicer providing measurements closest to the gold standard. These findings highlight the importance of software selection in CBCT-based volumetric measurements for dental applications, though the results may be limited to teeth with similar anatomical complexity (e.g., single-rooted incisors).