Detection of Vertical Root Fractures by Using Cone Beam Computed Tomography with Variable Voxel Sizes in an In Vitro Model

Introduction: The aim of this study was to compare the diagnostic accuracy of cone beam computed tomography (CBCT) scans with different voxel resolutions in the detection of simulated vertical root fracture (VRF). Methods: Sixty teeth, 30 with root fractures and 30 without, were examined through i-CAT tomography at 4 different voxel resolutions (0.125, 0.2, 0.3, 0.4 mm). Three observers scored the presence of VRF in all modalities. Sensitivity, specificity, likelihood ratio, and accuracy were calculated for each modality. Results: Chi-square statistical analysis showed no significant difference among the resolutions or observers. However, positive likelihood ratio values of 24.5 for a 0.125-mm voxel, 24.25 for a 0.2-mm voxel, 13.2 for a 0.3-mm voxel, and 13 for a 0.4-mm voxel were found. Accuracy results confirmed the likelihood ratios as 0.97, 0.96, 0.93, and 0.92, respectively. Conclusions: CBCT scans were reliable in detecting simulated VRF, and a 0.2-mm voxel was the best protocol, considering the lower x-ray exposure and good diagnostic performance. (J Endod 2011;37:75-79)