In vitro diagnostic accuracy of cone-beam computed tomography with variable gamma values for detection of vertical root fractures in teeth with prefabricated metal posts

BACKGROUND: Cone-beam computed tomography (CBCT) has the highest sensitivity and specificity for the detection of vertical root fractures (VRFs). This study aimed to compare the diagnostic accuracy of CBCT with different gamma values for the detection of VRFs. MATERIALS AND METHODS: In this in vitro, experimental study, multiplanar CBCT scans were obtained from 61 extracted premolars with prefabricated titanium posts using NewTom CBCT scanner. Next, VRFs were artificially induced in all teeth with a mallet, and the teeth underwent CBCT with three different gamma values. The images were evaluated by two observers twice with a 2-week interval for the presence/absence of VRFs. Data were analyzed using the kappa coefficient, McNemar test, and Chi-square test. The sensitivity, specificity, and overall accuracy of CBCT with different gamma values for the detection of VRFs were assessed by receiver operating characteristic curve. The level of significance was lesser than 0.05 (P < 0.05). RESULTS: Changing the gamma value did not change the sensitivity, specificity, or accuracy of CBCT for the detection of VRFs. No significant difference was noted between the two observers in the detection of VRFs on CBCT scans taken with different gamma grades. The inter- and intra-observer agreement were excellent for all gamma grades. CONCLUSION: Any gamma value preferred by the observer can be used for the detection of VRFs on CBCT scans.