Accuracy of Different Imaging CBCT Systems for the Detection of Natural External Radicular Resorption Cavities: An Ex Vivo Study.

OBJECTIVE: The aim of this study was to compare the sensitivity and specificity of 3 different systems of cone-beam computed tomography (CBCT) in the detection of natural external root resorption (ERR) cavities using microtomography as the gold standard. METHOD: A sample of 126 ex vivo teeth were submitted to a microtomography examination to verify the presence/absence of ERR cavities. Then, they were divided into the control group: 85 teeth that did not present with an ERR cavity; and experimental group: 41 teeth that presented with 1 or more ERR cavities. The size of the natural ERR cavities varied from 2.46 mm3 to 3.11 mm3, which corresponded to cavities of 1.67 mm and 1.81 mm in diameter, respectively. The teeth were placed on a dry human mandible for scanning in each of the 3 protocols with different voxel sizes: 0.25 mm, 0.20 mm, and 0.166 mm. RESULTS: The accuracy of the 3 protocols evaluated in this study are listed in decreasing order: 60.3% for a voxel size of 0.20 mm, 56.7% for a voxel size of 0.166 mm, and 46.7% for a voxel size of 0.25 mm; these are smaller values than previous studies have obtained using artificial ERR cavities. Statistically significant results were not found among the 3 CBCT protocols that were used (P > .05), and the receiver operating characteristic curve shows the small differences found between the protocols. CONCLUSION: The results indicate that CBCT presents, for natural ERR, lower sensitivity and specificity values than those detected in previous studies of artificial cavities. The results demonstrate that natural ERR is neither easily observed nor accurately located by CBCT, as previous studies using artificial ERR indicated.

Accuracy of Digital Periapical Radiography and Cone-beam Computed Tomography for Diagnosis of Natural and Simulated External Root Resorption.

INTRODUCTION: The aim of this study was to compare the sensitivity and specificity of digital periapical radiography and cone-beam computed tomographic (CBCT) imaging in the detection of natural and simulated external root resorptions (ERRs) with micro-computed tomographic (micro-CT) imaging as the reference standard. METHODS: One hundred twenty-six teeth were scanned using the SkyScan 1172 micro-CT scanner (Bruker microCT, Kontich, Belgium), and the images were evaluated using NRecon software (Bruker microCT). After micro-CT imaging, the teeth were divided into 3 groups: control, 42 teeth that did not present any ERR cavities; natural, 42 teeth that presented 1 or more ERR cavities; and artificial, 42 teeth without ERRs but perforations were created to simulate the cavities. Ortho-, mesio-, and distoradial digital periapical radiographs and CBCT images were obtained, and the images were evaluated by 2 double-blinded qualified radiologists. RESULTS: The sensitivities and specificities for the radiographic and tomographic methods were 78.18% and 97.27% and 59.52% and 97.62%, respectively. Within the individual groups, both methods had lower sensitivity and specificity for natural and artificial resorptions, and the differences were statistically significant. CONCLUSIONS: CBCT imaging was the best method for the detection of ERRs. Only 74.5% of natural ERR gaps were observed on the digital periapical radiographs and 94.5% on CBCT imaging; in the artificial group, this number increased to 81.8% and 100%, respectively. The configuration of the natural ERR gaps is different from those artificially simulated and is much more difficult to observe.