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.