Diagnostic accuracy of small volume cone beam computed tomography and intraoral periapical radiography for the detection of simulated external inflammatory root resorption.

AIM To compare in an ex vivo model the ability of digital intraoral radiography and cone beam computed tomography (CBCT) to detect simulated external inflammatory root resorption lesions, and to investigate the effect of altering the degree of rotation of the CBCT scanners X-ray source and imaging detector on the ability to detect the same lesions. METHODOLOGY Small and large simulated external inflammatory resorption (EIR) lesions were created on the roots of 10 mandibular incisor teeth from three human mandibles. Small volume CBCT scans with 180° and 360° of X-ray source rotation and periapical radiographs, using a digital photostimulable phosphor plate system, were taken prior to and after the creation of the EIR lesions. The teeth were relocated in their original sockets during imaging. Receiver operator characteristic (ROC) analysis and kappa tests of the reproducibility of the imaging techniques were carried out and sensitivity, specificity, positive and negative predictive values (PPV and NPV) were also determined for each technique. RESULTS The overall area under the ROC curve (Az value) for intraoral radiography was 0.665, compared to Az values of 0.984 and 0.990 for 180° and 360° CBCT, respectively (P<0.001). The sensitivity and specificity of 180° and 360° CBCT were significantly better than intraoral radiography (P<0.001). CBCT, regardless of the degree of rotation, had superior NPVs (P<0.01) and PPVs (P<0.001) to periapical radiography. The intra- and inter-examiner agreement was significantly better for CBCT than it was for intraoral radiography (P<0.001). The ability of small volume CBCT to detect simulated EIR was the same regardless of whether 180° or 360° scans were taken. Examiners were significantly better able to identify the exact location of the artificial resorption lesions with CBCT than they were with periapical radiographs (P<0.001). CONCLUSION CBCT is a reliable and valid method of detecting simulated EIR and performs significantly better than intraoral periapical radiography. Small volume CBCT operating with 360° of rotation of the X-ray source and detector is no better at detecting small, artificially created EIR cavities than the same device operating with 180° of rotation.