Detection of apical root resorption after orthodontic treatment by using panoramic radiography and cone-beam computed tomography of super-high resolution

Introduction: Apical root resorption is an adverse side effect of orthodontic treatment. We compared panoramic radiography (OPT) with cone-beam computed tomography (CBCT) in evaluating orthodontically induced apical root resorption. Methods: The study sample comprised 275 teeth in 22 patients near the end of orthodontic treatment with fixed appliances. Two calibrated examiners assessed blindly the presence or absence and the severity of apical root resorption on the OPT images after treatment and the corresponding reconstructed CBCT images. Resorption was evaluated as no, mild, moderate, severe, and extreme. Results: On the OPT images, 17 teeth (6.2%) could not be evaluated. Statistically significant differences were found between the 2 methods: 56.5% and 31% of the teeth showed no resorption by OPT and CBCT, respectively; 33.5% and 49% of the teeth showed mild resorption, whereas 8% and 19% showed moderate resorption by OPT and CBCT, respectively. Severe resorption was found in only 2 teeth by CBCT. Conclusions: Apical root resorption after orthodontic tooth movement is underestimated when evaluated on OPT. CBCT might be a useful complementary diagnostic method to conventional radiography, to be applied when a decision on continuation or modification of the orthodontic treatment is necessary because of orthodontically induced root resorption. (Am J Orthod Dentofacial Orthop 2009; 135:434-7)