Comparison between Conventional Orthopantomograph and Three Dimensional Reconstructed OPG from Cone Beam Computed Tomography in Evaluation of Root Resorption during Orthodontic Treatment

Introduction: Radicular resorption is an unwanted side effect of orthodontic therapy. Aim: The aim of this study was to compare between two radiographic methods in detection of root resorption induced by orthodontic treatment, by comparing panoramic radiographic images (OPG) with cone-beam computed tomography volumes (CBCT) in assessing radicular resorption encouraged by orthodontic treatments. Methods: The sample of this study consisted of 469 teeth in 20 individuals after the completion of leveling and alignment phase of orthodontic therapy with fixed appliances. This study examined & tested the existence or nonexistence and the degree of radicular reabsorption on the OPG and the corresponding reconstructed 3D CBCT volumes. Radicular resorption was assessed as grade 0 (no resorption), grade 1 (mild resorption), grade 2 (moderate resorption), grade 3 (severe resorption) and grade 4 (extreme resorption). Results: assessment of OPG radiographs showed that the evaluation of 12 teeth was not possible. There were statistically significant differences found between OPG and CBCT: 165 and 87 teeth revealed no radicular resorption by OPG and CBCT volumes, respectively; 237 and 292 teeth revealed mild root resorption, while 54 and 79 revealed moderate resorption by OPG and CBCT volumes, respectively. Furthermore, 3 teeth evaluated to have grade 3 radicular resorption (severe resorption) when evaluated by OPG, while 10 teeth were assessed to have severe resorption with CBCT. Conclusion: Radicular resorption during and after orthodontic movement of teeth is underrated when assessed by OPG. CBCT may be a valuable complemental analytic technique to formal radiology, in order to be used when a choice on continuance or adjustment of the orthodontic therapy is needed due to root resorption induced by orthodontic treatment.