External apical root resorption in patients treated with conventional and self-ligating brackets

Introduction: Our aim was to comparatively investigate the amount of external apical root resorption (EARR) between conventional and passive self-ligating brackets. Methods: Ninety-six patients were selected from a pool of patients satisfying the following inclusion criteria: no evidence of resorption on the pretreatment panoramic radiographs; no contributing history of trauma; no dilacerations of lateral incisor roots, maxillary anodontia, and impacted canines; complete root formation at the start of treatment; intact and caries-free maxillary incisors; and no endodontically treated incisors. Patients received treatment with either a passive self-ligating bracket system or a conventional edgewise appliance, both with a 0.022-in slot. EARR of the maxillary incisors was evaluated on panoramic radiographs, taken before and after orthodontic treatment measured in millimeters. Distortion of measurements caused by panoramic radiographs was investigated by using a calibrated periodontal probe attached to the lateral incisor, and the extent of magnification was estimated to be 14%. Statistical comparisons of EARR between appliance type, age, sex, extraction treatment, and duration of treatment were investigated with univariate and multivariate regression modeling. Results: Overall, no difference was found in the amount of EARR between appliance systems. Age, sex, and extraction treatment were not reliable predictors of EARR, but a positive association between EARR and duration of treatment was observed. Conclusions: No difference should be expected for root resorption between conventional and passive self-ligating brackets. ( Am J Orthod Dentofacial Orthop 2008; 134: 646-51)