Root and alveolar bone changes in first premolars adjacent to the traction of buccal versus palatal maxillary impacted canines

Objective To compare the root and alveolar bone changes in first premolars adjacent to the orthodontic traction of buccal versus palatal maxillary impacted canines (MIC). Materials and methods Before and after traction, cone beam tomographic computed (CBCTs) of 25 subjects with unilateral/bilateral MIC were included in this follow-up and retrospective study. Thirty-six first premolars were divided into 2 groups, buccal (n = 15) or palatal (n = 21) MIC, and the tomographic images were evaluated before and after orthodontic traction. Root changes in length and area were measured in sagittal, coronal and axial sections. Dimensions of alveolar bone were evaluated in coronal sections. Intergroup and intragroup comparisons were performed using t or Mann-Whitney U tests. Multiple linear regressions analyses were used to evaluate the influence of all predictor variables on root and alveolar bone changes (P<0.05). Results Root and alveolar bone changes produced by orthodontic traction were not significant between groups. Root changes were smaller than 1 mm (length) and 2.51 mm² (area). Alveolar bone changes between buccal and palatal MIC groups ranged from 0.13 mm to 1.69 mm Furthermore, the multivariate analysis showed no significant influence of the impaction condition (buccal or palatal) on root change. Nevertheless, some different predictor variables of the MIC influence these changes. In the alveolar bone, the maximum upper alveolar width (MUAW) is the most affected by the traction of the MIC. Conclusions Orthodontic traction of buccal vs palatal MIC produces similar resorptive and appositional root and alveolar bone changes in the adjacent first premolars, without clinical relevance.