Root resorption of maxillary incisors after traction of unilateral vs bilateral impacted canines with reinforced anchorage

Introduction: The aim of this study was to compare the root resorption (RR) of maxillary incisors after traction of unilateral vs bilateral impacted canines with reinforced anchorage. Methods: This retrospective longitudinal study included 60 cone-beam computed tomography scans of patients with maxillary impacted canines: 30 scans taken before and 30 taken after orthodontic traction with nickel-titanium coil springs. Two groups were formed according to the impaction condition: 15 with unilateral maxillary impacted canines and 15 with bilateral maxillary impacted canines. Three trained orthodontists made the measurements. Demographic variables, occlusal characteristics, skeletal class, and measurements related to canine impaction were collected from the clinical history, dental models, and radiographs of each patient. RR (mm and mm²) for each maxillary incisor was measured in 3 dimensions. Independent t or Mann-Whitney U tests were used, depending on data normality. Multiple linear regression analyses were used to evaluate the influence of all variables (predictors) on RR (α = 0.05). Results: RR did not show significant differences between groups in any section (P > 0.05). No subject had RR greater than 2 mm or 5 mm². The specific influence of some predictor variables varied depending on the type of maxillary incisor. Conclusions: RR of maxillary incisors after traction of unilateral vs bilateral impacted canines with reinforced anchorage was similar and is not a risk to the integrity of the maxillary incisor root.