Maxillary and mandibular canines’ torque expression during retraction using 0.022” Roth prescription brackets

Abstract

Background: In extraction cases, canine torque is of primary importance. Failure to maintain the root within the cancellous bone predisposes to root resorption and periodontal breakdown. Positive torque in the bracket or wire may prevent the proximity of the root and cortical bone as well as the subsequent side effects. Objective:The aim of this study was to evaluate the torque control provided by 0.022" Roth prescription brackets during canine retraction with sliding mechanics. Materials and methods:Twenty-one patients (19.2 ± 2.7 years) with various malocclusions involving canine retraction were included in the trial. Cone beam computer tomography was acquired before and six months after the start of canine retraction. The change in canine torque was calculated from the pre-and post-retraction 3-dimensional images. Torque was measured for maxillary and mandibular canines as the angle between the canine's long axis and the mid-sagittal plane. The paired t-test was used to evaluate the change in torque.Results: Statistically significant increase in the angle occurred for the maxillary (3.088±5.627°) and mandibular (2.971±5.427°) canines. Conclusion:Canines could express labial crown inclination during retraction despite the absence of a positive built-in bracket torque.