Labio-lingual root control of lower anterior teeth and canines obtained by active and passive self-ligating brackets

Abstract

To investigate the torque capabilities of passive and active self-ligating (SL) brackets on mandibular incisors and canines using three-dimensional (3D) imaging analysis. Two types of SL bracket systems were analyzed: a passive and an active. Both brackets had a 0.022 × 0.028-inch slot size. Treatment protocol and wire sequences were followed as recommended by the manufacturers. Twenty-six patients were included in the passive group and 20 were included in the active group; all received pretreatment and posttreatment cone-beam computed tomography (CBCT) scanning. Based on the CBCT scans, a customized 3D analysis was developed to assess labiolingual inclination of the roots of mandibular canines and incisors with respect to the occlusal plane before and after treatment. Following treatment, a statistically significant labiolingual proclination of the teeth was seen in both groups. Moreover, in both SL systems the roots exhibited a large variation in labiolingual inclination between adjacent teeth even after treatment. A significant proclination was seen for the mandibular front teeth; the claimed third-order torque control of SL systems could not be demonstrated. Therefore, a considerable play between the wire and the brackets could be hypothesized, even more in relation to the passive than the active SL brackets.