Comparison of active and passive self-ligating brackets in the treatment of class i crowding

Aim: The aim of this study to compare clinical effects of active and passive self-ligating brackets (SLB) used in treatments of Class I crowding cases, changes in axial inclination of maxillary anterior teeth and alveolar bone thickness through CBCT imaging method. Material and method: This study was carried out on 31 individuals having skeletal and dental Class I maloclussion. Patients were divided into two groups. The first group was applied BioPassive, the other group was applied BioQuick brackets, both with 0.022 inch slot. In both groups, cephalometric x-ray and CBCT records of patients were taken before treatment and 8 months after beginning of treatment. Digital orthodontic model records of patients were taken before treatment, 4 months and 8 months after beginning of treatment. Results: Irregularity index of mandible and maxilla decreased significantly in both groups. Both bracket systems displayed no levelling efficiency difference for mandible and maxilla. Transversal dimensions of maxillary and mandibular arches increased significantly but no difference was found between both groups. Anterior depth of maxillary arch decreased insignificantly in both groups. However there was statistically difference between two groups for decrease of anterior depth in maxilla. Anterior depth of mandibular arch increased significantly but no difference was found between both groups. In accordance with cephalometric x-ray analysis, a significant increase was determined for upper incisor inclinations and the difference between two groups is insignificant in terms of increase of upper incisor inclinations. Likewise, CBCT evaluations revealed a significant increase for upper incisor inclinations in two groups and no difference between two groups for upper incisor inclinations. In accordance with CBCT evaluations of anterior alveolar bone for maxilla, the coronal section of labial alveolar bone and the apical section of palatal alveolar bone decreased significantly in two groups but the difference between two groups was insignificant. Conclusion: There was no significant difference between two bracket systems for leveling efficiency and torque control of upper insicors. Desissens might occur in anterior region of alveolar bone that should be taken into account when a non-extraction treatment plan prefered with SLB and wide archwire combinations in severe crowding cases. Key words: Self-ligating; CBCT; Digital model