Department of Orthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, China.
Orthod Craniofac Res. 2020 Nov;23(4):509-516. doi: 10.1111/ocr.12403. Epub 2020 Jul 9.
Appropriate torque expression contributes to ideal treatment outcomes both clinically and aesthetically. Whether active and passive self-ligating brackets (SLBs) have different torque-control capability in vivo has never been reported. The purpose of present study was to explore whether there was difference in torque expression in active and passive SLBs.
In this retrospective study, 225 patients with four first premolar extractions were enrolled. For each patient, the digital lateral cephalometric radiographs were taken before and after treatment.
The study consisted of 2 groups: 111 subjects were treated with passive SLBs (Damon Q, Ormco) and 114 subjects with active SLBs (Empower 2, American Orthodontics). Measurements to determine skeletal changes and incisor inclination were obtained from cephalometric tracings using Dolphin software (version 11.8, USA). Comparisons in both groups and intergroups were compared using t tests and chi-square test.
Significant differences in the variation of U1-SN(°), U1-NA(°), L1-NB(°) and L1-FH(°) were found between two groups. More labially inclined maxillary incisors were found in active SLB group, while more labially inclined mandibular incisors were observed in passive SLB group.
With the present prescription set in the two brackets, active SLBs achieved more proclined maxillary incisors and retroclined mandibular incisors. Clinicians should take torque expression of brackets into consideration during orthodontic treatment.
适当的转矩表达有助于临床和美学上达到理想的治疗效果。主动自锁托槽（SLB）和被动自锁托槽在体内是否具有不同的转矩控制能力尚未见报道。本研究旨在探讨主动自锁托槽和被动自锁托槽在转矩表达上是否存在差异。
在这项回顾性研究中，共纳入了 225 名接受四颗第一前磨牙拔牙的患者。每位患者在治疗前后均拍摄数字化侧位头颅侧位片。
研究包括两组：111 例患者接受被动自锁托槽（Damon Q，Ormco）治疗，114 例患者接受主动自锁托槽（Empower 2，美国 Orthodontics）治疗。使用 Dolphin 软件（美国版 11.8）从头颅侧位片上的头影测量获得确定骨骼变化和切牙倾斜度的测量值。使用 t 检验和卡方检验对两组之间和组间进行比较。
两组之间 U1-SN（°）、U1-NA（°）、L1-NB（°）和 L1-FH（°）的变化存在显著差异。主动自锁托槽组的上颌切牙更向唇侧倾斜，而被动自锁托槽组的下颌切牙更向唇侧倾斜。
在两种托槽的现有处方设置下，主动自锁托槽使上颌切牙更前倾，下颌切牙更后倾。临床医生在正畸治疗中应考虑托槽的转矩表达。
