Zablocki Heather L, McNamara James A, Franchi Lorenzo, Baccetti Tiziano
Graduate Orthodontic Program, Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor 48109-1078, Mich, USA.
Am J Orthod Dentofacial Orthop. 2008 Jun;133(6):852-60. doi: 10.1016/j.ajodo.2006.07.031.
The transpalatal arch (TPA) can be used as an adjunct during orthodontic treatment to help control the movement of the maxillary first molars in 3 dimensions, including producing molar rotation and uprighting, maintaining transverse dimensions posteriorly during treatment, and maintaining leeway spaces during the transition of the dentition. The purpose of this retrospective cephalometric study was to test an additional function of the TPA: its ability to enhance orthodontic anchorage during extraction treatment.
Records consisting of pretreatment and posttreatment cephalograms were gathered from several orthodontic practices that used an .018 x .025-in preangulated appliance. All patients were white and had 4 first premolars extracted as part of their treatment protocol. Patients were treated either with or without a TPA of the soldered Goshgarian design. Patients were excluded if headgear or any other auxiliary anchorage device beside the TPA was used during treatment. Matched samples of 30 patients were identified based on sex, age at the start of treatment, treatment duration, and cervical vertebral maturation stage. Statistical comparisons were made with nonparametric statistical tests.
Analysis of the changes from pretreatment to posttreatment for the TPA and the no-TPA groups showed no statistically significant differences in any of the variables examined. The net difference for both vertical and mesial movement of the maxillary first molar in relation to the maxilla between the 2 groups was 0.4 mm, with the no-TPA group in a more downward and forward position.
Although the usefulness of the TPA for the abovementioned functions is not negated, it does not provide a significant effect on either the anteroposterior or the vertical position of the maxillary first molars during extraction treatment.
跨腭弓（TPA）可在正畸治疗期间用作辅助装置，以帮助在三维空间中控制上颌第一磨牙的移动，包括产生磨牙旋转和直立、在治疗期间保持后部的横向尺寸以及在牙列转换期间保持间隙。这项回顾性头影测量研究的目的是测试TPA的一项额外功能：其在拔牙治疗期间增强正畸支抗的能力。
从几家使用0.018×0.025英寸预成角矫治器的正畸诊所收集了治疗前和治疗后的头影测量记录。所有患者均为白人，作为治疗方案的一部分拔除了4颗第一前磨牙。患者接受了带或不带焊接式戈什加里安设计TPA的治疗。如果在治疗期间使用了头帽或TPA以外的任何其他辅助支抗装置，则将患者排除。根据性别、治疗开始时的年龄、治疗持续时间和颈椎成熟阶段，确定了30例患者的匹配样本。使用非参数统计检验进行统计比较。
对TPA组和无TPA组从治疗前到治疗后的变化分析显示，在所检查的任何变量中均无统计学显著差异。两组上颌第一磨牙相对于上颌骨的垂直和近中移动的净差异均为0.4mm，无TPA组处于更向下和向前的位置。
尽管TPA对上述功能的有用性并未被否定，但它在拔牙治疗期间对上颌第一磨牙的前后或垂直位置均未产生显著影响。
