Zhao X, Wang H H, Yang Y M, Tang G H
Department of Orthodontics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine & Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology & National Clinical Research Center of Stomatology, Shanghai 200011, China.
Zhonghua Kou Qiang Yi Xue Za Zhi. 2017 Sep 9;52(9):543-548. doi: 10.3760/cma.j.issn.1002-0098.2017.09.006.
To evaluate the efficiency of maxillary expansion with clear aligners and to analyze the possible influence factors. Thiry-one clear aligner cases (Invisalign) with maxillary expansion were enrolled in this study. The three-dimensional (3D) digital models of pre-treatment, planned in Clincheck software and post-treatment were collected. Upper dental arch width, buccal inclination of posterior teeth, and the expansion efficiency (expansion acquired/expansion planned) were measured and calculated. The impact of factors such as planned buccal inclination, planned expansion amount, attachment, and the mode of expansion on the expansion efficiency were analyzed. The increases of upper arch width in canine, 1st and 2nd premolar, 1st and 2nd molar were (2.0±1.3), (2.8±1.5), (3.0±1.4), (1.8±1.0) and 0.5 (0.1, 1.1) mm, with their efficiency of 68%, 70%, 68%, 55% and 29%, respectively. The posterior teeth showed significantly more buccal inclination than the planned position (0.05). However, the most buccally inclined tooth detected in 1st molars was only 3.1°±3.9°. When the planned inter-molar width increase was less than 2 mm (15), the expansion efficiency of premolars was higher compared with those cases with the planned inter-molar width increase more than 2 mm (16, 0.05). The planned buccal inclination, attachments, and the expansion mode had no significant effect on the expansion efficiency (0.05). The expansion of maxillary arch with clear aligners was achieved by the buccal movement of the posterior teeth with limited buccal inclination. The efficiency of expansion declines from 1st premolars to second molars. The planned inter-molar width had a significant influence on the efficiency of premolar expansion.
评估使用透明矫治器进行上颌扩弓的效率，并分析可能的影响因素。本研究纳入了31例使用透明矫治器（隐适美）进行上颌扩弓的病例。收集了治疗前、Clincheck软件中计划的以及治疗后的三维（3D）数字模型。测量并计算上颌牙弓宽度、后牙颊倾度以及扩弓效率（获得的扩弓量/计划的扩弓量）。分析了计划颊倾度、计划扩弓量、附件以及扩弓方式等因素对扩弓效率的影响。上颌尖牙、第一和第二前磨牙、第一和第二磨牙处牙弓宽度增加量分别为（2.0±1.3）、（2.8±1.5）、（3.0±1.4）、（1.8±1.0）和0.5（0.1，1.1）mm，其效率分别为68%、70%、68%、55%和29%。后牙颊倾度明显大于计划位置（P<0.05）。然而，第一磨牙中检测到的最颊倾牙齿仅为3.1°±3.9°。当计划的磨牙间宽度增加小于2mm时（15例），前磨牙的扩弓效率高于计划磨牙间宽度增加大于2mm的病例（16例，P<0.05）。计划颊倾度、附件和扩弓方式对扩弓效率无显著影响（P>0.05）。使用透明矫治器进行上颌牙弓扩弓是通过后牙颊向移动实现的，颊倾度有限。扩弓效率从第一前磨牙到第二磨牙逐渐降低。计划的磨牙间宽度对前磨牙扩弓效率有显著影响。
