[Maxillary expansion efficiency with clear aligner and its possible influencing factors].

抄録

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.

评价无托槽隐形矫治的上颌扩弓效率，并探讨相关影响因素。 选取上海交通大学医学院附属第九人民医院口腔正畸科于2014年1月至2016年12月期间使用无托槽隐形矫治器（Invisalign）完成上颌扩弓的病例31例，收集矫治前、软件预置结果以及矫治后实际结果的三维数字化牙列模型，测量上颌牙弓宽度和后牙颊倾度，计算扩弓效率（实际扩弓量÷预置扩弓量×100%）。对矫治前后数据进行检验，分析扩弓量、颊倾度、附件、扩弓方式等因素对扩弓效率的影响。 与矫治前相比，矫治后各牙位牙弓宽度均显著增加（0.05）；尖牙、第一和第二前磨牙、第一和第二磨牙区的实际扩弓量分别为（2.0±1.3）、（2.8±1.5）、（3.0±1.4）、（1.8±1.0）和0.5（0.1，1.1）mm，扩弓效率分别为68%、70%、68%、55%和29%。后牙矫治后实际颊倾度均显著大于预置值（0.05），但颊倾度差值最大的第一磨牙仅为3.1°±3.9°。对于磨牙预置扩弓量<2 mm的患者（15例），其前磨牙的扩弓效率显著大于磨牙预置扩弓量≥2 mm的患者（16例）（0.05）。预置颊倾度、附件和扩弓方式对扩弓效率无显著影响。 无托槽隐形矫治能有效扩大上颌牙弓，对后牙颊向倾斜的控制较好，扩弓效率从近中到远中逐渐降低；减小磨牙预置扩弓量能提高前磨牙区的扩弓效率。.