The effect of enhanced structure in the posterior segment of clear aligners during anterior retraction: a three-dimensional finite element and experimental model analysis

作者全名："Jin, Xiaohan; Tian, Xue; Lee Zhi Hui, Victoria; Zheng, Yikan; Song, Jinlin; Han, Xianglong"

作者地址："[Jin, Xiaohan; Lee Zhi Hui, Victoria; Han, Xianglong] Sichuan Univ, State Key Lab Oral Dis, Natl Clin Res Ctr Oral Dis, West China Hosp Stomatol,Dept Orthodont, 14,3Rd Sect Ren Min Nan Rd, Chengdu 610041, Sichuan, Peoples R China; [Tian, Xue] Jiangmen Municipal Stomatol Hosp, Yongli St,Shengli Rd, Jiangmen 529000, Guangdong, Peoples R China; [Zheng, Yikan] EA Med Device Technol Co Ltd, R&D Ctr, Middle Branch Rd, Wuxi 214174, Jiangsu, Peoples R China; [Song, Jinlin] Chongqing Med Univ, Stomatol Hosp, Chongqing Key Lab Oral Dis & Biomed Sci, Chongqing Municipal Key Lab Oral Biomed Engn Highe, 426 Songshibei Rd, Chongqing, Peoples R China"

通信作者："Han, XL (通讯作者)，Sichuan Univ, State Key Lab Oral Dis, Natl Clin Res Ctr Oral Dis, West China Hosp Stomatol,Dept Orthodont, 14,3Rd Sect Ren Min Nan Rd, Chengdu 610041, Sichuan, Peoples R China."

来源：PROGRESS IN ORTHODONTICS

ESI学科分类：CLINICAL MEDICINE

WOS号：WOS:001142020000001

JCR分区：Q1

影响因子：4.8

年份：2024

卷号：25

期号：1

开始页：　

结束页：　

文献类型：Article

关键词：Clear aligner; Extraction case; Anterior retraction; Finite element analysis; Anchorage reinforcement

摘要："BackgroundMesial tipping of posterior teeth occurs frequently during space closure with clear aligners (CAs). In this study, we proposed a new modification of CA by localized thickening of the aligner to form the enhanced structure and investigate its biomechanical effect during anterior retraction.MethodsTwo methods were employed in this study. First, a finite element (FE) model was constructed, which included alveolar bone, the first premolars extracted maxillary dentition, periodontal ligaments (PDL), attachments and aligners. The second method involved an experimental model-a measuring device using multi-axis transducers and vacuum thermoforming aligners. Two groups were formed: (1) The control group used common CAs and (2) the enhanced structure group used partially thickened CAs.ResultsFE model revealed that the enhanced structure improved the biomechanics during anterior retraction. Specifically, the second premolar, which had a smaller PDL area, experienced a smaller protraction force and moment, making it less likely to tip mesially. In the same vein, the molars could resist movement due to their larger PDL area even though they were applied larger forces. The resultant force of the posterior tooth was closer to the center of resistance, reducing the tipping moment. The canine was applied a larger retraction force and moment, resulting in sufficient retraction of anterior teeth. The experimental model demonstrated a similar trend in force variation as the FE model.ConclusionsEnhanced structure allowed force distribution more in accordance with optimal principles of biomechanics during the extraction space closure while permitting less mesial tipping and anchorage loss of posterior teeth and better retraction of anterior teeth. Thus, enhanced structure alleviated the roller coaster effect associated with extraction cases and offered a new possibility for anchorage reinforcement in clear aligner therapy."

基金机构："EA Medical Center Device Technologies Co., Ltd."

基金资助正文：We thank Lei Huang and Xianbo Xu for their assistance with this study.