ORIGINAL RESEARCH article
Front. Bioeng. Biotechnol.
Sec. Biomaterials
Volume 13 - 2025 | doi: 10.3389/fbioe.2025.1636262
This article is part of the Research TopicAdvanced Technologies for Oral and Craniomaxillofacial TherapyView all 16 articles
Finite Element Analysis of Clear Aligner with Overhanging Attachments and Extended Gingival Coverage for Interdental Space Closure
Provisionally accepted
- 1Shanghai University of Medicine and Health Sciences, Shanghai, China
- 2Xuzhou Medical University, Xuzhou, China
- 3Shanghai Xuhui District Dental Center, Shanghai, China
- 4Shanghai University of Medicine and Health Sciences Affiliated Zhoupu Hospital, Shanghai, China
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Objective: Overhanging (OH) attachments were modified clear aligner (CA) attachments with an extended portion toward the root to apply force closer to the center of resistance and enable greater control over root movement, resembling power arms. This study investigated the biomechanical effects of OH attachment and partially gingival extension of CA trimline on canine movement during the closure of extraction space via finite element analysis (FEA). Methods: CBCT data of an adult with Angle Class I molar relationship and mild anterior crowding was applied for comparing the biomechanical effects of three attachment types (no attachment, vertical, OH) and four trimline designs (partially buccal/lingual gingival coverage). Periodontal ligament (PDL) hydrostatic stress, tooth displacement, rotational center position, and CA stress distribution were assessed via FEA. Results: OH attachment induced increased tooth displacement and PDL hydrostatic stress (95.5 kPa) compared to regular vertical attachment (53.1 kPa) in achieving root-controlled canine movement. OH attachment combined with a buccolingual gingival extension of CA trimline on 2~6 facilitated the most translational canine movement and lowest ratio of mesio-apical to disto-occlusal displacement (0.466, compared to 0.506 in group with no attachment and trimline extension), while simultaneously avoiding excessive aligner deformation and stress concentration. Conclusion: Overhanging attachment combined with partial gingival extension of CA trimline significantly enhanced the orthodontic force for premolar extraction cases involving space closure between canines and molars, as a more efficient and feasible design for canine bodily movement.
Keywords: Clear aligners, Finite Element Analysis, Overhanging Attachment, bodily movement, Interdental Space Closure
Received: 27 May 2025; Accepted: 21 Oct 2025.
Copyright: © 2025 Zeng, Ma and Lin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Xiaoqing Ma, mxq780927@163.com
Dan Lin, lind@sumhs.edu.cn
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