1
|
Lyu X, Cao X, Chen L, Liu Y, Li H, Hu C, Tan J. Accumulated biomechanical effects of mandibular molar mesialization using clear aligners with auxiliary devices: an iterative finite element analysis. Prog Orthod 2023; 24:13. [PMID: 37032410 PMCID: PMC10083150 DOI: 10.1186/s40510-023-00462-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 03/07/2023] [Indexed: 04/11/2023] Open
Abstract
BACKGROUND The biomechanics generated by the clear aligner (CA) material changes continuously during orthodontic tooth movement, but this factor remains unknown during the computer-aid design process and the predictability of molars movement is not as expected. Therefore, the purpose of this study was to propose an iterative finite element method to simulate the long-term biomechanical effects of mandibular molar mesialization (MM) in CA therapy under dual-mechanical systems. METHODS Three groups including CA alone, CA with a button, and CA with a modified lever arm (MLA) were created. Material properties of CA were obtained by in vitro mechanical experiments. MM was conducted by the rebound force exerted by CA material and the mesial elastic force (2N, 30° to the occlusal plane) applied to the auxiliary devices. Stress intensity and distribution on periodontal ligament (PDL), attachment, button and MLA, and displacement of the second molar (M2) during the iterations were recorded. RESULTS There was a significant difference between the initial and cumulative long-term displacement. Specifically, compared to the beginning, the maximum stress of PDL decreased by 90% on average in the intermediate and final steps. The aligner was the main mechanical system at first, and then, the additional system exerted by the button and MLA dominated gradually. The stress of attachments and auxiliary devices is mainly concentrated on their interfaces with the tooth. Additionally, MLA provided a distal tipping and extrusive moment, which was the only group that manifested a total mesial displacement of the root. CONCLUSIONS The innovatively designed MLA was more effective in reducing undesigned mesial tipping and rotation of M2 than the traditional button and CA alone, which provided a therapeutic method for MM. The proposed iterative method simulated tooth movement by considering the mechanical characteristic of CA and its long-term mechanical force changes, which will facilitate better movement prediction and minimize the failure rate.
Collapse
Affiliation(s)
- Xinwei Lyu
- Department of Orthodontics, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, 510055, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, 510080, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Xing Cao
- Department of Orthodontics, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, 510055, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, 510080, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Luxian Chen
- Department of Orthodontics, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, 510055, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, 510080, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Yuyao Liu
- Department of Orthodontics, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, 510055, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, 510080, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Huilin Li
- Department of Orthodontics, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, 510055, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, 510080, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Cheng Hu
- Department of Orthodontics, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, 510055, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, 510080, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, 510080, China
| | - Jiali Tan
- Department of Orthodontics, Hospital of Stomatology, Sun Yat-Sen University, Guangzhou, 510055, China.
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, 510080, China.
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, 510080, China.
| |
Collapse
|
2
|
Palone M, Pavan F, Carlucci A, Lombardo L. Massive intrusion of maxillary second molar for prosthodontic purposes through miniscrew-supported biomechanics and fixed partial appliances: A case report. Int Orthod 2022; 20:100662. [DOI: 10.1016/j.ortho.2022.100662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/16/2022] [Accepted: 06/20/2022] [Indexed: 11/29/2022]
|