Three-dimensional finite element analysis of different attachment designs for lateral incisors during inward retraction of upper anterior teeth in clear aligner

doi:10.19439/j.sjos.2024.04.005

Abstract

Abstract: PURPOSE: To investigate the biomechanical expression of different shapes of attachments on the maxillary anterior teeth during the lingual tooth movement process using clear aligners, providing new insights for orthodontists to improve the clinical design. METHODS: In this study, CBCT data were simulated using the three-dimensional finite element technique. Attachments of various shapes, including no attachment(A1), rectangular attachment(A2), wedge-shaped attachment(A3), and curved arc attachment(A4), were designed on the lateral incisors. Ansys software was employed to calculate the three-dimensional changes in the lateral incisors, dental arch, and clear aligners and the distribution of equivalent stress on the periodontal ligament(von Mises) under the same load conditions. RESULTS: The coronal displacement of the lateral incisors showed the following variations: A1>A4>A3>A2. The sagittal displacement exhibited the following variations: A3>A4>A1>A2. The vertical elongation demonstrated the following variations: A4>A3> A1>A2. The overall displacement of each dental arch displayed an arch-shaped trend. Different regions of the clear aligners exhibited variations in deformation. The von Mises distribution of the periodontal ligament in A1 and A2 group showed similarities, while A3 group exhibited stress concentration only in the lingual area of the root's one-third region. Group A4 experienced significantly higher stress in the cervical region compared to A1 and A2 group. CONCLUSIONS: Rectangular attachments and curved arc attachments possess advantages in coronal control, with rectangular attachments exhibiting the best control effect in vertical control. The area of attachment force and actual displacement efficiency do not have an absolute correlation, as the shape of the force-bearing surface can significantly affect its specific biomechanical expression.

Key words: Three-dimensional finite element analysis, Clear aligner deformation trend, Lateral incisor attachment, Clear aligner

CLC Number:

R783.5

CHEN Jing-cheng, ZHAO Meng-li, CHENG Zhi-heng, LIU Xin. Three-dimensional finite element analysis of different attachment designs for lateral incisors during inward retraction of upper anterior teeth in clear aligner[J]. Shanghai Journal of Stomatology, 2024, 33(4): 360-366.

References

[1] Linjawi AI, Abushal AM.Adaptational changes in clear aligner fit with time[J]. Angle Orthod, 2022, 92(2): 220-225.
[2] Ben Gassem AA.Does clear aligner treatment result in different patient perceptions of treatment process and outcomes compared to conventional/traditional fixed appliance treatment:a literature review[J]. Eur J Dent, 2022, 16(2): 274-285.
[3] Zhang Y, Wang X, Wang J, et al.IPR treatment and attachments design in clear aligner therapy and risk of open gingival embrasures in adults[J]. Prog Orthod, 2023, 24(1): 1-8.
[4] Xia Q, He Y, Jia L, et al.Assessment of labially impacted canines traction mode with clear aligners vs. fixed appliance: a comparative study based on 3D finite element analysis[J].Front Bioeng Biotechnol, 2022, 10: 1004223.
[5] Hong K, Kim WH, Eghan-Acquah E, et al.Efficient design of a clear aligner attachment to induce bodily tooth movement in orthodontic treatment using finite element analysis[J]. Materials (Basel), 2021, 14(17): 4926.
[6] Liu L, Song Q, Zhou J, et al.The effects of aligner overtreatment on torque control and intrusion of incisors for anterior retraction with clear aligners: a finite-element study[J]. Am J Orthod Dentofacial Orthop,2022,162(1): 33-41.
[7] Cheng Y, Liu X, Chen X, et al.The three-dimensional displacement tendency of teeth depending on incisor torque compensation with clear aligners of different thicknesses in cases of extraction:a finite element study[J]. BMC Oral Health, 2022, 22(1): 499-511.
[8] Seo JH, Eghan-Acquah E, Kim MS, et al.Comparative analysis of stress in the periodontal ligament and center of rotation in the tooth after orthodontic treatment depending on clear aligner thickness—finite element analysis study[J]. Materials (Basel), 2021, 14(2): 324-340.
[9] Liu L, Zhan Q, Zhou J, et al.Effectiveness of an anterior mini-screw in achieving incisor intrusion and palatal root torque for anterior retraction with clear aligners[J]. Angle Orthod, 2021, 91(6): 794-803.
[10] Jiang T, Wu RY, Wang JK, et al.Clear aligners for maxillary anterior en masse retraction:a 3D finite element study[J]. Sci Rep, 2020, 10(1): 10156.
[11] Li Y, Xiao S, Jin Y, et al.Stress and movement trend of lower incisors with different IMPA intruded by clear aligner:a three-dimensional finite element analysis[J]. Prog Orthod, 2023, 24(1): 5-17.
[12] Sachdev S, Tantidhnazet S, Saengfai NN.Accuracy of tooth movement with in-house clear aligners[J]. J World Fed Orthod, 2021, 10(4): 177-182.
[13] Nucera R, Dolci C, Bellocchio AM, et al.Effects of composite attachments on orthodontic clear aligners therapy: a systematic review[J]. Materials(Basel), 2022, 15(2): 533-550.
[14] Haouili N, Kravitz ND, Vaid NR, et al.Has invisalign improved? a prospective follow-up study on the efficacy of tooth movement with Invisalign[J]. Am J Orthod Dentofacial Orthop, 2020, 158(3): 420-425.
[15] Ayidaga C, Kamiloglu B.Effects of variable composite attachment shapes in controlling upper molar distalization with aligners: a nonlinear finite element study[J]. J Healthc Eng, 2021: 5557483.
[16] Laohachaiaroon P, Samruajbenjakun B, Chaichanasiri E.Initial displacement and stress distribution of upper central incisor extrusion with clear aligners and various shapes of composite attachments using the finite element method[J]. Dent J (Basel), 2022, 10(6): 114-123.