Different biomechanical effects of clear aligners in closing maxillary and mandibular extraction spaces: Finite element analysis

Liu, Junqi; Zhu, Guan-yin; Wang, Yi-gan; Zhang, Bo; Yao, Ke

doi:10.1016/j.ajodo.2022.07.021

Cited by 9 publications

(4 citation statements)

References 25 publications

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“…However, the observed trend was not as pronounced, potentially due to variations in force magnitude and application method. Liu’s study revealed that longer anterior teeth experienced less tipping [ 53 ], which aligns with the results obtained from our control group Model C0. Furthermore, our experimental group Model C3 deviated from this trend by showcasing a smaller displacement tendency for central incisors with shorter roots compared to canines.…”

Section: Discussionsupporting

confidence: 89%

“…The clear aligner models consistently demonstrated lingual tipping and extrusion in the anterior teeth, as well as a similar movement pattern in the posterior teeth with their crowns tilting towards the mesial side, consistent with the findings reported by Wang et al [ 50 , 51 ]. Retraction of the anterior teeth using clear aligners leads to a roller-coaster effect of tooth movement [ 5 , 50 , 52 , 53 ]. The additional force systems in the study did not change the observed trend of tooth movement in the model, but they did introduce some variation in the displacement magnitude of both anterior and posterior teeth.…”

Section: Discussionmentioning

confidence: 99%

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Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study

Xia,

Wang,

Wang

et al. 2024

BMC Oral Health

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Background The aim of this study is to conduct a comparative evaluation of different designs of clear aligners and examine the disparities between clear aligners and fixed appliances. Methods 3D digital models were created, consisting of a maxillary dentition without first premolars, maxilla, periodontal ligaments, attachments, micro-implant, 3D printed lingual retractor, brackets, archwire and clear aligner. The study involved the creation of five design models for clear aligner maxillary anterior internal retraction and one design model for fixed appliance maxillary anterior internal retraction, which were subsequently subjected to finite element analysis. These design models included: (1) Model C0 Control, (2) Model C1 Posterior Micro-implant, (3) Model C2 Anterior Micro-implant, (4) Model C3 Palatal Plate, (5) Model C4 Lingual Retractor, and (6) Model F0 Fixed Appliance. Results In the clear aligner models, a consistent pattern of tooth movement was observed. Notably, among all tested models, the modified clear aligner Model C3 exhibited the smallest differences in sagittal displacement of the crown-root of the central incisor, vertical displacement of the central incisor, sagittal displacement of the second premolar and second molar, as well as vertical displacement of posterior teeth. However, distinct variations in tooth movement trends were observed between the clear aligner models and the fixed appliance model. Furthermore, compared to the fixed appliance model, significant increases in tooth displacement were achieved with the use of clear aligner models. Conclusions In the clear aligner models, the movement trend of the teeth remained consistent, but there were variations in the amount of tooth displacement. Overall, the Model C3 exhibited better torque control and provided greater protection for posterior anchorage teeth compared to the other four clear aligner models. On the other hand, the fixed appliance model provides superior anterior torque control and better protection of the posterior anchorage teeth compared to clear aligner models. The clear aligner approach and the fixed appliance approach still exhibit a disparity; nevertheless, this study offers a developmental direction and establishes a theoretical foundation for future non-invasive, aesthetically pleasing, comfortable, and efficient modalities of clear aligner treatment.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study

Xia,

Wang,

Wang

et al. 2024

BMC Oral Health

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“…In clinical practice, the four premolars extraction cases were more common, but we failed to construct the mandible. Liu et al reported that less anchorage loss occurred in mandibular teeth [ 38 ]. We assumed that less overtreatment is needed for the mandibular anchorage.…”

Section: Discussionmentioning

confidence: 99%

Effects of overtreatment with different attachment positions on maxillary anchorage enhancement with clear aligners: a finite element analysis study

Wang,

Huang,

Fan

et al. 2023

BMC Oral Health

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Background The effect of attachment positions on anchorage has not been fully explored. The aim of the present study is to analyze the effect of overtreatment with different anchorage positions on maxillary anchorage enhancement with clear aligners in extraction cases. Methods Models of the maxilla and maxillary dentition were constructed and imported into SOLIDWORKS software to create periodontal ligament (PDL), clear aligners, and attachments. Attachment positions on second premolars included: without attachment (WOA), buccal attachment (BA), and bucco-palatal attachment (BPA). Overtreatment degrees were divided into five groups (0°, 1°, 2°, 3°, 4°) and added on the second premolars. The calculation and analysis of the displacement trends and stress were performed using ANSYS software. Results Distal tipping and extrusion of the canines, and mesial tipping and intrusion of the posterior teeth occurred during retraction. A strong anchorage was achieved in cases of overtreatment of 2.8° with BA and 2.4° with BPA. Moreover, the BPA showed the best in achieving bodily control of the second premolars. When the overtreatment was performed, the canines and first molars also showed reduced tipping trends with second premolars attachments. And the stress on the PDL and the alveolar bone was significantly relieved and more evenly distributed in the BPA group. Conclusions Overtreatment is an effective means for anchorage enhancement. However, the biomechanical effect of overtreatment differs across attachment positions. The BPA design performs at its best for stronger overtreatment effects with fewer adverse effects.

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“…Previous studies have shown variations in the loading methods for CAs, including stress redistribution ( Jiang et al, 2020 ), interference fit ( Fan et al, 2022 ), thermal contraction ( Liu et al, 2023a ), displacement load ( Cardona et al, 2015 ) and birth-death elements ( Hong et al, 2021 ), all of which are recognized for their effectiveness. Based on a previous study ( Jiang et al, 2020 ), the loading method was further optimized by proposing a new approach based on the initial state field.…”

Section: Discussionmentioning

confidence: 99%

Effects of different intrusion patterns during anterior teeth retraction using clear aligners in extraction cases: an iterative finite element analysis

Zhang,

Wang,

et al. 2024

Front. Bioeng. Biotechnol.

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BackgroundOvertreatment design of clear aligner treatment (CAT) in extraction cases is currently primarily based on the clinical experience of orthodontists and is not supported by robust evidence on the underlying biomechanics. This study aimed to investigate the biomechanical effects of overtreatment strategies involving different maxillary anterior teeth intrusion patterns during anterior teeth retraction by CAT in extraction cases.Materials and methodsA finite element model of the maxillary dentition with the first premolar extracted was constructed. A loading method of clear aligners (CAs) based on the initial state field was proposed. The iterative method was used to simulate the long-term orthodontic tooth movement under the mechanical load exerted by the CAs. Three groups of CAs were utilized for anterior teeth retraction (G0: control group; G1: incisors intrusion group; G2: anterior teeth intrusion group). Tooth displacement and occlusal plane rotation tendency were analyzed.ResultsIn G0, CAT caused lingual tipping and extrusion of the incisors, distal tipping and extrusion of the canines, mesial tipping, and intrusion of the posterior teeth. In G1, the incisors showed minimal extrusion, whereas the canines showed increased extrusion and distal tipping tendency. G2 showed the smallest degree of posterior occlusal plane angle rotation, while the inclination tendency of the canines and second premolars decreased.Conclusion1. In CAT, tooth displacement tendency may change with increased wear time. 2. During anterior teeth retraction, the incisor intrusion pattern can provide effective vertical control for the lateral incisors but has little effect on the central incisors. Anterior teeth intrusion patterns can alleviate the inclination of canines and second premolars, resulting in partial relief of the roller-coaster effect.

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Different biomechanical effects of clear aligners in closing maxillary and mandibular extraction spaces: Finite element analysis

Cited by 9 publications

References 25 publications

Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study

Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study

Effects of overtreatment with different attachment positions on maxillary anchorage enhancement with clear aligners: a finite element analysis study

Effects of different intrusion patterns during anterior teeth retraction using clear aligners in extraction cases: an iterative finite element analysis

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