Three-dimensional finite element analysis of different pontic designs in the extraction area of clear aligners during the distalization of canine

doi:10.11958/20251185

Abstract

Abstract:

Objective To explore the effect of different pontic designs in resisting stress interruption effect and roller coaster phenomenon through three-dimensional finite element analysis, providing clinical guidance for the application of clear aligners in extraction cases. Methods Four three-dimensional finite element models of different pontic designs in the extraction area of clear aligners were established, including the pontic-free connection design, the conventional hollow pontic design, the partially solid-filled pontic design and the fully solid-filled pontic design. All four aligner models were individually assembled with the dental arch model. A 0.2 mm distal movement of the canine was simulated to observe the initial displacement and periodontal ligament stress distribution of canine and second premolar in each group of models. Results The initial displacement tendency diagram revealed that in all experimental conditions, both the canine and second premolar exhibited tipping movement patterns. However, significant variations in initial displacement magnitudes were observed across different pontic designs. The fully solid-filled pontic-connected clear aligner model exhibited the greatest initial displacement values (both crown and root) and the maximum initial displacement magnitude. Notably, this kind of design displayed movement characteristics closer to bodily movement, indicating superior control efficacy in tooth positioning. Periodontal ligament stress analysis revealed that the fully solid-filled pontic-connected clear aligner model generated the highest maximum principal stress in the periodontal ligament.Conclusion This three-dimensional finite element study reveals that the application of solid-filled pontic in clear aligner therapy could improve biomechanical control at extraction sites by minimizing aligner distortion, reducing stress interruption effect and preventing the roller coaster phenomenon.

Key words: tooth abnormalities, orthodontic appliances, finite element analysis, clear aligner technology

CLC Number:

R783.5

Figures/Tables 9

References 17

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组别	节点数	单元数
组合模型1	205 195	333 679
组合模型2	206 254	335 767
组合模型3	212 213	361 155
组合模型4	216 416	381 990

组别	节点数	单元数
组合模型1	205 195	333 679
组合模型2	206 254	335 767
组合模型3	212 213	361 155
组合模型4	216 416	381 990

材料	弹性模量/MPa	泊松比
牙列及附件	19 600	0.30
牙周膜	0.05	0.49
无托槽隐形矫治器	528	0.40

材料	弹性模量/MPa	泊松比
牙列及附件	19 600	0.30
牙周膜	0.05	0.49
无托槽隐形矫治器	528	0.40

牙位	工况	最大位移量/mm	根尖点位移/mm	颊侧牙尖点位移/mm	R/C 比值
尖牙	工况1	0.128	0.056	-0.121	-0.462
	工况2	0.119	0.052	-0.112	-0.467
	工况3	0.128	0.056	-0.120	-0.464
	工况4	0.134	0.058	-0.125	-0.461
第二前磨牙	工况1	0.053	-0.018	0.036	-0.490
	工况2	0.046	-0.016	0.031	-0.498
	工况3	0.055	-0.018	0.038	-0.479
	工况4	0.058	-0.019	0.042	-0.460