Korean J Orthod.  2025 May;55(3):193-201. 10.4041/kjod24.286.

Effects of clear aligner edentulous space design on distal canine movement: An iterative finite element analysis in cases involving extraction

• Baek SE
• Kim K
• Choi YK
• Kim SH
• Kim SS
• Kim KB
• Kim YI

• KMID: 2568342
• DOI: http://doi.org/10.4041/kjod24.286

Abstract

Objective
Using finite element method (FEM) analysis of a clear aligner (CA), this study aimed to investigate the effects of varying the edentulous space on canine distal bodily movement during space closure following maxillary first premolar extraction.
Methods
FEM analysis was used to simulate distal canine bodily movement following maxillary first premolar extraction using CAs. Four CA designs for edentulous spaces were compared: no-pontic, full-pontic, halfpontic, and beam. Three-dimensional models of the tooth components and CA were created. The target was set at a 0.25-mm distal canine movement. Long-term tooth movement was simulated using an iterative calculation method.
Results
All the groups initially showed crown displacement, distal tipping, and distal rotation. Over time, the movement patterns differed in relation to the design. The no-pontic design exhibited the greatest displacement and tipping. The beam design exhibited the largest initial displacement but showed the lowest displacement and tipping thereafter. Full- and half-pontic designs yielded intermediate results. Significant force reduction was observed immediately after CA application, and was followed by a gradual decrease. The mean tooth-movement achievement rate was approximately 76.7%.
Conclusions
The edentulous space design of the CA substantially affected tooth-movement behavior. An iterative simulation is necessary to evaluate longterm tooth-movement patterns. The beam design demonstrated optimal suitability for bodily movement with minimal tipping. For optimal results, additional setup or overcorrection may be necessary.

Keyword

Finite element method; Extraction space; Clear aligner design

Figure

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  Figure 1 All components of the finite element method model with the coordinate system.

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  Figure 2 Four designs of the clear aligner finite element method model. A, Group 1: No-pontic design; B, Group 2: Full-pontic design; C, Group 3: Half-pontic design; D, Group 4: Beam design.

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  Figure 3 Comparative displacements of the maxillary right canine across the four groups.

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  Figure 4 Canine distal tipping obtained by iterative calculations in the four groups.

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  Figure 5 Occlusal view of canine distal rotation across the four groups during iterative calculations.

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  Figure 6 Canine movement patterns over 50 iterations (n = 50).

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  Figure 7 Stage-dependent changes in canine force with aligner designs. A, Overall force across 50 stages; B, Detailed view of force distribution.

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  Figure 8 Changes in canine moment across different aligner designs.

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