J Dent Rehabil Appl Sci.  2023 Jun;39(2):61-68. 10.14368/jdras.2023.39.2.61.

Influence of tongue pressure on the obturator prosthesis for soft palate defects: a 3D-FEA study

• Mon A
• Kim ME
• Lim YJ
• Kim MJ
• Kwon HB

• KMID: 2549273
• DOI: http://doi.org/10.14368/jdras.2023.39.2.61

Abstract

Purpose
The purpose of the study was to analyze how swallowing tongue pressure affects the biomechanics of a velopharyngeal obturator prosthesis and compare its displacement across different occlusal rest positions.
Materials and Methods
A 3D geometric model consisting of the maxilla, teeth, soft palate, and a portion of the pharynx was developed based on the CBCT and MRI data. A defect was created by the resection of soft palate portion. Two experimental models were generated based on two different velopharyngeal obturator designs: one “with mesial occlusal rests” (Model 1) and the other with “distal occlusal rests” (Model 2). A pressure of 25 kPa was applied at the surface of the bulb of the obturator prosthesis opposite the base of the tongue to simulate tongue pressure during swallowing. The maximum von-Mises stress and displacement values of two types of obturator prostheses were analyzed and compared.
Results
The maximum von-Mises stress in the metal framework, located at the posterior palatal strap, was slightly higher in model 1 (64.9 MPa) than in model 2 (54.2 MPa). In both models, the acrylic resin obturator bulb exhibited a maximum stress value of 4.3 MPa. There was no significant difference in prosthesis displacement between the two models, with 31.3 µm for model 1 and 33.6 µm for model 2.
Conclusion
Swallowing tongue pressure had a minor impact on the biomechanics of a velopharyngeal obturator prosthesis, and distal occlusal rests showed a slightly better biomechanical response compared to mesial occlusal rests.

Keyword

finite element analysis; occlusal rest; swallowing; tongue pressure; velopharyngeal closure

Figure

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  Fig. 1 3D FEA soft palate defect model: (A) occlusal view, (B) lateral view.

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  Fig. 2 Velopharyngeal obturator models: (A) model 1 with mesial occlusal rests, (B) model 2 with distal occlusal rests.

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  Fig. 3 von-Mises stress distributions in the velopharyngeal obturator prostheses: (A) with mesial occlusal rests, (B) with distal occlusal rests.

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  Fig. 4 Displacement distribution pattern of the velopharyngeal obturator prostheses: (A) with mesial occlusal rests, (B) with distal occlusal rests.

Reference

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