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Abstract
Purpose
The purposes of this study were to evaluate the stress distributions and the displacements of obturator for edentulous maxillectomy patients and to compare them with those of complete denture using three-dimensional finite element analysis.
Materials and methods
Based on the CT image of edentulous patient, three-dimensional finite element model of edentulous maxillae was constructed. Three-dimensional finite element model of edentulous maxillae with palatal defect was also fabricated. On each model, complete denture and obturator prosthesis were created. Vertical static force of 200 N was applied on the left maxillary premolar and molar region. The von Mises stress values and the displacements of models were analyzed using three-dimensional finite element analysis.
Results
Maximum von Mises stress values were recorded in the cortical bones of both models. The von Mises stress value in the complete denture model was 2.73 MPa and 2.69 MPa in the obturator model. High von Mises stress values were also observed on the tissue surface of prosthesis. The maximum value of the displacement in the obturator was higher than that of complete denture.
Conclusion
The obturator showed a worse result in terms of stress distribution and displacement than complete denture. In the prosthodontic rehabilitation of edentulous maxillectomy patient accurate impression procedure based on patients’ anatomy and application of prosthodontic principle should be considered. (J Korean Acad Prosthodont 2011;49:222-8)
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Fig. 1.
Geometries of the finite element models in this study. A: edentulous maxilla, B: maxillary complete denture, C: edentulous maxilla with palatal defect, and D: maxillary obturator.
Fig. 2.
Contour plots of von Mises stress distribution in obturator model model (GPa). A: tissue surface of obturator, B: cortical bone, and C: cancellous bone.
Fig. 3.
Contour plots of displacement in the obturator prosthesis (mm). A: tissue surface of obturator, and B: cortical bone.
Fig. 4.
Contour plots of von Mises stress distribution in the complete denture model(GPa). A: tissue surface of complete denture, B: cortical bone, and C: cancellous bone.
Fig. 5.
Contour plots of displacement in complete denture (mm). A: tissue surface of obturator, and B: cortical bone.
Table 1.
Elements and nodes
Table 2.
Material's properties
| Material | Young's modulus (Gpa) | Poisson's ratio |
|---|---|---|
| Denture resin (PMMA) | 2.0 | 0.35 |
| Cortical bone | 14.0 | 0.30 |
| Cancellous bone | 1.5 | 0.45 |
| Mucosa | 0.003 | 0.45 |
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