Three-dimensional finite element analysis of the mandible reconstruction with fibula / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To construct a three-dimensional finite element model of reconstructed mandible and analyze the stress distributions of the model.</p><p><b>METHODS</b>CT scan and CAD/CAM software was used to develop the three-dimensional finite element model of reconstructed mandible and stress analysis was performend with ANASYS 7.0 software.</p><p><b>RESULTS</b>The three-dimensional finite element models of normal mandible and reconstructed mandible were constructed. The stress analysis discovered an unbalanced stress distribution in the mandible.</p><p><b>CONCLUSION</b>Reconstructing mandible with fibular flap not only damages its structure, but also induced the badness of its biomechanical environment, in which condyle was the most sensitive region during the stresses in the mandible were changed.</p>

Design and biomechanical evaluation of obturator prostheses with removable partial denture / 生物医学工程学杂志

The closed palate and obturator prostheses with bar clasp and attachment retention were designed and modeled for repairing the unilateral defect maxillary, and then they were analyzed using finite element method. Under simulated muscle restriction and masticating force boundary, the strength of four maxillary prostheses, the attachment, base plate, bar clasp, denture, obturator et cetera, were considered, and the stress dimension and tendency of the rest living teeth and prostheses were studied. According to the studies on stress, the optimized structure and biomechanical evaluation have a role in the repairs to maxillary defect. The results of analysis are as follows: The stresses of each part of the prostheses were all in the strength range of the materials. The stress distribution on the rest living teeth and alveolar bone was reasonable; the biting force was effectively transferred by the prostheses. As to the obturator prostheses, the materials properties were similar to those of alveolar bone or a bit lower than those, and the obturator structure filled in the cavum of maxillary bone to increase the touch area in the structure was more reasonable than the palate closed structure. The stress and displacement results of living teeth showed that the attachment retention and obturator prostheses could avoid the stress concentration on living teeth and could benefit the retention and power support.

Study of biomechanical effects on the reconstruction of mandible defect with autogenous bone grafts / 生物医学工程学杂志

The biomechanical effects of the reconstructed mandible with autogenous bone grafts were analyzed and evaluated, under simulated mechanical environment of occlusion. Based on anatomical feature of the human skeleton, muscle system and the clinical B, BS"S" and RB"S"defect patterns, the modularized model of mandible and the three finite element models of the fibula grafts and iliac crest grafts reconstruction mandible were made. The stress state calculations under bite force were also processed. The findings are as follows: Along the right connection area to left connection area (corresponding to far-end of the molar teeth alveolar ridge and the chin section respectively), the stress state on the various grafted bone all changes from compression stress to tensile stress. There is obvious change on the stress distribution between the fibula type reconstruction mandible and normal one. The stress on the grafted bone which is mainly made up of cortical bone is approximately 5 times higher than that of normal, which indicates the obvious stress shielding effect; the stress distribution of the iliac crest type reconstruction mandible is close to the normal mandible, the iliac crest used is mainly made up of cancellous. Therefore, the mechanical properties of the reconstructed mandible with iliac crest are more similar to normal mandible, which is beneficial to wound healing and further functional reconstruction.