[Effect of pigments concentration on physical and mechanical properties of MDX-4-4210 silicone elastomer].

PURPOSE: To determine the optimum pigments concentration on the physical and mechanical properties. METHODS: In this study, control samples were prepared from MDX-4-4210 silicone base and tested along with the pigmented samples for comparison in accordance with the national standards. The pigments concentration to base elastomer was set at 0.1, 0.15, 0.2, 0.25, 0.3wt%,respectively; while other conditions were kept same, then the major physical properties of the elastomer were studied with a tensile tester. The data was processed with SPSS10.0 software package. RESULTS: When comparing the pigmented samples with the control, the tensile strength, the ultimate elongation, the tear resistance and the Shore A hardness of the MDX-4-4210 silicone elastomer was affected by the addition of the pigments. A decrease was found,while, the incorporation of pigments had no effect on the permanent deformation rate of the resulting elastomer by the addition of the pigments. CONCLUSIONS: The results obtained from physical and mechanical testing of pigmented silicone samples suggest that incorporation of 0.2wt% by weight of pigments can alter the initial physical and mechanical behavior of the base elastomer. Supported by National Natural Science Foundation of China (30630066).

[Construction of three-dimensional finite element model of human edentulous maxilla and cranial skeleton].

OBJECTIVE: To develop an effective and feasible method to construct three-dimensional finite element model of the whole edentulous maxilla and cranial skeleton. METHODS: Based on three-dimensional computer aided design model which was constructed by multi-slices helical CT scanning data of a male's head in specialized software, three-dimensional finite element model of edentulous maxillary and cranial skeleton was established; the stresses distribution in maxilla was investigated under occlusal load with computer simulated a complete overdenture. RESULTS: The three-dimensional finite element model of edentulous maxilla and cranial skeleton had favorite similarity in geometry, the distributions of stresses in maxilla and the wall of maxillary sinus could be clearly observed. CONCLUSIONS: The study verifies that this three-dimensional finite element modeling method is feasible and effective.