Three-dimensional Finite Element Analysis On Mandibular First Molar

Objective:To make a mechanical analysis on 3-dimensional finite element models of the mandibular first molar with half of the structure defect,which were restored by different filling materials and all-ceramic crown, and to provide a guideline for planning restoration for such kind of tooth structure defect.Methods:3D finite element models of the restored first mandibular molars were constructed by CT image reconstruction technique. Then MIMICS software was used to separate the areas and finish 3D calculation. GEOMAGIC software was also applied to modify and generate a NURBS surface in each patch. All components of the models were assembled under the ANSYS preprocessor. The von mises strength theory was applied for comparing the maximum von mises stress value of dentin and stress concentration areas in six models under the maximum,vertical,inclined and horizontal direct loads.Results:The restoration effects in six models were compared, the maximum von mises stress value of dentin and stress concentration areas were not obviously difference.The stress area in the model with amalgam filling and all-ceramic crown restoration was generally closer to the root tip than that in the model with composite resin filling and all-ceramic crown restoration.Conclusion:The location of residual dentin has little influence on the stress value and distribution, when restored by all-ceramic crown. The composite resin filling and the all-ceramic crown restoration are relatively better than amalgam filling and all-ceramic crown restoration.