Predicting Residual Stress on X-ray Tomographed Complex Bi-Layer Geometries using 3D Finite Element Analysis

Micro-Computed Tomography was performed on an artificial mandibular first molar crown. A complex bi-layer geometry finite element model representing a real dental crown shape was created by converting 3D reconstructed micro-tomographs into a meshed model. The distribution of thermal residual stresses, provided by finite elements, demonstrated how thickness of the veneer contributes to localized compressive residual stress at the external surface of the veneer layer. To inhibit fracture initiation, it is desirable to manufacture a crown with compressive residual stress on its external surface. In order to quantify the correlation between thicknesses of the veneer layer and compressive residual stress at the external surface of the veneer, the local thickness of each surface node is required. The method introduced here computes the minimum distance between two triangulated complex surfaces by finding the closest point on the facing surface for each surface vertex. Statistical correspondence between local thickness of the veneer layer and the calculated residual stress components from finite elements revealed a curvilinear relationship over the range of variables and suggests a preferred layer thickness for engineering future dental restorations.