Influence of framework design on shear stress distribution

Objectives: The purpose of this study was to evaluate the influence of the framework design on shear stress distribution of adhesive resin cements by means of three-dimensional finite element analysis The purpose of this study was to evaluate the influence of the framework design on shear stress distribution of adhesive resin cements by means of three-dimensional finite element analysis.
Methods: Micro computer tomography(Micro-CT) imaging by Micro focus X-ray computer tomography System were used to obtain the Digital Imaging and Communication in Medicine (DICOM) data that is in a range of the upper left central incisor to the upper left canine of the human dry skull. The DICOM data was converted into the Standard Triangulated Language data, and then trim the upper left lateral incisor. After 3D construction, the model was produced by resin material.
The model of the upper left central incisor and the canine were prepared for the resin-bonded fixed partial dentures (RBFPDs). The palatal surface was reduced as a 0.5-mm-thick veneer. Two vertical grooves were prepared on the both side of proximal surfaces and the hole was prepared at the cingulum area.
After Micro-CT scan was performed the model, the scanned images were converted to the DICOM format.
FEA was performed to measure the shear stress distribution of adhesive resin cements when the two types of 3-unit RBFPDs (0.5mm Y-TZP, 0.8mm Silver-palladium alloy) were set on the abutment teeth. The loading direction was at 45 degrees to the long axis of the abutment teeth and the load was applied onto the center of the pontic.
Results: The volume-percentage of adhesive resin cement, which were applied the shear stress (>11 MPa : allowable shearing stress of the PanaviaF2.0 ) of the 0.5mm Y-TZP framework and 0.8mm Silver-palladium alloy framework were 3.36% and 3.34%.
Conclusions: The RBFPDs using 0.5-mm-thick Y-TZP framework is effective method for the anterior single missing tooth because of the less amount of tooth reduction compared with that of using Silver-palladium alloy framework.