Methods: A two dimensional conduction model was developed and solved analytically. A computer program in MATLAB was developed, based on the analytical solutions to predict the cooling profiles for each disk.
Results: For a body porcelain disk, 2 mm in thickness and 16 mm in diameter subjected to free convective cooling from an initial temperature of 800°C, the maximum value of principal tensile stress was 39 MPa. However, for a bi-layered ceramic disk with a thermal mismatch level of 1.5 ppm/°C, the corresponding stress value increased to 55 MPa.
Conclusions: Comparison of the results from the analytical model, with those from the models based on finite element analysis, showed a good agreement, which supported the validity of analytical solutions and computational models used in this study. Thermal contract mismatch of porcelain layers had a significant impact on the magnitude of transient thermal stresses developed with the samples during cooling. The finite element analysis and 3-D printing/prototyping techniques are being applied to develop simulated and physical models of the restorations to analyze the strength behaviors of the porcelain samples and compare them with the experimental data. This study was supported by a Quality Enhancement Program (QEP) Grant from Valdosta State University.
This abstract is based on research that was funded entirely or partially by an outside source: This study was supported by a Quality Enhancement Program (QEP) Grant from Valdosta State University.