Analysis of thermally-induced stresses in porcelain-metal systems.

An analysis of the stresses which develop during air cooling and shock testing of a simulated porcelain-metal crown is presented. Strain gauges were used to experimentally determine porcelain surface stresses during shock testing. The finite element method was used to calculate stress patterns throughout the simulated crown. This study indicates that the previously reported high degree of correlation between dilatometry-derived compatibility index values and delta T values may be related to porcelain tensile strengths and defect density.