A New Method for Evaluating Thermal Compatibility of Multi-Layer Dental Ceramic Composites

Abstract

Dental ceramic materials do not always show linear expansion behavior. In general, thermal contraction behavior of dental porcelain can be described with the polynomial function: L/L= C+α1 T+α2 T2. In addition, a new method for taking into consideration of nonlinear contraction behavior of dental ceramics is proposed for calculating thermal mismatch value (α) between substrate and veneering materials. Discs of eight substrate/veneer combinations (n=10) were fabricated for thermal shock testing. In this study, a stepwise multiple regression analysis was performed to determine the relationship between thermal shock test results and thermal mismatch value (α) on these combinations. A high degree of correlation was found between αs-b and T. The new method proves to be a reliable one to predict thermal compatibility of multi-layer dental ceramic composites.