Residual stresses in fabrication of core-veneered ceramic prostheses

Fabrication of multilayered ceramics signifies an important topic in many advanced applications aerospace and prosthetic dentistry. This paper presents a numerical approach to characterising the transient thermal responses and corresponding thermal residual stresses that are developed in the bi-layered dental ceramic crowns model under a controlled cooling rate from a temperature around its glass transition temperature (typically 550°C) to room temperature (25°C). Finite element method (FEM) is adopted to model the residual stresses in normal or rapid cooling fabrication process. The demonstrative examples take into account the effect of thickness in core veneered all-ceramic restorative prosthesis (specific porcelain bonded to an alumina or zirconia core layer), cooling rates and mismatches in temperature-dependent material properties such as thermal expansion coefficients, specific heat and Young's modulus. The model of transient ceramic fabrication processing showed significant potential to development of optimal prosthetic devices.