Evaluation of the Effect of Number of Firings on The Color Stability of Dental Ceramics - An in Vitro Study

Abstract

PURPOSE - The fundamental criterion for achieving an optimal aesthetic is surface colour. In dental ceramics many factors such as material type, surface specifications, number of firings, firing temperature and thickness of porcelain are important to provide an unaltered surface color. The aim of this study was to evaluate the number of firings on the colour stability of dental ceramics. MATERIALS AND METHODS - Metal ceramic crowns are selected as samples in the study, copings are designed in 3shape followed by wax milling and casting. Ceramic layer is added uniformly all over the coping (A2). After initial 2 firings, the crowns are kept for another 3 firings and after each firing, the color of each specimen was measured using a spectrophotometer (VITA EasyShade; VITA Zahnfabrik). RESULTS - When statistical analysis (one way ANOVA) was performed within 3 firings, a statistically significant difference was seen with the following: incisal (P =0.004), middle (P =0.001) and cervical (P = 0.044). CONCLUSION - Within the limitations of this in vitro study the following conclusions can be made, that with an increase in the number of firings it will lead to darker and more reddish / yellowish color.