Effect of firing on the color stability of a light-cured ceramic stain

Abstract

Purpose: This study evaluated the color stability of four stains of a light-cured porcelain stain system between the light-cured and fired stages. Materials and Methods: Thirty-six ceramometal discs 20 mm in diameter and 2 mm in thickness were cast to provide the substrate on which Ceramco II porcelain was applied. The porcelain was polished to a uniform thickness of 2 mm, and the samples were divided into four groups and assigned a color (yellow, orange, green, or blue). Orbit LC stain was applied in a thin layer and light-cured for 40 seconds. After light-curing, three color readings were made with a Minolta Chroma Meter II. The porcelain discs were then fired in a porcelain oven and three color measurements were again made. The pre- and postfired Commission Internationale de l'Eclairage L*a*b* values were recorded and the color difference (ΔE) was calculated for each specimen. The clinical significance for the computed ΔE ratings was completed according to previously modified criteria. Results: The results show that the mean ΔE between the light-cured and fired stages of Orbit LC are clinically acceptable. No statistically significant differences (p < .05) were observed between any of the four groups. Conclusions: A light-cured porcelain stain system was evaluated for color stability between light-cured and fired stages. Within the conditions of this study, the following conclusions can be made: (1) There was no clinically significant color difference between light-cured and fired stages for the stain colors evaluated; and (2) the final color of the restorations altered with light-cured stains can be predicted before firing. Copyright © 1996 by the American College of Prosthodontists.