Color stability of dental ceramics submitted to artificial accelerated aging after repeated firings

Statement of problem Color stability is an important factor to ensure the long-term clinical success of ceramic restorations. There is a lack of information on how color is affected by fabrication procedures, such as the number of firings. Purpose The purpose of this study was to evaluate the effects that the number of firings and type of substrate have on the color stability of dental ceramic submitted to artificial accelerated aging. Material and methods Sixty specimens were fabricated: 30 metal ceramic (Verabond II + IPS d.SIGN) and 30 all-ceramic (IPS d.SIGN). Specimens were divided into 3 groups (n=10), and submitted to 2, 3, or 4 firings (±900°C), respectively, according to the manufacturer's instructions. Color readings were obtained with a spectrophotometer before and after artificial accelerated aging, and L*, a*, and b* coordinates and total color variation (ΔE) were analyzed (2-way ANOVA, Bonferroni, α=05). Results For metal ceramic specimens, differences for the L* coordinates were significant ( P