The Effect of repeated firing on the Color of Ceramic System with two Different Veneering Porcelain Shades

Statement of problem: Shade matching is an important property in fixed prosthodontics for achieving optimal esthetics. However, there is a lack of information on how color is affected by fabrication procedure. Purpose: To evaluate and to compare the color changes observed after repeated firing (3, 5 and 7) of Pressable ceramic system veneering with two different veneering porcelain shades using spectrophotometer. Materials and methods: Twenty disc-shaped ceramic specimens (10 mm in diameter, with a core thickness of 1 mm), with 2 different veneering porcelain shades (A1, B2), were fabricated from an Pressable ceramic system. Repeated firings (3, 5, and 7 firings) were performed. Color differences (ΔE) and changes in color parameters (ΔL, Δa, Δb) were determined using a spectrophotometer. The statistical analysis was done using Repeated-measures ANOVA. Unpaired ‘t’ and ‘Tukey HSD Post hoc test’ were used for multiple comparison. Results: The results denote that perceptible color changes (ΔE>1) were observed after repeated firing