Color stability of CAD/CAM interim material for long-term fixed dental prostheses vs. conventional materials after immersion in different staining solutions

Abstract

The color stability of interim computer-aided design and computer-assisted manufacturing (CAD/CAM) materials has not been exhaustively investigated. The aim of this study was to com- pare the translucency (TP) and contrast ratio (CR) of CAD/CAM blocks and conventional interim materials, as well as the effects of varnish application and tooth-brushing on color stability after immersion in different staining solutions. Four hundred and eighty specimens were fabricated with four different interim materials (n = 120) and were divided into three experimental, and one control group (n = 30). The color measurements were taken at the initial time (T0), 24 h (T1), 7 days (T2), and 30 days (T3) after immersion in different solutions. CIEDE2000 (∆E00) values were analyzed with ANOVA and Fischer's LSD test with a 95% confidence interval. The relationship between TP and CR was analyzed with a Pearson correlation. All interim materials showed a significant difference (p < 0.05) in color change after 30 days. Results showed that polyethyl methacrylate resins (PEMA) had the highest stability over time. The TP and CR were statistically significant (p < 0.05). It was observed that brushing improved the color stability but the ∆E00 were the highest when the varnish alone or varnish and brushing were used, except in the bis-acryl group, in which varnish and brushing decreased the color stainability.