Influence of background shade and resin cement on color change of resin matrix ceramics

Introduction
Color stability of dental restorations is a major factor in achieving successful aesthetic outcomes. Objectives: The aim of the study was to evaluate the effect of resin cement and different composite resin background shades on the change of color of resin matrix ceramics (RMCs).

Material and methods
Three different RMCs were used in this study, including Vita Enamic (EN), GC Cerasmart (CS), and Lava Ultimate (LU). Ten specimens of each RMC with a dimension of 12 × 14 × 1 mm were prepared from CAD-CAM blocks, and 3 specimens from each RMC with a dimension of 12 × 14 × 4 mm were prepared as control group. Color measurements were performed on 3 different shaded (A1, A2, and A3) composite resin backgrounds. To evaluate the effect of resin cement, color differences between RMC specimens with and without resin cement were calculated. Data were analyzed by using two-way ANOVA and one-way ANOVA tests, with α = 0.05.

Results
In the groups with A2 and A3 shaded composite resin backgrounds, the highest color change values were observed in the EN group (p < 0.05). For all RMC materials, the highest color change values were observed in the specimens with A1 background (p < 0.05). The lowest color change after cementation was observed in the CS group (p < 0.05).

Conclusions
Composite resin background shades significantly affected the color of RMC materials. Color changes after cementation were above clinically acceptable level in all groups of specimens.