Influence of ceramic laminate on water sorption, solubility, color stability, and microhardness of resin cements

Purpose: To evaluate the influence of ceramic laminate on color stability, surface microhardness, water sorption, and solubility of resin luting agents. Methods: Disk-shaped specimens (10 x 2 mm) of dual-cured resin cements (RelyX ARC or RelyX Ultimate) were obtained, and a light-cured luting agent (RelyX Veneer) was used. In Experiment 1, disk-shaped resin cements (n = 10) were submitted to: I) polymerization with or without ceramic laminate (0.7 mm), and II) immersion in distilled water or coffee, 3 hours daily for 20 days. The surface microhardness loss (%SML) was determined, and the color variables were assessed by the CIE L*a*b* system (Delta E, Delta L*) and the shade guide units (Delta SGU). In Experiment 2, other disk-shaped specimens (n = 5) were submitted to polymerization with or without ceramic laminate to assess their water sorption (WS) and solubility (S). Statistical analysis was performed using 3-way ANOVA and Tukey's test for Delta E, Delta L* and %SML; Mann-Whitney, Kruskal-Wallis, and Dunn's tests for Delta SGU; and 2-way ANOVA and Tukey's test for WS and S. The significance level was set at 5%. Results: No statistically significant differences among the resin cements was observed for %SML, WS, or S, regardless of stain exposure or presence of ceramic laminate during light activation. Coffee caused a significant decrease in Delta L* values. All the resin cements presented visually detectable color alteration for Delta E; however, RelyX Ultimate showed less color change after coffee exposure. RelyX ARC showed the greatest color change in water. RelyX Veneer presented the highest values of Delta SGU, compared with the other resin cements. The WS, S, and %SML of resin cements were not influenced by the staining solution or the presence of ceramic laminate during light activation; however, RelyX Ultimate resin cement presented the best color stability.