The Effect of Different Storage Media on Color Stability of Self-Adhesive Composite Resin Cements for up to One Year

The aim of this study was to analyze the long-term color stability of eight self-adhesive composite resin cements (SACRCs) after storage in diverse media for up to one year. 480 discs (diameter: 12 mm/thickness: 1.0 +/- 0.05 mm) were fabricated (n = 60/SACRC): (1) BeautyCem (BEA);(2) Bifix SE (BIF);(3) Clearfil SA Cement Automix (CLE);(4) RelyX Unicem 2 Automix (RXU);(5) SeT (SET);(6) SmartCem 2 (SMC);(7) SoloCem (SOC);and (8) SpeedCEM (SPC). After polishing, specimens were immersed in (a) red wine (RW);(b) curry-solution (CU);(c) cress-solution (CR);and (d) distilled water (DW) at 37 degrees C and measured after 7, 28, 90, 180, and 365 days for color differences (Delta E) and water absorption (WA). Non-aged specimens were used as baselines. After 365 days, all of the discs were polished and their Delta E was measured. Data were analyzed using Kolmogorov-Smirnov, partial-eta-squared/eta(2)(P), 3-/1-way ANOVA with Tukey-HSD post-hoc test (alpha = 0.05). Significant differences occurred between all SACRCs for WA (p <= 0.003), except in RXU and in SET and in Delta E (p <= 0.002), except in SET and SPC. The significantly highest WA presented in SOC;the lowest showed in BEA. Significant Delta E differences and a decrease after polishing between all storage media were found (p < 0.001) with highest values for RW, followed by CU, CR, and DW. The lowest Delta E was measured for CLE, followed by SOC, BIF, RXU, BEA, SPC, SET, and SMC (p < 0.001) and increased significantly during aging. The highest Delta E decrease presented in BEA. SACRCs showed an increase in WA/Delta E within total aging time. Discoloration could not be removed completely by polishing. SACRCs need to be carefully selected for restorations in the esthetical zone with visible restoration margins. Polishing can significantly reduce the marginal discoloration