Color Stability of Indirect Composites Luted With Dual-cured Resin Cements

Methods: Three different indirect composites were prepared in the study (Ceramage/Shofu, Estenia C&B/Kuraray Noritake, Gradia Forte/GC). 2.0-mm thick indirect composites with attaching tape were placed on zirconia (groups without cement, each n=3), or they were luted with dual-cured resin cements (ResiCem/Shofu, Clearfil Esthetic Cement/Kuraray Noritake, G-CEM LinkAce/GC) on zirconia (groups with cement, each n=3). The indirect composites and the dual-cured resin cements were obtained from the same manufacturer. Specimens were stored in dark box at 37ºC for 24 h. Color measurements were performed using a spectrophotometer before and after immersion in deionized water at 37ºC in dark condition for 4 weeks. Change in color (ΔE^*, before and after immersion) were obtained using the CIE L^*a^*b^*system. The results were analyzed by one-way ANOVA, and identical letters indicated no significant differences in post-hoc Tukey’s compromise test for each factor (p>0.05).

Results: All indirect composites luted with or without dual-cured resin cements showed varying changes in color. The ΔE^*s of the groups ranged from 0.26 to 1.13. The highest discoloration was attributed to Ceramage without cement, while the lower discoloration was found in Estenia C&B luted with Clearfil Esthetic Cement.

Conclusions: All indirect composites luted with resin cement evaluated were considered clinically acceptable (ΔE^*<3.3). Dual-cured resin cements may not affect color stability of 2.0-mm thick indirect composites.