The Effect of Restorative Material Type, Thickness, Curing Mode, and Post-Irradiation Time on the Degree of Conversion of a Dual-Cure Resin Cement

This in vitro study evaluated the effects of restorative material type, thickness, curing mode, and post-irradiation time on the degree of conversion (DC) of a dual-cure resin cement. Specimens of VITA Suprinity (VS), VITA Enamic (VE), Lava Ultimate (LU), and Saremco Print Crowntec (SC) were prepared at thicknesses of 1.0 and 1.5 mm. A dual-cure resin cement was placed beneath each specimen and light-cured through the specimen using a VALO X curing light in Standard Power (SP) or Xtra Power (XP) mode (n = 8). DC was measured by FT-IR/ATR spectroscopy at days 1 and 10. The normality and homogeneity of variances were assessed using the Shapiro–Wilk and Levene tests, and data were analyzed using mixed-design repeated-measures ANOVA and Tukey HSD tests (α = 0.05). Material type and thickness significantly affected DC (p < 0.001), whereas curing mode did not (p = 0.110). Post-irradiation time significantly affected DC (p < 0.001), and a significant material–thickness interaction was found (p = 0.043). Within the limitations of this study, DC was affected by material type, thickness, and post-irradiation time, but not by curing mode.