Abstract:
Objective: The aim of this in vitro study was to examine the color changes in resin cements polymerized under lithium disilicate glass ceramic material (IPS Empress 2).
Material and methods: A pressable ceramic material (10 mm x 1 mm) placed between the curing unit tip and resin cement was used to simulate the impact of light transmission on restoration. Light-polymerized Variolink II, dual polymerized Variolink II, Multilink Automix, Clearfil Esthetic Cement, Panavia F 2.0, RelyX Veneer, and Nexus 3 resin cement specimens were polymerized by a high-power light-emitting diode curing unit (Demi). A spectrophotometer (Vita EasyShade) was used to measure the colorimetric values of the specimens. Color changes were determined by the CIEL*a*b color system. Total color differences (Delta E-ab*) of the resin cement specimen with or without the ceramic specimen were calculated. Analysis of variance, Tukey's honestly significant difference and paired t-tests were used to analyze the data (a = 0.05). Results: There were significant differences among Delta E-ab* values with or without the ceramic specimen (p < 0.05). The light-polymerized Variolink II resin cement specimens induced the greatest color changes with or without the ceramic specimen (Delta E-ab* = 14.21 and Delta E-ab* = 2.32). The Delta E-ab* values of all resin cements with the ceramic specimen were less than 2.5 and the Panavia F 2.0 specimens induced the smallest color changes (Delta E-ab* = 0.95). Conclusions: Light polymerization of resin cements is a significant factor affecting the color of the final restoration, but lithium disilicate glass ceramics of 1-mm thickness appeared to have a masking effect on the color changes in resin cements.
