Effect of brand and shade of resin cements on the final color of lithium disilicate ceramic

Abstract

Statement of problem. Resin cements are available in various shades from different manufacturers. However, there is no standard for the optical properties of these cements, which may result in differences in the color of translucent ceramic restorations.

Purpose. The purpose of this in vitro study was to evaluate the effects of different shades and brands of resin cements on the color of a lithium disilicate ceramic.

Materials and methods. Ten ceramic disks (11x1.5 mm, shade A2) were fabricated from lithium disilicate high-translucency blocks. Eighty cement disks (11x0.2 mm) were fabricated from 4 brands (Maxcem; Variolink; Clearfil; and RelyX) of resin cements in translucent and universal (shade A2) shades. Color measurements of ceramic specimens were made without (control) and with each brand/shade of resin cement material (test) with a spectrophotometer, and International Commission on Illumination Lab (CIELab) color coordinates were recorded. Color differences (Delta E-00) between the control and test groups were calculated. Delta E-00 results were analyzed by 2-way ANOVA and subsequent pairwise testing. Comparisons were performed using the Student t test, and then all P values were corrected with the step-down Bonferroni procedure (alpha=.05).

Results. The effect on the Delta E-00 values (P<.001) of the brand and shade of resin cement materials was significant. Both shades of RelyX cement groups had significantly lower and Variolink_translucent cement group had significantly higher Delta E-00 results than other brands (P<.05). Only RelyX_translucent and RelyX_universal were significantly different from each other for comparisons within brands (P<.05). The effect of RelyX_universal cement on the ceramic was not visually perceptible (Delta E-00 <= 1.30). Clinically unacceptable results (Delta E-00>2.25) were observed only for Variolink_translucent cement (2.36).

Conclusions. Same-shade resin cements from different manufacturers had different effects on the color of lithium disilicate ceramic. The effects of different shades of resin cements from the same manufacturer on the color of lithium disilicate ceramic were statistically different for only RelyX, which may also be considered clinically different based on clinical acceptability thresholds for color difference values (Delta E-00). Accordingly, this effect may be considered clinically different for Variolink but not clinically different for Maxcem and Clearfil.