Objective: This in-vitro study aimed to evaluate the effects of ceramic thicknesses and translucencies as well as resin cement shades on the masking ability of zirconia based lithium silicate discs (ZLC).
Materials and Methods: Eighty-four ceramic discs were manufactured from high translucent (HT) and translucent (T) ZLC ceramic. Discs were divided into three equal subgroups, according to their thickness (0.5, 1, 1.5 mm). Background composite resin discs (shade C4D) were used to simulate the color of dark abutments. Ceramic discs were cemented to composite ones with either translucent or opaque resin cements. Color parameters were measured using a spectrophotometer and recorded by CIELab system, color difference between ceramic discs and cemented ceramic discs to composite were calculated as E. All data were statistically analyzed, using unpaired-t test, ANOVA test and Tukey HSD test. Statistical significance was set at p < 0.05.
Results: A statistically significant color difference (E) was found between (HT) and (T) discs (P<0.05). E values of both translucencies were affected by ceramic thickness (P=0.000). Resin cement shade had no significant effect on E values when the thicknesses of ceramic veneer were 1.0 mm or 1.5 mm (P values=0.495 and 0.265 respectively). While the cement shades had a highly significant effect on E values when ceramic, disc thickness was 0.5mm. (P value<0.0001).
Conclusion: As the veneer thickness increased, color change decreased significantly. Ceramic translucency and cement shade significantly influence the final color of pressable ZLC veneers only if the thickness is less than 1 mm.