Effect of esthetic core shades on the final color of IPS Empress all-ceramic crowns

Statement of problem. Clinically relevant assessment of all-ceramic crowns supported by esthetic composite resin foundations has not been evaluated with regard to color reproducibility. Purpose. This in vitro study quantitatively evaluated the influence of different shades of composite resin foundations and resin cement on the final color of a leucite-reinforced all-ceramic material. Material and methods. A total of 128 disks were fabricated; 64 (20 X 1 mm) were made of all-ceramic material (IPS Empress) and 64 (20 X 4 in in) of 4 different shades composite resin (Tetric Ceram). The ceramic and composite resin disks were luted using 2 shades (A3 and Transparent) of resin cement (Variolink II). Color was measured using a colorimeter configured with a diffuse illumination/0-degree viewing geometry, and Commission Internationale de I'Eclairage (CIE) L*a*b* values were directly calculated. Descriptive statistical analysis was performed, and color differences (Delta E) for the average L*, a* and b* color parameters were calculated. Repeated measures analysis of variance (ANOVA) was used to compare mean values and SDs between the different color combinations (alpha=.05). Results. The CIE L*a*b* color coordinate values showed no significant differences for variation in color parameters due to the effect of the different composite resin shades (P=.24) or cement shades (P=.12). The mean color difference (Delta E) value between the groups was 0.8. Conclusion. Within the limitations of this study, the use of different shades for composite resin cores and resin cements presented no statistically significant effect on the final color of IPS Empress all-ceramic material.