Objectives: Color reproducibility refers to the ability of dental ceramics to accurately match the color of the selected shade tab without the aid of intrinsic or extrinsic colorants. The purpose of this in vitro study was to quantitatively evaluate the influence of different shades of esthetic resin composite core foundations, in addition to the shades of the luting resin cement on the final color of IPS Empress all-ceramic crowns. Methods: Ivoclar, Schaan Inc., Liechtenstein, provided the materials used in this study. A total of 128 disks were fabricated by means of a specially designed, metallic, disk-forming device; 64 (20.0 x 4.0 mm) were made of resin composite (Tetric Ceram), and 64 (20.0 x 1.0 mm) of IPS Empress all-ceramic material. The resin composite disks were further subdivided into four subgroups, 16 each, for the Vita shades (A3, B3, C3 and D3). The ceramic and resin composite disks were luted using Variolink II resin luting agent. Color was measured using a spectrophotometer (JASCO V570) configured with 45-degree/0-degree viewing geometry. Color observations were performed using a CIE 10-degree observer and CIE illuminant D65 with a data pitch 5 nm. The readings were analyzed via attached computer, and the CIE L*a*b* values were directly calculated. Descriptive statistical analysis for ΔL*, Δa*, Δb*, and ΔE values between the different color combinations was performed using SPSS software. Results: Statistically significant difference (p=0.033) was found between mean ΔE values:

Core Shades	n	Mean ΔE
A3 B3 C3 D3 Total	16 16 16 16 64	0.5±0.2 0.7±0.3 0.5±0.4 0.4±0.2 0.5±0.3

Tukey's post-hoc test showed significant difference (p=0.015) between B3 and D3 core combinations (ΔE=0.5). Conclusions: Within the limitations of this study, it was concluded that the combined effects of different core and resin luting agent shades on the final color of all-ceramic crowns were clinically undetectable (ΔE<1).