Effect of shade and opacity on color differences and translucency of resin composite veneers over lighter and darker substrates.

To evaluate color differences (ΔE) and translucency parameters (TP) from mono, bi, and trilayer resin composite veneers using different opacities and shades of resin composite over lighter and darker simulated tooth-colored substrates. Mono, bi, and trilayer veneers (1.5 mm) (n = 12) were made using two shades (A1 and A2) and three opacities (enamel, body, and dentin) of resin composite over simulated lighter (A1) and darker (C4, and C4+) tooth-colored substrates. CIEDE2000 formula was used to calculate ΔE considering simulated tooth-colored substrate versus opacities in distinct mono, bi, and trilayer combinations of resin composite over the simulated tooth-colored substrate. The TP was calculated using color coordinates measured over standard white and black backgrounds. Differences in ΔE and TP values were calculated with a Three-way Analysis of Variance followed by Tukey's post-hoc test. A1E and A1B monolayer veneers showed similar TP values. Significantly higher ΔE values were observed over darker (C4 and C4+), and lower over lighter (A1) simulated tooth-colored substrate. Bilayer and trilayer veneers using dentin opacity provided similar ΔE values over the darker tooth-colored substrate. Distinct shades and opacities of resin composite layer combinations over lighter and darker tooth-colored substrates significantly affected TP and ΔE values. A1 shade and dentin opacity of monolayer resin composite veneers yielded higher ΔE values over darker tooth-colored substrates.