Effects of different brands，color matching methods and enamel thicknesses on the color of double-layered resin composite restorations

Abstract:

Objective：To investigate the influence of different brands，enamel/dentin composite shade matching methods and enamel thicknesses on the color of double-layered resin composite restorations. Methods：Three brands of commercial resin composites（3M，Coltene，Kerr） were included in this study following two color matching methods：①Dentin color was the same with enamel color. ②Dentin color was 1unit darker than enamel color. Composite disk specimens with enamel thicknesses 0.0，0.5，1.0，2.0 and 3.0 mm were made（n=6）. The color of the specimens were assessed using a colorimeter and the color differences（ΔE） between the specimens and the VITA Classical Shade tab A2 shade were calculated. The results were analyzed by three-way analysis and Tukey’s test（P<0.05）. Results：With respect to the three composite brands，Coltene had the highest ΔE values and Kerr had the lowest ΔE values. ΔE values of color matching method 1 were significantly lower than those of color matching method 2. Enamel composite thickness of 0.5 mm was the lowest ΔE values and ΔE values were increased with the increasing of enamel thickness. Conclusion：Regarding to double-layered resin composite restorations with A2 shade，Kerr has the best results in matching the shade guide. The most color-matched method is the enamel shade and dentin shade with the same shade. The most color-matched enamel composite thickness to the shade tab is under 1.0 mm for Kerr and 3M.