The Effect of Varying Dentin Chroma and Enamel Thickness on the Color of A2 Double-layered Resin Composite

Abstract

SUMMARY Objectives To evaluate chroma (C*) and overall color of double-layered (DL) resin composite (RC) restorations with various dentin shades and enamel thicknesses. Methods Enamel specimens were fabricated using custom-made molds to replicate VITA shade tabs with variant enamel thicknesses (0.5, 0.7, and 1.0 mm) (n=7) from two RC: Clearfil-Majesty (CM) shade (A2), and Vit-l-escence (VL), shade (pearl-neutral). Dentin specimens (shades A1, A2, and A3) were fabricated using custom molds corresponding to the enamel molds. Each enamel specimen was paired with three different dentin specimens. L*a*b* parameters were measured with VITA Easyshade-V. Color difference between DL specimens and the A2 VITA shade tab were calculated with the CIEDE2000 formula. Relationships among enamel thickness, ΔE00, C* of dentin layer, C* of DL, and change in chroma were assessed by Spearman rank correlations. ΔE00 was compared among groups using one-way analysis of variance with Tukey post-hoc adjustment for all possible pairwise group comparisons (experiment-wise α=0.05). Results There was no statistical difference among C* of DL specimens (p=0.65, 0.53) for CM and VL, respectively. Combinations of enamel thickness/dentin shade had a significant difference in ΔE00 (p>0.05). No significant correlation was observed among enamel thickness and C* of dentin, and C* of the DL (p>0.05). Significant correlations were observed between ΔE00 of the VL DL and C* DL (r=−0.8, p<0.001); and ΔE00 of CM DL and enamel thickness (r=0.5, p<0.001). Conclusions Enamel thickness did not affect C* of the dentin layer. Unlike VL RC, variations in dentin shades with CM produced a closer match to the A2 shade tab. Enamel is recommended to be 0.7 mm or less.