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

EH Ismail; DV Dawson; CMP Vidal; FN Skiff; K Brogden; RR Maia

doi:10.2341/21-138-L

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Article Contents

SUMMARY
INTRODUCTION
METHODS AND MATERIALS
RESULTS
DISCUSSION
CONCLUSIONS
Acknowledgments
REFERENCES

Editorial Type:

Article Category: Research Article

Online Publication Date: 15 Dec 2022

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

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Page Range: 68 – 78

DOI: 10.2341/21-138-L

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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.

Figure 1.

Enamel and dentin layer specimens. Nine subgroups per resin composite system (n=7 per subgroup) (A) Clearfil Majesty (CM) and (B) Vit-l-escence (VL). Enamel shade for CM: A2E and for VL: Pearl Neutral (PN) with thickness of (0.5, 0.7, 1.0 mm). Dentin shades for both CM and VL are A1, A2, A3. Note that as the enamel layer thickness increases, the enamel layer translucency decreases. Additionally, dentin samples decrease in size.

Figure 2.

Bar chart illustrating the means of Chroma (C*) of the dentin layer and double layered (DL) specimens for Clearfil Majesty (CM). One-way ANOVA with the Tukey post-hoc comparison revealed the means of chroma of the dentin layer (indicated by different uppercase letters) designate statistical differences among the nine subgroups of dentin layers (α=0.05) (p<0.001). However, means of C* of DL specimens did not differ significantly among the nine subgroups (p=0.65).

Figure 3.

Bar chart illustrating the means of Chroma (C*) of the dentin layer and the double-layered (DL) specimens for Vit-l-escence (VL). One-way ANOVA with the Tukey post-hoc comparison revealed the means of C* of the dentin layer (indicated by different uppercase letters) designate statistical differences among the nine subgroups of dentin layers (α=0.05) (p<0.001). However, means of C* of DL specimens did not differ significantly among the nine subgroups (p=0.53).

Figure 4.

Box plots depicting the distribution of color differences, ΔE₀₀, relative to the A2 shade tab for nine treatment combinations (three dentin layering shades × three enamel thicknesses) for fabrications using the CM RC resin brand.