Color Stability and Staining of Dental One-Shade Composites

Objectives: One-shade resin composites simplify the shade-selection process and may reduce costs and treatment efforts. Besides color adaption and matching, maintaining the visual appearance over time is critical. The objective of this study was to analyze color stability and susceptibility to discoloration of one-shade resin composites.
Methods: Color stability and staining of four different one-shade composites was investigated; Admira Fusion x-tra (Voco, Cuxhaven, Germany), Venus Diamond ONE (Kulzer, Hanau, Germany), Omnichroma (Tokuyama, Tokyo, Japan), Ecosite ONE (DMG, Hamburg, Germany). Color stability was measured after storage at 37°C in distilled water for 14 days (n=3/groups). Staining was examined in separate test setups after storage in coffee and red wine at 37°C for 14 days each (n=3/group). Color differences between start (t₀) and end (t₁) of storage were evaluated with a spectrophotometer (CM-36dGV, Konica Minolta, Marunouchi, Japan) and compared in each case using the CIE-Lab system with ΔE=√((L^*₁-L^*₀)² + (a^*₁-a^*₀)² + (b^*₁-b^*₀)²). Statistical analysis was done using non-parametric Kruskal-Wallis-Test for differences between groups and Dunn-Bonferroni-Test for pairwise comparison with a type I error level of 0.05.
Results: Color differences (ΔE) after storage in water for 14 days varied significantly between the groups (p=0.024) and were most pronounced for Admira Fusion x-tra (Median±IQR; 7.13±0.66), followed by Omnichroma (3.38±0.05), Venus Diamond ONE (1.28±0.55) and Ecosite ONE (0.89±0.07). Most of the color change of Admira fusion x-tra and Omnichroma could be attributed to changes in the b*-value, indicating visually perceptible yellowing of the material. Staining in coffee and red wine resulted in significant differences between the materials (coffee: p=0.019, red wine: p=0.025) with Ecosite ONE showing the smallest ΔE for both storage media.
Conclusions: Significant differences in color stability and resistance to discoloration were observed between the one-shade composites, with Ecosite ONE and Venus Diamond ONE demonstrating color stability below the clinically perceptible range.