A Comparative Analysis of Color Stability in Direct and Indirect Restorative Materials Following Immersion in a Coffee Solution.

Introduction: This study aims to determine the color stability of direct and indirect restorative materials after immersion in coffee solution. Materials and Methods: A total of 32 blocks (12 mm × 10 mm × 2 mm) were prepared from four tested materials; feldspar ceramic (VITABLOCS Mark II: Vita Zahnfabrik, Germany), hybrid ceramic (Vita Enamic: Vita Zahnfabrik, Germany), indirect composite resin (Gradia Indirect: GC, Japan), and direct composite resin (G-aenial anterior: GC, Japan). The color of all specimens was measured by a spectroradiometer using CIELAB color space before and after thermocycling (5000 cycles) followed by immersion in coffee solution. The color difference (ΔE) was calculated by measuring L ∗ , a ∗ , and b ∗ color values. Data were analyzed using ANOVA and post hoc tests at the significant level of 0.05. Results: All materials tested exhibited unacceptable color changes after immersion in the coffee solution. The highest value of color change (ΔE) was reported for the Gradia Indirect composite, followed by the Vita Enamic and G-aenial and VITABLOCS Mark II groups, respectively. However, no significant differences were observed between any of the groups (p = 0.058). G-aenial showed the most visual discoloration. Conclusions: The study demonstrated that there were no statistically significant differences in color change between the various groups following immersion in coffee. Additionally, the color change exceeded the clinically acceptable limit in all samples. It is noteworthy that differences in the initial color values (L ∗ , a ∗ , and b ∗ ) resulting from the different compositions and structures of the materials may influence visual perception.