Color Stability of Simplified Shade Resin Composite Systems

Objectives: The aim of this study was to evaluate the color stability of simplified shade resin composite systems after staining, as well as the color recovery after repolishing.
Methods: Cylindrical specimens (6 mm diameter and 1 mm thickness) were made with different resin composites (n=15/group). The tested materials were a conventional multishade system (positive control): Grandioso-Voco (Gnd); single shade systems: Vittra APS Unique-FGM (Vit), Palfique Omnichroma-Tokuyama (Omn), Charisma-Kulzer (Char); and simplified systems: Admira Fusion 5-Voco (Ad5), Tetric Prime-Ivoclar Vivadent (Tet), Spectra ST HV-Dentsply (Spt), G-aenial A’Chord-GC (G-ae), and Filtek Universal-3M/ESPE (Fil). The specimens were polished, and baseline color was assessed with a colorimetric spectrophotometer (CM-5, Konica Minolta) according to the CIELAB system. Next, they were immersed in a staining solution for 14 days, followed by a second color assessment. Afterward, the specimens were repolished, and a third color measurement was taken. The variation in color coordinates (ΔL, Δa, and Δb) was calculated, and the overall color alteration was determined compared to baseline (ΔE00-1 after staining and ΔE00-2 after repolishing). Data were submitted to ANOVA/Tukey tests (5%).
Results: Mean ± SD for ΔE00-1 were: Gnd (1.52 ± 0.65)a; G-ae (1.73 ± 0.44)a; Spt (1.73 ± 0.88)a; Ad5 (1.89 ± 0.30)a; Omn (3.65 ± 0.65)b; Fil (4.02 ± 0.55)bc; Char (4.51 ± 0.61)bc; Tet (4.98 ± 1.83)bc; Vit (5.09 ± 1.07)c. For ΔE00-2: Spt (0.94 ± 0.46)a; Gnd (1.05 ± 0.55)a; G-ae (1.15 ± 0.49)a; Ad5 (1.17 ± 0.39)a; Fil (1.29 ± 0.79)a; Tet (2.97 ± 1.39)b; Omn (3.46 ± 0.76)b; Char (3.72 ± 0.77)b; Vit (3.65 ± 0.86)b. Different letters mean significant differences (p<0.05).
Conclusions: Conclusion: The color stability was material-dependent, with Grandioso, G-aenial, Spectra, and Admira Fusion 5 showing the least color alteration after staining. Repolishing reduced the staining effects for all materials.