Color Stability and Stain Resistance of Composite Materials

Objectives: Investigate staining potential on composites from short and long-term exposure to green tea, coffee, red wine, and water.
Methods: 144 disc-shaped specimens, measuring 8x2mm, were prepared using 4 groups of composites (n=36): Group 1: Bioactive Flowable Composite with MCP (Pulpdent); Group 2: Filtek™ Supreme Ultra (3M); Group 3: Fuji II LC^® (GC America); and Group 4: Beautifil II^® (Shofu). Materials were prepared and cured (DEMI^™, Kerr) according to manufacturer’s instructions. All samples were wet-ground polished (EcoMet™250, Buehler) sequentially from coarse to smooth grit with final polishing done at 600 grit. Baseline color coordinates (L*, a*, b*) were then obtained and recorded using an Olympus Crystaleye Spectrophotometer. Samples from each group were submerged in each liquid for 3 weeks (n=9 per liquid). Color coordinates were taken after submersion for 1 day, 1 week, and 3 weeks. Changes in color (ΔE*) after each period were calculated using the baseline value as a reference.
Results: ΔE* tended to increase with length of submersion. There were statistically significant differences between groups, which depended on the beverage and length of submersion (see Tables 1-3). Results showed almost no significant differences in staining amongst the four groups after submersion in water over each period.
Conclusions: All the materials in this study displayed clinically unacceptable color changes at all times in red wine (ΔE* >8). Group 3 underwent the most color change after three weeks of submersion over time.