Color stability of ionomer and resin composite restoratives

This study compared the color stability of a conventional glass ionomer (Ketac-Fil), a light polymerized resin-modified glass ionomer (PhotacFil), a polyacid-modified resin composite or compomer (Dyract) and a microfilled resin composite (Silux Plus). Thirty-two specimens (n=8/material) were fabricated and stored in artificial saliva at 37 degreesC for seven weeks. A colorimetric evaluation, according to the CIE L*a*b* system, was performed at 24 hours (baseline) and at the end of each week. Color difference values (DeltaE*ab) were calculated. The conventional glass ionomer, resin-modified ionomer and compomer materials underwent significant color changes over time (p<0.01). Those materials darkened and showed color shifts in both the red-green and yellow-blue axes.