Color accuracy of resin cements and try-in pastes.

The color accuracy of resin composite cements and their corresponding try-in pastes was assessed. Three shades of three brands were compared using the cements alone and in contact with a standard porcelain disk. There were significant differences in color between resin cements and their corresponding try-in pastes. The addition of a 1-mm-thick porcelain disk greatly reduced the apparent color differences. The color of resin cements changed over time, but not significantly. Baseline measurements of resin cement colors were compared and measurements made after 24 hours of storage. Color changes were statistically significant but not perceptible, and all samples became slightly darker with age.