Color stability and aging of plastic veneering materials.

The color stability and aging characteristics of commercial plastic veneering materials were studied in vitro by an accelerated aging method. Values of luminous reflectance, dominant wavelength, and excitation purity at baseline were similar to values reported for composite restorative materials. The veneering materials were more opaque than composites. After aging for 900 h, small changes in color were observed instrumentally, but were difficult to detect visually. Weight loss of some the veneering materials after aging was greater than that anticipated from solubility in water alone.