Color Changes of Restorative Materials Exposed In Vitro to Cola Beverage

Purpose: The purpose of this in vitro study was to evaluate the color stability of restorative materials when exposed to a cola beverage. Methods: Color changes in restorative materials caused by exposure to a cola beverage were studied using a split-plot experimental design. Three restorative materials (composite, resin-modified glass ionomer cement, and compomer) and 3 shades of each material under 2 surface conditions (polished and unpolished) were studied. Using a chromameter, color changes were determined as the difference between color dimensions before and after cola exposure. Scanning electron microscopy was used to characterize the surface morphology of all materials before and after polishing. Results: 72-hour cola exposure resulted in significant changes in color, including gray level and chromaticity, both as a function of materials and their shades. Clinically, these changes compromised both color stability and esthetics in the resin-modified glass ionomer cement in all shades and in composites and compomers in the darkest shade. Conclusions: To avoid color degradation through cola, the lighter shades of composites and compomers should be favored over darker C shades to restore anterior and more visible lesions. Resin-modified glass ionomer cement is not recommended in esthetically critical areas due to its tendency to discolor due to cola exposure.