Objectives: To compare in vitro the color stability of one nanohybrid and one microhybrid composite restorative materials and correlate with surface roughness following different surface treatment protocols.
Materials and Methods: 150 specimens of each composite type were fabricated. The specimens were divided into five groups according to finishing/polishing technique, 30 specimen each. Surface roughness values (Ra) of each specimen were measured five times, and mean Ra values were determined. Baseline color measurements were made with a Vita Easy shadeV. Each group was then divided into three subgroups of 10 specimens each according to storage media, specimens of each subgroup were stored for 7 days in distilled water, black coffee, or black tea respectively. The specimens were then rinsed with distilled water and dried before the second color measurement.
Results: No significant difference in surface roughness among the two types of composite resins regardless the method of finishing & polishing used. Additionally, no statistically significant correlation between the surface roughness and the color difference values.
Conclusion: Intra-orally, composite surface discoloration might happen with extremely smooth surface and not always related to the degree of surface roughness.
Proper finishing and polishing of composite restorations will reduce but not totally prevent the color change caused by coloring beverages.