Objectives:
The aim of the study was to evaluate, in vitro, the surface roughness and microhardness of two different composite resin materials submitted to simulated tooth brushing with activated charcoal and calcium carbonate toothpastes.

Materials and Methods:
Microfilled (Heliomolar) and nanohybrid (Tg-nanohybrid) composite resins were studied, 30 disc-shaped specimens were prepared from each composite, then divided to 3 groups (n=10); group A (control group): brushed with distilled water, group B: brushed with Perfect white (Black)® toothpaste group, and group C: brushed with Depurdent® toothpaste, with a powered toothbrush for 30 seconds daily for 7 days. Vickers Microhardness was measured at 10N load and the surface roughness was measured using a surface roughness tester, SEM examination of some selected samples after brushing was conducted. Two-way analysis of variance (ANOVA) and Kruskal-Wallis were used to analyze the data with 5% level of significance between the means of tested groups.
Results:
The two composites showed significant increase in surface roughness after brushing in all groups, the highest values occurred in nanohybrid/Depurdent group, while the lowest values were in microfilled/control group. Microhardness increased significantly in nanohybrid/Depurdent group and decreased in microfilled/Depurdent group, while no significant change in microhardness was noted after brushing with Perfect white (Black) in both composites compared to the control group.
Conclusion
The tested dentifrices significantly influenced the surface roughness and microhardness of microfilled and nanohybrid composite resins.