Effect of bleaching on surface roughness of two nanofilled and a microhybrid composite

Regarding the importance of surface roughness of tooth structure and restorative materials on plaque retention, this study was done to evaluate the effect of home and office bleaching agents on surface roughness of microhybrid and nanofilled composite resins. Point 4 (kerr, USA) microhybride composite, Premise (Kerr, USA) and Filtek supreme (3M ESPE, USA) nanofilled composites, Opalescence PF (Ultradent, USA) as the home bleaching agent and Opalescence Quisk (Ultradent, USA) as the office bleaching agent were selected. One hundred and fifty samples were divided into 15 groups (n = 10). For each composite, five groups were defined as: control, two weeks home bleaching, 4 weeks home bleaching, one time office bleaching and two times office bleaching with 2 weeks interval. The composites light cured under clear matrix strip and polished with soflex TM (3M ESPE, USA) polishing disks systems.After bleaching with specific protocol, surface roughness of samples was measured withprofilometer (SM7 Profile Test, Italy). The data were analyzed with two-way ANOVA statistical test. Surface morphology of samples were analyzed with scanning electron microscopy; SEM (XL30, Philips, Netherlands). There was no significant difference in surface roughness among all groups (p value > 0.05). There were no difference between the surface morphology of control and experimental groups of each composite. The bleaching agents used in this study had no effects on surface roughness of two types of nanofilled composites and one type of microhybrid composite.