surface roughness of different composite resins after application of 15% carbamide peroxide and brushing with toothpaste: an in-vitro study

Objectives: this study aimed to evaluate the effect of toothbrushing after application of 15% carbamide peroxide (cp) on the surface roughness of three types of composite resins. materials and methods: twenty samples, measuring 4 mm in height and diameter, were fabricated of three composite resins namely microfilled (mf) heliomolar hb, nanohybrid (nh) ips empress direct and microhybrid (mh) tetric ceram hb. after polishing, the initial surface roughness was measured with a profilometer. the tray technique was used to apply 15% cp gel for 6 hours. then, cleaning was carried out with an oral-b electric toothbrush for 3 minutes in a tank containing a freshly mixed toothpaste. these procedures were repeated for 21 days. then, the surface roughness was measured again and compared with the initial values. a mixed-design anova model was used for the analysis of data (p<0.05). results: the baseline roughness was significantly lower in mf compared to the nh and mh composites (p<0.001). roughness increased in all study groups during the intervention period; however, this increase was not significant in the mh group (p=0.17). furthermore, the increase in roughness in mf was smaller than that in nh (p<0.001) and mh (p=0.02) groups. conclusion: the effect of intervention was more pronounced on nh and mh groups. surface roughness changes were minor in mf composite resin.