Influence of Different Bleaching Agents on Surface Roughness of Composite Resins Filling

The aim of this study was to evaluate the effects of one in-office and two home bleaching agents on the surface roughness of a hybrid, microhybrid and nanohybrid composite resin. Three composite resins (Valux Plus, 3M ESPE, Filtek Z 250, 3M ESPE, and Herculite XRV Ultra, Kerr) and three bleaching agents (Opalescence PF, Ultradent Products, Perfect Bleach, Voco, and Perfect BleachOffice +, Voco) were chosen for this study. Twenty eight samples of each composite resin were prepared and were equally split in 4 groups: 7 samples were stored in distilled water (control group), 7 samples were subject to 17% carbamide peroxide gel (Perfect Bleach) action for 3 h a day, 7 days, 7 samples were subject to 15% carbamide peroxide gel (Opalescence PF) action for 3 h a day, 7 days and 7 samples were subject to 35% hydrogen peroxide gel (Perfect BleachOffice +) action two times for 15 min . After cleaning the samples were submitted to roughness evaluation using atomic force microscopy (AFM). Bleaching agents that contain 35% hydrogen peroxide and 17% or 15% carbamide peroxide increased the composite resins surface roughness. The hybrid resin recorded the highest roughness after bleaching, followed in descending order by microhybrid and nanohybrid composite resins.