Effect of Autoclaving on the Action of Polishing Systems on the Surface Roughness of a Composite Resin

The purpose of the study was to evaluate the effect of autoclaving one-step polishing systems on the surface roughness of a nanoparticle resin composite. Sixty disk-shaped specimens were fabricated （0 12 mm and 2.5 mm height） with Tetric N-Ceram （IvoclarVivadent）. Thirty discs were polished with brushes （Astrobrush, IvoclarVivadent）and the other 30 discs with rubber tips （Optrapol, Ivoclar Vivadent）. The specimens were divided into 6 groups （n = 10）, according to the association between polishing system and number of autoclave cycles： G1, Astrobrush used for first time and without autoclave （control）; G2, Astrobrush used after the 10th autoclave cycle; G3, Astrobrush used after the 20th autoclave cycle; G4, 0ptrapol used for first time and without autoclave （control）; G5, Optrapol used after the 10th autoclave cycle; G6, Optrapol used after the 20th autoclave cycle. The surface roughness （Ra） of each specimen and the data was used for analysis of variance （ANOVA）. There was no significantly statistical differ