A rugosimetric study of four polishing protocols of a microhybrid composite resin

Background: Finishing and polishing a composite restoration are fundamental phases for clinical success. Choosing the right polishing protocol for the composite type is essential. The present rugosimetric study tests on a microhybrid composite resin the efficacy of 4 polishing protocols with rubber points or abrasive pastes with or without a superficial light-curing resin. Methods and Materials: Forty Filtek Z250 composite resin discs were prepared and divided into 4 groups of different decreasing grain polishing protocols: G1 rubber points; G2 abrasive pastes; G3 rubber points + Seal Coat Fast resin; G4 pastes + Seal Coat Fast resin. The specimens were analyzed using a rugosimeter considering linear (Ra: parallel, perpendicular, and oblique to the polishing direction) and surface (Sa) parameters. A 0,2 μm roughness value was assumed as clinically acceptable threshold. The collected data were statistically analyzed with Kruskal-Wallis and Mann-Whitney tests (C.I. 95%). Results: The 4 groups offered roughness mean values lower than 0,2 μm; generally G4 offered the lowest mean values; a not always statistically significant trend of roughness decrease was demonstrated with pastes. A difference was found for Sa: G1 vs G4 e G2 vs G4 (p<0,005), G3 vs G4 (p<0,05); Ra parallel: G1 vs G2 e G2 vs G4 (p<0,05); Ra perpendicular: G1 vs G2 e G3 vs G4 (p<0,05), G1 vs G4 e G2 vs G4 (p<0,001); Ra oblique: G1 vs G4 e G2 vs G4 (p<0,001), G3 vs G4 (p<0,005). Conclusions: The mean roughness values remained under the limit indicated by the literature in all groups. A decreased surface roughness of the Filtek Z250 was demonstrated by using abrasive pastes + Seal Coat Fast resin polishing protocol.