Rugosimetric analysis of flowable composites after aluminum oxide paste polishing

Objectives: Clinicians require simplified and effective protocols in order to polish composite resin restorations. Flowable composites have been advocated for small occlusal restorations. The present analysis evaluates the surface roughness of 4 flowable composites polished with a recently introduced one step aluminum oxide paste. Methods: Twenty discs per composite were polymerized under a mylar strip: Filtek Supreme XT flow (3M ESPE, USA) (group 1 = G1); Dyract flow (Dentsply Caulk Mildford, USA) (group 2 = G2); Tetric flow (Ivoclar, Germany) (group 3 = G3); Premise flow (Kerr, USA) (group 4 = G4). Ten discs per group were finished with 1200 grit sandpaper and polished with Nupro Shimmer paste (Dentsply Caulk Mildford). Specimens were stored in artificial saliva for 24h and then underwent a profilometric analysis; a threshold value of 0.20 µm was assumed. Rugosimetric data were statistically analyzed with parametric tests (p<0.05). A qualitative SEM evaluation of specimens was carried out. Results: Ra mean values ±SD (µm) of polished specimens were: G1, 0.07 ±0.01; G2, 0.08 ±0.02; G3, 0.05 ±0.01; G4, 0.04 ±0.01; control mylar values were: G1, 0.03 ±0.01; G2, 0.16 ±0.07; G3, 0.04 ±0.01; G4, 0.05 ±0.01. Mean roughness was significantly lower in mylar than in polished specimens in G1 and G3, whereas greater in G2; mylar and polished specimens showed similar surface roughness in G4. No statistically significant difference was found between G1 vs G2 and G3 vs G4 for polished specimens. SEM analysis showed smooth surfaces in all groups. Conclusions: Flowable composite polishing with Nupro Shimmer lead to roughness mean values lower than the established threshold value in all groups. Best results were achieved with Tetric and Premise flowable composites.