Effect of different powers of Er,Cr:YSGG laser treatment on surface morphology of microhybride composite resin: scanning electron microscope [SEM] evaluation

Introduction: The aim of this study was to evaluate and compare microhybride composite treated by bur and different power of Erbium, Chromium doped Yttrium Sc and ium Gallium Garnet [Er, Cr:YSGG] laser by Scanning Electron Microscope [SEM]. Methods: 21 microhybride composite blocks [DiaFil TM, DiaDent, Korea] with 2 × 4 × 4 mm dimensions were made. The bonding surface of these blocks were polished, The samples were put into 6 groups for laser irradiation as follows: Group 1 [power: 1W, Energy: 50 m/l]; Group 2[power: 2 W, Energy: 100m/l]; Group 3 [power: 3W, Energy: 150m/l]; Group 4 [power: 4W, Energy: 200m/l]; Group 5 [power: 5W, Energy: 250m/l] and Group 6[power:6 W, Energy:300m/l]. One group prepared by bur- treated. All samples were prepared by repetition rate of 20 Hz. Then, the samples were prepared for SEM examination. Result: Some irregularities were seen in Er, Cr:YSGG laser samples in comparison to Bur group that produced favorable surface for adhesion of repair composite. Conclusion: Among different lasers, Er;Cr:YSGG laser can be chosen as a suitable technique for surface treatment of unsatisfactory composites

Profilometeric and SEM evaluation of effect of polishing on surface roughness of two composites [silorane-based and methylmethacrylate-based] and a Glass ionomer

To evaluate the effect of polishing on surface roughness of silorane-based composite using profilometery and Scanning Election Microscopy [SEM] and compare it with that of a methylmethacrylate- based composite and a glass ionomer. In this study, 3 groups [n=28] were tested: specimens of two composites [Filtek P90 and Filtek P60] and a glass ionomer [Fuji IX] which were prepared in polyethylene molds [4 mm diameter x10 mm Height]. Half of the specimens in each group were finished with 180-grit silicon carbide paper and the remaining were finished with 180-grit, and subsequently polished with 250, 400, 800, 1000, 2000, and 2500-grit silicon carbide papers. The surface roughness was evaluated using a contact profilometer and then mean [R[a]] and maximum [R[max]] of surface roughness were recorded. Then, the surface of 4 specimens of each subgroup was observed under SEM. Statistical analysis was performed with T-test, ANOVA and Dunnett T3 tests. In all materials, Ra was different between polishing with 180 and 2500-grit silicon carbide papers. In 180-grit group, only Ra of Filtek P60 and Fuji IX showed significant difference [P=0.01]. In 2500-grit group, there was no significant difference between the Ra of Filtek P60 and Filtek P90 [P=0.56]. Polishing is recommended for the glass ionomer and posterior composite restorations