The purpose of this study was to evaluate the effect of various finishing and polishing procedures on the surface roughness of three new tooth-coloured restorative materials. The materials included a hybrid composite resin (Filtek Z250), a packable composite resin (Filtek P60), and an ormocer (organically modified ceramic) (Definite). Thirty-two specimens of each material were prepared and randomly divided into four finishing and polishing groups (n =8): (i) diamond bur/silicone polishers, (ii) diamond bur/Sof-Lex discs, (iii) carbide bur/silicone polishers, (iv) carbide bur/Sof-Lex discs. Average surface roughness (Ra) in micrometers was measured with a Mitutoyo Surftest-402 Surface Roughness Tester and the data compared using anova, at P less than or equal to0.05. Surface topography was also assessed using the scanning electron microscope (s.e.m) from samples of each group. The Mylar strip produced the smoothest surface and finishing/polishing procedures; (ii) and (iv) were significantly smoother than (i) and (iii). The lowest variability in initial surface roughness between materials was also observed with ormocer group.
The aim of this in vitro study was to evaluate the shear bond strength (SBS) of Silorane System Adhesive to enamel and dentin surfaces that had been etched with different procedures. Ninety freshly extracted human third molars were used for the study. After the teeth were embedded with buccal surfaces facing up, they were randomly divided into two groups. In group I, specimens were polished with a 600-grit silicon carbide (SiC) paper to obtain flat exposed enamel. In group II, the overlying enamel layer was removed and exposed dentin surfaces were polished with a 600-grit SiC paper. Then, the teeth in each group were randomly divided into three subgroups according to etching procedures: etched with erbium, chromium:yttrium-scandium-gallium-garnet laser (a), etched with 35% phosphoric acid (b), and non-etched (c, control). Silorane System Adhesive was used to bond silorane restorative to both enamel and dentin. After 24-h storage in distilled water at room temperature, a SBS test was performed using a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed using two-way ANOVA and Bonferroni tests (p < 0.05). The highest SBS was found after additional phosphoric acid treatment in dentin groups (p < 0.05). There were no statistically significant differences between the laser-etched and non-etched groups in enamel and dentin (p > 0.05). The SBS of self-etch adhesive to dentin was not statistically different from enamel (p > 0.05). Phosphoric acid treatment seems the most promising surface treatment for increasing the enamel and dentin bond strength of Silorane System Adhesive.