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

[Effects of leached components from a hybrid resin composite on the reproductive system of male mice]

In the present animal study, twenty adult Syrian male mice were divided into two groups of 10 mice each. In the test group, components which leached from samples made from Filtek Z250 resin composite into 75% ethanol were daily administered to the mice for 28 days. In the control group, the procedure was repeated in the same way as the test group but without placing composite samples in the solution. Then, the body weight, weights of paired testes, Gonado Somatic Index, sperm viability, sperm motility, epididymal sperm reserve and daily sperm production were recorded. Four male mice in each group were mated with untreated female mice for 10 days. After that, the number of pregnant females and number of infants were recorded. The data were analyzed using repeated measures ANOVA, Chi-square test and t-test. There was a significant reduction in the sperm viability and sperm motility of male mice in the test group compared to the control group [P=0.001]. There was no any significant differences in other parameters between two groups [P>0.05]. This study showed that the leached components from resin composites cannot cause infertility but they could potentially cause some adverse effects on the reproductive system of male mice.