The influence of one-step polishing systems on the surface roughness and microhardness of nanocomposites

WOS: 000252557800009PubMed ID: 18335732Objectives: This in vitro study evaluated the surface roughness and microhardness of nanocomposites that contain nanoparticles and a microhybrid composite finished and polished with two different one-step polishing systems and a conventional multi-step polishing system. Methods and Materials: The materials evaluated were Filtek Supreme XT, Grandio, Ceram Y, Aelite Aesthetic Enamel, Tetric EvoCeram and Filtek Z250. A total of 240 specimens (10-mm in diameter, 2 mm. thick) were fabricated for both tests (n=120 each test) in a plexiglass mold covered with a Mylar strip. After polymerization, five specimens per group received no polishing treatment and served as the control for both tests. For each composite group (n=15), the specimens were randomly divided into three polishing systems: PoGo, OptraPol and Sof-Lex. All polishing systems were applied according to the manufacturers' instructions after being ground wet with 1200 grid silicon carbide paper. The surface roughness values were determined using a profilometer. The microhardness measurements were performed using a digital microhardness tester (load 500 g; dwell time 15 seconds). The data were analyzed using the one-way ANOVA test at a significance level of 0.05 for both tests. Multiple comparison was performed with the Duncan Multiple Range test. Results: The smoothest surfaces were achieved under Mylar strips in all composite groups (p0.05). In the Tetric EvoCeram group, Sof-Lex exhibited the highest roughness values. No statistically significant differences were evaluated between polishing systems (p>0.05); whereas, the surfaces under Mylar Strip showed statistically significant lower values than the polished surfaces in terms of microhardness (p<0.05). Conclusion: One-step polishing systems may be successfully used for polishing nanocomposites