Evaluation of the efffect of different polishing techniques on staining of nanofil and microhybrid composites

This in vitro study aim to evaluate the effect of different polishing techniques (bur; bur+diamond polish; sof-lex; sof-lex+diamond polish; PoGo; PoGo+diamond polish), on staining (artificial saliva; tea) of nanofil (Clearfil Majesty Esthetic Ultimate) and microhybrid (Gaenial) composites. A total of 360 composite dics, 120 from each type of composite were prepared with 8mm diameter and 2mm thickness. Then composites were polymerized according to their manufacturer?s instructions (Optilux 501;Kerr). Following thesurface standardization of the composite specimens with tungsten carbide bur, each composite group was randomly divided into 3 groups (n=120). Specimens in each group was further divided into 2 subgroups (n=20) in which different polishing techniques were applied with the diamond polishing paste (bur+diamond polish; soflex +diamond polish; PoGo+diamond polish) or alone. In order to represent the effect of polishing techniques on staining, 10 specimens in each group was stored in artificial saliva whereas other 10 specimens were immersed in tea solution. Following storage in artificial saliva for 24 hours at 37°C, initial color measurements were performed using a spectrophotometer (Minolta CM-2600d). Specimens in tea groups were immersed in tea for 6 hours followed artificial saliva storage for 18 hours,whereas artificial saliva group was stored in artificial saliva for 24 hours at 37°C which was renewed after 24 hours during the whole study. Staining cycle was repeated for two weeks and at the end of first and second weeks, color differences (?E) were evaluated with the CIE Lab system. Results were statistically analyzed using paired t- test, one-way ANOVA ve post hoc Tukey tests at p<0.05.Tea solution significantly resulted in more color change than the artificial salivawith all of the composites and polishing techniques tested (p<0.05). In tea groups,Clearfil Majesty Esthetic showed less color change than Ultimate when samepolishing techniques were compared (p<0.05). Differences between bur and sof-lexgroups in Ultimate and G-aenial composites were not significant (p>0.05). The onlysignificant difference in color change using tea solution between Clearfil MajestyEsthetic and G-aenial was determined in bur group (p<0.05). Except G-aenial PoGo group, combination of the polishing techniques with diamond paste significantlyreduced the color change in tea solution (p<0.05).