Effect of Aging on the Surface Roughness of Nanocomposite Restoratives

Objectives:The aim of this in vitro study was to evaluate the surface roughness of nanohybrid and nanoceramic filling materials after an aquaeous aging for one year.Methods:120 disk-shaped specimens were fabricated by using two nanohybrid (Grandio-Voco),(Tetric EvoCeram-Ivoclar Vivadent) and one nanoceramic (CeramX mono-Dentsply, De Trey) restoratives. Each material group was assigned to one of the three polishing subgroups (Astrobrush system, Ivoclar Vivadent ; Occlubrush system, KerrHave ; Sof-Lex disks ,3M ESPE ) and to a control group (Mylar matrix strips, Yates-Bird). After the polishing procedures, baseline Ra values of the specimens were determined using a profilometer (Perthen Perthometer M4P).All specimens were then stored in bi-distilled water for one year. After this aging procedure, new surface roughness values were determined and data were statistically analyzed using one way ANOVA and Tukey's Multiple Comparison tests. Results:Regarding the Tetric EvoCeram and CeramX mono materials, no statistically significant differences were found between the baseline and aged subgroups of all of the polishing techniques (p>0,05). Ra results of both of the baseline and aged test groups of Grandio material showed however that all the three polishing systems produced significantly rougher surfaces when compared to the related control groups(p<0,001).There were no significant differences between the values of the baseline and aged Grandio surfaces when Sof-Lex polishing system were used (p>0,05).But, aged surfaces of this material which had been polished with Astrobrush or Occlubrush techniques demonstrated significantly higher Ra values than the baseline results (p<0,001).Conclusion:Aqueous aging of nanocomposites shows material-dependent effects on the surface texture of the restoratives. All the polishing techniques tested in this study can be successfully used for the Tetric EvoCeram and CeramX mono materials. But only Sof-Lex contouring and finishing disks seem to be a proper method in order to polish the restorations of Grandio materials.