The effect of one-step and multi-step polishing systems on the surface roughness and microhardness of novel resin composites

Abstract

Objectives:The objective of this in vitro study was to evaluate the surface roughness and micro-hardness of three novel resin composites containing nanoparticles after polishing with one-step and conventional multi-step polishing systems.Methods:A total of 126 specimens (10 X 2 mm) were prepared in a metal mold using three nano-composites (Filtek Supreme XT, Ceram-X, and Grandio), 21 specimens of each resin composite for both tests (n=63 for each test). Following light curing, seven specimens from each group received no polishing treatment and served as controls for both tests. The specimens were randomly polished using PoGo and Sof-Lex systems for 30 seconds after being wet-ground with 1200-grit silicon carbide paper. The mean surface roughness of each polished specimen was determined with a profilometer. The microhardness was determined using a Vickers hardness measuring instrument with a 200-g load and 15 seconds dwell time. The data were analyzed using the Kruskal-Wallis test and the post hoc Dunn's multiple comparison tests at a significance level of .05.Results:Among all materials, the smoothest surfaces were obtained under a matrix strip (control) (P<.05). There were no statistically significant differences among polishing systems in the resin composites for surface roughness (P>.05). The lowest hardness values for the three resin composites were obtained with a matrix strip, and there was a statistically significant difference compared with other polishing systems (P<.05) whereas no statistically significant differences were observed between the polishing systems (P>.05).Conclusion:The current one-step polishing system appears to be as effective as multi-step systems and may be preferable for polishing resin composite restorations.

Effect of two different polishing systems on fluoride release, surface roughness and bacterial adhesion of newly developed restorative materials

“…Finishing and polishing procedures are the most important steps for the successful clinical performance of restorative materials . There is a wide variety of finishing and polishing instruments available for dental professionals and their effect on the surface roughness and microhardness of various restorative materials have been investigated in previous studies . Clinically, functional adjustments are necessary for most restorations and contouring and finishing procedures are essential to establish a good occlusal relationship .…”

“…There are many methods used to investigate the surface roughness of materials such as profilometers, scanning electron microscopy (SEM) analysis and atomic force microscopy (AFM). However, in many in vitro studies, the surface roughness of the materials was evaluated by using profilometer . Likewise, in the current study, profilometer was used to determine the Ra values.…”

“…In vitro studies demonstrated that the smoothest surface was obtained under a Mylar strip . However, under the clinical conditions, despite the careful placement of the Mylar strip, removal of excess material or contouring of restorations is usually required.…”

“…In another study, it was found that the surface of materials created with Sof‐Lex and PoGo polishing systems exhibited higher surface roughness than those produced with Mylar strips. However, there were no statistically significant differences between the surfaces created with both polishing systems . Similar to these results, in the present study, significant differences were not observed between the surfaces created with Sof‐Lex and Enhance/PoGo polishing systems in all study groups except for Amalgomer CR ( P > .05).…”

“…The most important reason resulting in the failure of restorations is secondary caries . With regard to this aspect, plaque formation on the surface of dental restoratives may cause an environment favorable for secondary caries, discoloration and/or periodontal disease occurence . An increase in surface roughness may facilitate bacterial adhesion due to the increase in contact area between the material surface and bacterial cells .…”