Influence of Different Polishing Methods on Surface Roughness and Microhardness of Dental Composites

Abstract

The surface roughness and microhardness of dental composites greatly affects the durability of restorations. To evaluate the effect of three different polishing systems (Sof-Lex, Enhance+PoGo, Kenda) on the surface roughness and microhardness of microhybrid (Herculite XRV, Filtek Z250 and Charisma Flow) and nanohybrid (Herculite XRV Ultra, Filtek Z550 and Charisma Bulk Flow) composites resin used for dental fillings. Six different composites were used in the study. From each material, 40 cylinder-shaped samples were made. All samples were polymerized and polished using three different methods. To evaluate surface roughness a confocal laser microscope was used, and microhardness was determined using a universal Vickers hardness tester.The data were analysed using the one-way ANOVA test at a significance level of 0.05 for both tests. The smoothest surfaces in all groups of composites were obtained for control samples. Also in all groups of composite samples no statistically significant differences were found between the Sof-Lex and Enhance+PoGo. The measurement of surface roughness obtained for the Kenda system showed significantly lower values than for the other two methods. The surfaces of the control samples showed statistically significantly lower microhardness values compared to all polishing systems for all six tested resin composites, additionally no statistically significant differences were found between all finishing and polishing methods. Regardless of the finishing and polishing method used, the lowest microhardness values among microhybrid materials were found for Charisma Flow, while among nanohybrid materials the lowest values were obtained for Herculite HRV Ultra. Finishing and polishing increases the microhardness of microhybrid and nanohybrid composite resin. The use of Kenda three step polishing system resulted in smoother surface for all tested composite materials compared to the Sof-Lex and Enhance+PoGo systems, while the finishing and polishing method had little effect on the microhardness of the surface.

Keywords

• microhardness
• roughness
• resin composites
• dental fillings
• polishing procedures