COMPARISION OF MEAN SURFACE ROUGNESS OF NANOHYBRID AND MICROHYBRID COMPOSITE RESINS USING ONE STEP POLISHING SYSTEM (AN IN VITRO STUDY)
The objective of this comparative study (in vitro) was to compare mean surface roughness (Ra) of Nanohybrid and Microhybrid composite resins using one step polishing system. A total of 120 composite resin samples were prepared with 60 samples of Nanohybrid composite in Group A and 60 samples of Microhybrid composite in Group B. The specimens were mounted on acrylic blocks while comparing their mean surface roughness (Ra in microns) using one step polishing system (optrapol) after light cure polymerization. The Ra reading was taken with portable surface roughness tester (PSRT). As per descriptive statistics, mean Ra and SDs for nanohybrid composite resin in Group A was recorded as 0.087+0.036 whereas mean Ra and SDs for microhybrid resin in Group B was recorded as 0.112+ 0.047. The comparison between mean Ra of both composites using student t test showed p value as 0.0014, which is considered as significant. Significant difference exists between surface roughness of nanohybrid and microhybrid composite resins after polishing using one-step technique which means polishability of the former is higher than the latter. Nanohybrid composite therefore has superior surface & optical characteristics and can be used frequently with enhanced results than microhybrid composite. However, further studies are required to compare their surface roughness using a different polishing system, and to determine the effects of the polishing technique on mechanical properties & surface characteristics of composite resins.