Effect of Nanofiller Technology on Surface Properties of Nanofilled and Nanohybrid Composites

Context: Nanocomposites are becoming popular today because of the manufacturers claiming high surface smoothness and good abrasion resistance properties thus improving the longevity of the restoration. Aims: This in vitro study was carried out to investigate the effect of nanofillers on surface roughness and abrasion resistance of nanofilled composite- Filtek Z350 (3M ESPE) and nanohybrid composite- Tetric N Ceram (Ivoclar Vivadent) after polishing and abrasion. Methods and material: A total of fifteen disc specimens of each category of material were prepared under standardized conditions. The discs were finished and polished according to manufacturer's instructions. The samples were examined for surface roughness using Mahr Perthometer M2 followed by scanning electron microscope examination. In order to assess the performance of the materials in simulated oral conditions the samples were then subjected to toothbrush-dentifrice abrasion and the resultant surface roughness was compared for both the materials. Statistical analysis: Mean value of surface roughness was calculated for both the groups from Ra values before and after toothbrush-dentifrice abrasion followed by calculation of Standard deviation (SD). Paired-t test was then applied to compare the surface roughness values before and after toothbrush-dentifrice abrasion within the same group. Results: Initially the surface roughness of Filtek Z350 were found to be superior to Tetric N Ceram but after subjecting to toothbrush dentifrice abrasion Tetric N Ceram showed greater increase in surface roughness as compared to Filtek Z350. The difference was found to be statistically significant. Conclusions: Nanofiller type, size and distribution significantly influence the surface properties of composites. Though nanohybrid composite showed a better initial surface polish but nanofilled composite showed a better abrasion resistance.