Water sorption, solubility, degree of conversion, and surface hardness and topography of flowable composite utilizing nano silica from rice husk

Abstract

This study aimed to evaluate water sorption (WS), solubility (SO), surface topography, degree of conversion (DC) and Vickers hardness (VH) of experimental flowable composites (EFCs) made from nanohybrid silica extracted from rice husk in comparison with Revolution Formula 2™ (RF2). Samples of EFCs (EFC50B and EFC40B) and RF2 were prepared in different molds depending on the test type (n = 5). Data was analyzed using non-parametric Kruskal–Wallis and Mann–Whitney tests at p = 0.05. In Mann–Whitney test, the values of EFC50B and EFC40B in WS test were increased after immersion when compared to RF2 (p < 0.05) whilst, the SO values of EFC40B were higher when compared to the other groups (p < 0.05). The 40 s light-curing resulted in the most suitable DC and VH values of EFC40B while the 80 s light curing was more optimal for EFC50B when compared to other exposure time (p < 0.05). SEM pictures showed different surface characteristics between experimental and commercial products before and after immersion. In conclusion, the EFCs have promising results to be a potential product derived from agricultural bio-waste.

Keywords

• Flowable
• Resin composites
• Rice husk
• Water sorption
• Solubility
• Nanohybrid silica