Investigation of nano-SiO2 impact on mechanical and biocompatibility properties of cyanoacryalate based nanocomposites for dental application

Although cyanoacrylate glues are widely used in medicine, cyanoacrylate-based nanocomposites have been recently suggested for dental restorative/filling applications. In the present research, SiO2 nanoparticles were used as filler for development of a novel dental nanocomposite base on alkoxy-ethyl-cyanoacrylate. The mechanical properties of nanocomposite samples filled with different levels of nano-sized SiO2 (wt%) were evaluated and comparisons were made with the neat cyanoacrylate. The hardness and wear behavior of the samples were measured using Vickers hardness and pin-on-disk tester, respectively. The wear mechanism of the samples was also evaluated using scanning electron microscopy (SEM). Furthermore, cell biocompatibility of the samples using MTT and LDH assays as well as inflammatory cytokine expression interleukin-6 (IL-6) from L929 cells was investigated. The results showed that an increase in nano-sized SiO2 content improves hardness and wear resistance of the cyanoacrylate-based nanocomposites and changes the wear mechanism from adhesive to abrasive. The results of cytotoxicity analysis showed a significant reduction in cell viability and IL-6 produced from the samples-exposed L929 cells compared with untreated control cells. Moreover, increasing the nano SiO2 powder content caused a decrease in the released formaldehyde.