Authors: E.L. Kostoryz, C.J. Utter, Y. Wang, V. Dusevich and P. Spencer
Affilation: University of Missouri-Kansas City, United States
Pages: 647 - 650
Keywords: silica, silicon dioxide, OX50, aerosil 200, nanocomposite
Safety assessment of dental composites is focused on the toxicity of leachable unreacted monomers. With the advent of nanostructured materials, safety assessment needs to include the potential toxicity of nanoparticles. The objective of this study was to evaluate the cytotoxicity of a dental nanocomposite dust, silica fillers and Bis-GMA. Nanocomposite dust contained clusters of particles with average diameter of 29.9 ± 2.9 nm. Elemental analysis indicated particle composition as silica (Si). There was affinity of nanocomposite particles to attach the cell membrane that may have facilitated cellular uptake of silica particles. This in turn, may have caused the mild cytotoxic to L929 cells after 72 hr exposure at 37oC/5%CO2. Under similar conditions of exposure, the silica Aerosil 200 was non-cytotoxic while the silica OX50 was cytotoxic with an IC50 value of 58 g/ml. Addition of a toxic dose of OX50 (75g/ml), changed the dose-response of bis-GMA (IC50 15M) and become deadly to the cells. Our findings indicate that nanocomposite particles are taken up into cells and reside in the cytoplasm exhibiting some toxicity to the cell monolayer. This toxicity could be due to the effects of the nanoparticle, unreacted mechacrylate or both as leachable components of the nanocomposite.
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