Incorporating nano graphene oxide to poly-methyl methacrylate; antibacterial effect and thermal expansion.

Aim: This in vitro study was performed to evaluate antibacterial effect and thermal expansion of commercial available poly-methyl methacrylate (PMMA) incorporated by nano graphene oxide (GO) in different concentration. Method: Nano graphene oxide in five concentrations 0%, 0.05%, 0.1%, 0.15% and 1% by weight was incorporated to PMMA to form groups I-V respectively. To evaluate the antibacterial effect against Streptococcus Mutans, minimal inhibitory concentration (MIC) for GO dispersion was done and agar well diffusion test for groups I-IV was done. Thermal expansion was assessed through measuring the linear coefficient of thermal expansion. Results: For antibacterial effect, all concentrations tested for MIC showed inhibition zone varied from 0.5 to 2mm in diameter. All tested groups evaluated by agar well diffusion method showed no inhibition zones except for group II. Significant reduction in coefficient of thermal expansion was showed by increasing GO concentration. Conclusions: Incorporation of GO in to PMMA at concentration of 0.5% can inhibit the growth of Streptococcus Mutans. There is an inverse relation between the concentrations of GO and the coefficient of thermal expansion.