Mostafa Goodini, Sabah Etemadi, Reza Hatam, Atefeh Khavid, Atena b, Mohsen Safaei
The emergence of microbial resistance in bacterial pathogens to common antimicrobial agents is a significant challenge in their use. The purpose of this research is to investigate the antibacterial properties of a nanocomposite consisting of calcium hydroxide and manganese oxide against the oral pathogen Enterococcus fecalis. To determine the antibacterial effect of nanocomposites on E. faecalis, a total of 9 experiments were designed using the Taguchi method. In the experimental investigations, three factors of calcium hydroxide, manganese oxide nanoparticles, and their stirring time were investigated. These agents had three different levels and finally led to the identification of the optimal ratio that showed the greatest antibacterial effect. The nanocomposites made using test conditions 6 (calcium hydroxide 150 mg/mL, manganese oxide 9 mg/mL, and stirring time 60 minutes) showed the greatest effect in growth inhibition (0.29 CFU/mL). The properties of the synthesized nanocomposite as well as its components were evaluated through material characterization techniques. The structural properties and chemical composition of this nanocomposite were found to be favorable based on its characteristics. As a result, the nanocomposite consisting of calcium hydroxide and manganese oxide has beneficial antibacterial properties that make it suitable for increasing performance in various dental fields.
Prof. Vijay Kumar Thakur, Biorefining & Advanced Materials Research Centre, SRUC, Edinburgh, UK. 
