Caries Direction Antimicrobial Activity of Zinc Oxide Nanoparticles Containing Cement for the Management of Orthodontic Teeth against Streptococcus mutans and Lactobacillus casei

Abstract Streptococcus mutans and Lactobacillus casei are the two bacterial species that cause tooth decay and affect orthodontically treated teeth. In orthodontic treatment, zinc oxide (ZnO) is incorporated into the cement, providing antibacterial properties. The objective of the study was to evaluate the antimicrobial activity of zinc oxide nanoparticles containing cement for the management of orthodontic teeth. ZnO nanoparticles were prepared using ZnCl 2 and then incorporated into the Orthodontic Portland Cement (OPC) with a grade of 43. It was evaluated for physicochemical parameters like colour, odour, appearance, and pH. Flexural strength, split tensile strength, and setting time were also determined with standard ASTM C496 methods. The antibacterial activity of the ZnO nanoparticles was determined by crystal violet staining. It was found that biomass growth was lower in the cement containing zinc oxide nanoparticles than in the control samples. There was inhibition of biofilm formation in the presence of zinc oxide nanoparticles incorporated into the cement material, thereby enhancing the antimicrobial effect. The incorporation of ZnO nanoparticles into orthodontic cement demonstrates enhanced antimicrobial properties, making it beneficial for managing oral bacterial colonization during orthodontic treatment.