Functional characterization of orthodontic bands coated with chitosan-zinc oxide nanocomposite: antibacterial and electrochemical characterization

After orthodontic treatment, dental caries develops in many patients, especially in posterior teeth beneath or around the molar bands. The objective of this study was to deposit a Nanocomposite coating composed of chitosan and zinc oxide nanoparticles (ZnO NPs) on orthodontic bands via electrophoretic deposition (EPD) and to characterize the Nanocomposite coating using various characterization techniques. ZnO NPs were synthesized in the laboratory and were incorporated in the chitosan based Nanocomposite coating deposited on commercially available orthodontic band. A Taguchi design of experiment (DoE) approach was used to optimize the EPD parameters, and it was concluded that an applied potential of 15 V with a deposition time of 5 min was the optimum parameter for uniform Nanocomposite coating on an orthodontic band. SEM image of Nanocomposite coating with a thickness of 5.11 μm exhibited uniform morphology. ZnO NPs were uniformly distributed over the chitosan matrix of the Nanocomposite coating. The hydrophilic nature of Nanocomposite coating showed a potential antibacterial effect against Streptococcus mutans at all-time points (p ≤ 0.05) which was confirmed by turbidity test. The highest antibacterial activity coincided with zinc ion release on day six. Potentiodynamic polarization showed a shift in corrosion potential from (-0.6966 V) to (-0.5949) towards the noble direction also by reducing the corrosion current density from (7.81 µA/cm2) to (4.04 µA/cm2) after depositing the Nanocomposite coating on orthodontic band indicating the improved corrosion resistance ability. This study concludes that Zinc oxide chitosan Nanocomposite coating on orthodontic molar bands can be done using Electrophoretic Deposition. This Nanocomposite coating has the potential to impart antibacterial activity to the orthodontic bands. These coated orthodontic bands possess antibacterial properties against Streptococcus mutans and are corrosion-resistant as proven by the electrochemical analysis.