A Systematic Review on Nano Coated Orthodontic Brackets and its Antibacterial Effects

Introduction: Oral cavity is a natural habitat of bacteria which proliferates when an orthodontic appliance is placed which leads to enamel demineralisation or white spot lesions. In order to reduce the bacterial proliferation, the surface coating of brackets using nano particles came into existence. Aim: The aim of this systematic review is to assess the different surface modifications using nano coating materials and evaluate the antibacterial properties of these nano coated orthodontic brackets. Materials and Methods: A systematic review was conducted in September 2021, analysing the microbial adhesion and antibacterial properties of orthodontic brackets after application of nano-coating against uncoated brackets was conducted from the available electronic database during January 2000 to June 2021, which included PubMed, Embase, Google Scholar. Because of the less number of in-vivo studies, in-vitro studies were also included. An analysis on the microbial adhesion and antibacterial effects of various orthodontic brackets was done. The results were tabulated after performing risk of bias assessment for each study. Results: Based on the inclusion and exclusion criteria, 13 studies were included in the study. Risk of bias was medium for majority of the selected studies. As per the previous literature, bacterial adherence of Streptococcus mutans, Streptococcus sobrinus, Aggregatibacter actinomycetemcomitans, Lactobacillus acidophilus, Actinomyces viscous and Candida albicans was reported lower in groups of brackets coated with silver nano particles than that in the groups of brackets without the addition of silver nano particles. The corrosion level on the silver or silver platinum (Ag-Pt)-coated specimens was lower than that on the non coated specimens. Conclusion: The stainless-steel orthodontic brackets coated with various nano coating materials like silver, silver-platinum, titanium, Zinc Oxide (ZnO) and Copper Oxide (CuO) exhibited adequate antibacterial effect. This shows that in orthodontic patients, especially the one susceptible to caries, the amount of plaque accumulation is significantly reduced when nano-coated orthodontic brackets are used. They reduce the microbial colony count and prevent enamel demineralisation and white spot lesions. Further clinical trials must be carried out on a large scale to confirm the results.