Nanoparticles are used in various fields such as dentistry. Although there are concerns about their unknown effects on the environment and human health. Due to the increasing use of nanoparticles in various fields of dentistry, the purpose of this study was to review the application of nanoparticles in orthodontics. The present study is a review study and was conducted using the keywords Nano Chitosan, Nano ZnO, Nano silver, Nano crucumin, Nanoparticles, and Orthodontics. The desired keywords were searched in Google Scholar, Scopus, PubMed, and Web of Science databases, and the relevant articles were selected. According to the studies, all silver nanoparticles, titanium oxide, curcumin, zinc oxide, chitosan, and tetravalent ammonium derivatives show good antibacterial properties. To investigate the effect of each of these nanoparticles on bond strength, more studies are recommended. Regarding the addition of ACP nanoparticles, calcium-phosphate nanoparticles, and fluoride to reduce caries, the current evidence is insufficient, so new studies are recommended for further investigation. Studies show that adding zinc oxide nanoparticles to orthodontic wires reduces the friction between the wire and the bracket while adding titanium oxide nanoparticles to the bracket increases the friction. Although the evidence in the field of toxicity of nanoparticles is insufficient, it seems that nanoparticles are at least not more toxic than conventional substances.
