A review of the requirements and hazards of toxic metals from orthodontic wires

Background: Orthodontics is a part of dentistry that includes preventive methods and correction of dental irregularities that need to be repositioned by functional and mechanical tools to provide an ideal occlusion and a beautiful face for patients. There are currently four metal arch wires used in orthodontic treatment: stainless steel alloy, cobalt-chromium alloy, nickel-titanium alloy, and beta-titanium alloy. Toxic effects generally occur when the bodychr('39')s tissues are exposed to sufficient amounts of metal ions for long periods of time. Objectives: The present study briefly reviews the requirements and hazards of toxic metals from orthodontic wires. Methods: The present review study was carried out during the review of the available reliable sources and reference documents and scientific-research articles published in international journals and databases with the focus on the requirements and hazards of toxic metals from orthodontic wires. Results: Optimal characteristics of an arch wire for optimal performance are: spring return, ductility, modulus of elasticity, biocompatibility and low friction. Therefore, the release of metal ions from dental alloys is worrying due to local and systematic chemical, mutagenic, immunogenic and toxic effects. Conclusion: Today, most orthodontic brackets, braces, and arch wires are made of stainless steel and nickel titanium, all of which contain varying amounts of nickel, chromium, and cobalt ions. Increasing the amount of ions released from orthodontic alloys causes a cytotoxic state for the body. Although orthodontic alloys contain anti-corrosion agents, they have been shown to be prone to corrosion in dynamic oral environments.