Investigation of corrosion behaviors of orthodontic wires in various solutions

Orthodontics is a discipline that takes up the normal structure and growth, anomalies and their treatment of tooth, jaw bone and face complex. Wires, springs and brackets used in orthodontic treatment must be produced from materials that appropriate with oral cavity and used without suffering corrosion and losing mechanical properties. In this study, wires chosen from the materials mostly aforementioned in scientific literature and used by orthodontists which are 18-8 Cr-Ni stainless steel, nickel-titanium, beta-titanium and cobalt-chromium-nickel alloys are kept in three artificial saliva solution which are modified Fusuyama, modified Fusuyama with 1g/L NaF addition and modified Fusuyama with 1.7% H3PO4 addition in a situation that is equal to oral cavity temperature and corrosion behaviors observed by using weight loss method and looking through macro surface photographs. At last, changes in the value of surface hardness are investigated by taking surface mikro hardness measurements. Consequently it is determined that corrosion rate of all wires kept in the modified Fusuyama solutions with NaF and H3PO4 addition are higher and the most affected wires are nickel titanium and beta titanium alloy wires. Keywords: Orthodontic wire, corrosion, artificial saliva