Influence of fluoridated mouthwashes on corrosion resistance of orthodontics wires

The aim of the present study was to classify the different alloys commonly used to make orthodontic wire according to their corrosion resistance in different media. The four materials analysed were titanium-based alloys: TMA, TiNb, NiTi and CuNiTi, which were tested in three fluoride mouthwashes: Elmex®, Meridol® and Acorea® as well as in Fusayama Meyer artificial saliva. The electrochemical study showed that the alloys could be divided into two groups. In one group were the NiTi-based alloys which were subject to strong corrosion in the presence of monofluorophosphate found in Acorea® solution. In the other group were TiNb, which was the most resistant to corrosion, and TMA, which corroded strongly with the stannous fluoride found in Meridol® mouthwash. The results obtained in the present study will enable us to provide attending practitioners with advice concerning fluoride mouthwash to recommend, depending on the treatment phase and the alloy used. So we can advise Elmex® mouthwash for patients with TMA and NiTi-based orthodontics wires but we suggest Acorea® or Meridol® mouthwashes for patients with TiNb orthodontics wires.