Evaluation of Corrosion of Rhodium Coated and Uncoated Nickel Titanium Archwires after Immersion in Different Mouthwashes
Author(s): Heba Abdul Jabbar Nema*, Shaymaa Shaker Taha
Introduction: Nickel titanium orthodontic archwires are widely used due to their favourable characteristics mainly in
levelling and alignment stage. Gingivitis and enamel demineralization are commonly encountered side effects of fixed
orthodontic treatment. Mouthwashes are prescribed as adjunct aids for good oral hygiene but their prolonged use may
result in corrosion of orthodontic appliances.
Aim: The current study was designed to evaluate corrosion of Rhodium coated and conventional nickel titanium orthodontic
archwires in different commercially available mouth washes.
Materials and methods: Samples of rhodium coated and un-coated nickel titanium wire were immersed in four media
(Listerine cool mint, Listerine total care zero, silca and distilled water as a control group) for two months. The atomic force
microscopy AFM was used for evaluation of wires. Analysis of variance test (ANOVA) and independent t-test was used to
compare the means and Turkey’s (HSD) test used when there was significant difference.
Results: Significant differences were found among different immersion media for both types of archwires and the highest
Ra values were recorded after immersion in Listerine cool mint then in total care zero. Independent t-test revealed
significant differences between tested archwires in Listerine cool mint and total care zero. No significant difference was
found in as received, distilled water and silca.
Conclusion: Acidic media increase corrosion tendency in comparison to neutral one as the Ra values increased with
decreasing pH. Rhodium coated have higher corrosion tendency compared to conventional in acidic mouthwashes and
should be used with caution with them.