EIS Study on Interfacial Properties of Passivated Nitinol Orthodontic Wire in Saliva Modified with Eludril® Mouthwash

Abstract

This work aimed at first-time use of EIS measurements to study the effect of ready-to-use Eludril® mouthwash containing 0.10% chlorhexidine digluconate as active component on corrosion performance of Nitinol orthodontic wire in artificial saliva at 37°C. In vitro corrosion resistance of the autoclaved Nitinol wire was studied under open circuit potential conditions using EIS combined with cyclic potentiodynamic polarization curves. HREM, SEM, EDS, and microhardness testing were used to study the properties of the Nitinol wire before and after corrosion measurements. EIS study of the interfacial properties of the Nitinol electrode | oxide layer | saliva solution system revealed the capacitive behavior of the material with high corrosion resistance. EIS allowed to determine resistance of charge transfer through the oxide | electrolyte interface. It was found that kinetics of pitting corrosion of the Nitinol electrode in saliva increases with the rising content of Eludril® mouthwash.