Effects of three different mouthwashes on the surface characteristics of nickel-titanium and Stainless steel archwires in orthodontics

Patients are recommended regular using of mouthwashes to control dental caries or periodontal diseases since orthodontic treatment may have detrimental effects on the tooth structures. However, chemical agents may potentially damage metal components of orthodontic appliances. The aim of this study was to evaluate the influence of three mouthwashes on the surface characteristics of nickel–titanium (NiTi) and Stainless steel (SS) arch wires.
Methods and Materials: 15 pieces of 0.016 inch NiTi and 15 pieces of 0.016-inch SS wires were randomly assigned into 5 groups including 2 controls (as- received and artificial saliva) and 3 experimental groups. The samples in all groups were stored in artificial saliva in an incubator at 37˚C for one month, after that, the test groups were immersed in Chlorhexidine 0.12%, Hydrogen peroxide 0.12% and Persica mouth washes for 30 min, 1.5 h and 1.5 h, respectively. Then, the samples were washed by distilled water and returned to artificial saliva for more than two months. Surface topography changes and the number of corrosion holes were characterized via a scanning electron microscope (SEM).Two way ANOVA and Tukey tests were used to compare groups.
SEM photographs of the present study showed significant corrosion rate among "as- received" group and Persica (p=0.04), Chlorhexidine (p=0.02), and artificial saliva group (p=0.008) in NiTi wires, but there was no significant difference in the surface topography between any of the groups in SS wires.
Alterations in surface of NiTi wires were significantly more than SS wires. Although not significant, 0.12% Chlorhexidine and Peroxide showed higher pitting view on SS and NiTi wires, respectively compared to other mouthwashes