Study of Al–SiO 2 Aesthetic Composite Coating on Orthodontic Metal Archwire.

Nickel–titanium orthodontic wires (NTWs) play an essential role in orthodontic treatment. However, their corrosion and aesthetic properties limit their applications. To improve the aesthetic effects of nickel–titanium orthodontic archwires, we prepared aluminium–silicon dioxide (Al–SiO₂) as a biocompatible layer coated onto the NTWs. The Al–SiO₂ coating was first fabricated using physical vapor deposition magnetron sputtering, and its physicochemical and biocompatibility properties were investigated. Al–SiO₂ layers were well coated on the NTWs. The corrosion currents in the nickel–titanium (NiTi) control, Al–SiO₂-coated NiTi experimental, stainless steel (SS) control and Al–SiO₂-coated SS experimental groups were 23.72 μA cm⁻², 1.21 μA cm⁻², 0.22 μA cm⁻² and 0.06 μA cm⁻², respectively. Al–SiO₂-coated NTWs with reduced corrosion current density indicated that the preparation of Al–SiO₂ coating on the surface of NiTi and SS could reduce the tendency of electrochemical corrosion. The friction coefficients of orthodontic wires in the NiTi control, NiTi experimental, SS control, and SS experimental groups were 0.68, 0.46, 0.58 and 0.45, respectively. A low friction coefficient was observed in the Al–SiO₂-coated NTWs, and the reduced friction coefficient improved the efficiency of orthodontics. Furthermore, the excellent biocompatibility of the NTWs and SS coated with Al–SiO₂ indicates that Al–SiO₂ as a novel aesthetic layer could improve the physicochemical properties of NTW and SS without causing cytotoxicity, which has considerable potential for modification of NTW and SS surfaces. [ABSTRACT FROM AUTHOR]