Surface analysis and corrosion resistance of different stainless steel orthodontic brackets in artificial saliva.

摘要

The purpose of this study was to investigate the variation in corrosion resistance of commercial stainless steel (SS) brackets with different brands and types for the same application, using the electrochemical technique. The linear polarization test was used to evaluate the corrosion resistance, in terms of polarization resistance (R(p)), of as-received commercial SS brackets in acidic artificial saliva. A two-way analysis of variance was used to analyze the R(p) with the factors of brand and type. A scanning electron microscope and an atomic force microscope were used to analyze the surface morphology and roughness, respectively. The X-ray photoelectron spectroscopy was used to identify the chemical composition of the passive film on SS brackets. Results showed that different brands of SS brackets had a statistically significant difference in R(p) (P < .0001), whereas there was no statistical difference between the bracket types ("Roth" and standard) (P = .27). Different surface topography, includingsurface roughness and defect, was present among the tested SS brackets. The same passive film structure, containing Cr(2)O(3)/Fe(2)O(3) with small amounts of NiO, was observed on all SS brackets. The surface topography of the commercial SS brackets with identical surface passive film structure did not correspond with the difference in corrosion resistance.