Corrosion and Micromorphological Analysis of Temporary Stainless Steel and Titanium Alloy Anchorage Devices

Abstract

The aim of this study was to compare the surface micromorphology and corrosion resistance of different temporary anchorage devices (TADs) composed of titanium alloy (SIN®) and stainless steel (DAT Steel® and Bio Ray®). Ten samples of each TAD were submitted to qualitative analyses using energy-dispersive and scanning electronic microscopy before and after immersion in artificial saliva (1500 ppm of fluoride) for 30 days. The chemical analysis was done by X-ray fluorescence, and the corrosion tests were performed by electrochemical means (open circuit potential—OCP, potentiostat, and electrochemical impedance spectroscopy—EIS, using anodic potentiodynamic polarization curves). Passive film resistance (PFR) and corrosion current were established. The corrosion rate was determined by the mass loss test. Greater smoothness and fewer machining defects were observed for the stainless steel TAD before artificial saliva immersion. Comparatively, higher corrosion resistance was found for titanium alloy TAD after immersion in saliva. There was no release of ions into the TAD when immersed in artificial saliva. ANOVA and Tukey tests showed that OCP (V) was significantly lower for the titanium alloy TAD (p = 0.030) than the stainless steel brands. Epite (V) and Epite−OCP (V) were significantly higher for the titanium alloy TAD (p = 0.0009 and p = 0.0005, respectively). Stainless steel TADs presented lower roughness surface than titanium alloy TAD, although the latter presented higher corrosion resistance than the former.