Evaluation of corrosion resistance of free-machining titanium alloy

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Current dental CAD/CAM process demands the development of titanium alloy which exhibits excellent machinability and corrosion resistance. Recently, free-machining titanium alloy produced by dispersion of a sulfide or rare earth elements. This study evaluated the corrosion resistance and cytotoxicity of free-machining titanium alloy for dental application through the electrochemical properties and. cell proliferation test.Pure titanium, Ti-3Al-2V alloy and two free-machining titanium alloys (DT2F, DAT52F : Daido steel) were used in this experiment. Polarization resistance and the potentiodynamic polarization profile were measured using an electrochemical device (PARC Potentiostat, Model 273 with soft-ware M352C) and a corrosion cell stored in a thermostatic chamber at 35℃. A 0.9% NaCl and a 1.0% lactic acid solution deaerated with pure nitrogen gas were used as a test solution. SEM observation examined presence of pitting corrosion following the electroche mical measurement.Using L929 m … More urine fibroblast, 5,000 cells/ml of Eagle's MEM+10% FBS were seeded on the metal (13mm diameter×1mm thick) in 24 well (16mm diameter) and incubated at 37℃ in 5% CO2. After 3 and 7days, the number of cells was counted using cell counterThe natural electrode potential and the polarization resistance of free-machining titanium alloys were lower than those of titanium and Ti-3Al-2V alloy. From the potentiodynamic polarization behavior, all titanium alloys showed same passive potential (around 0.0 V vs SCE), However free-machining titanium alloys showed remarkable high passive current density. The transpassive potential was nearly the same for all alloys. The pits were recognized on the surface of free-machining titanium alloy which was tested in the 0.9%NaCl solution. Accordingly, it was estimated that the corrosion resistance of free-machining titanium alloy was inferior to pure titanium and Ti-3Al-2V alloy.The proliferated cell number was not significantly different at 3 days, while the cell proliferation rate of free-machining titanium alloys was lower than that of pure Ti at 7 days (P<0.05). Less