Development of Titanium Surfaces Oxidized by Electrolytic Plasma, for Biomedical Application

Local drug delivery systems used in dental implants need to have uniform pore size distribution, adequate wettability, chemical composition, and biocompatibility. In the present work, titanium was treated by pulsed plasma electrolytic oxidation (PPEO), using 0.025 M sodium dihydrogen phosphate and 0.25 M calcium acetate as electrolytes, aiming at use in drug delivery systems. Pulse with Ton/Toff (width pulse/repetition time) of 50 μs/100 μs or 100 μs/50 μs, duty cycle 0,33, and 0.67, respectively, were used. After treatment, Ca/P ratio, wettability, crystalline phase, pore size and distribution were determined. The average pore size ranged from 1.5 μm to 2.3 μm according to the increase of energy supplied to the system. Pore distributions with lower dispersion were verified for the Ton/Toff condition of 50 μs /100 μs, using a current density of 30 mA/dm². On the other hand, the 100 μs/50 μs conditions produce larger pores, but with greater dispersion. In general, conditions with lower currents (30 mA/dm² and 38 mA/dm²) and Ton/Toff ratio = 50/100 were the most appropriate for use in drug delivery systems, due to their size and distribution of uniform pores, greater hydrophilicity, and Ca/P ratio close to desirable (1.67) was obtained.

Keywords:
PEO; pulsed plasma; titanium; coatings; oxide