ABSTRACT
Objective@#To explore the osteogenic activity of Zn/Ca/P-containing coatings on titanium implant surface modified by plasma electrolytic oxidation (PEO).@*Methods@#Three groups implants including Zn/Ca/P-containing surface treated by PEO in experimental groups and Ca/P-containing and TiO2 sandblasted surface in control group were randomly inserted in the bilateral mandibular of rabbits. Mechanical testing and implant-bone interface observation were performed at 4, 6, 8, 10 and 12 weeks after implantion.@*Results@#Zn/Ca/P-containing coating presented a microporous structure. The push-out value indicated the statistical differences among the three groups at each observed time point (P<0.05), and implant-bone bonding power reached a maximum value at 12 weeks, those in the Zn/Ca/P-containing group [(1.57±0.26) MPa] was higher than those in the group with sandblasted surface [(0.83±0.24) MPa] (P<0.05). Histological examination and implant-bone interface observation using field scaning electron microscope (FSEM) showed that the new bone of implant-bone interface increased with healing time and the result from Zn/Ca/P-containing group was superior to that from the control groups at each observed time point.@*Conclusions@#Zn/Ca/P-containing coatings by PEO can accelerate bone formation and remodeling, and enhance bone-implant bonding force.
ABSTRACT
PURPOSE: The purpose of this study was to investigate the corrosion behaviors of dental implant alloy after micro-sized surface modification in electrolytes containing Mn ion. MATERIALS AND METHODS: Mn-TiO₂ coatings were prepared on the Ti-6Al-4V alloy for dental implants using a plasma electrolytic oxidation (PEO) method carried out in electrolytes containing different concentrations of Mn, namely, 0%, 5%, and 20%. Potentiodynamic method was employed to examine the corrosion behaviors, and the alternating-current (AC) impedance behaviors were examined in 0.9% NaCl solution at 36.5℃±1.0℃ using a potentiostat and an electrochemical impedance spectroscope. The potentiodynamic test was performed with a scanning rate of 1.667 mV s⁻¹ from −1,500 to 2,000 mV. A frequency range of 10⁻¹ to 10⁵ Hz was used for the electrochemical impedance spectroscopy (EIS) measurements. The amplitude of the AC signal was 10 mV, and 5 points per decade were used. The morphology and structure of the samples were examined using field-emission scanning electron microscopy and thin-film X-ray diffraction. The elemental analysis was performed using energy-dispersive X-ray spectroscopy. RESULT: The PEO-treated surface exhibited an irregular pore shape, and the pore size and number of the pores increased with an increase in the Mn concentration. For the PEO-treated surface, a higher corrosion current density (I(corr)) and a lower corrosion potential (E(corr)) was obtained as compared to that of the bulk surface. However, the current density in the passive regions (I(pass)) was found to be more stable for the PEO-treated surface than that of the bulk surface. As the Mn concentration increased, the capacitance values of the outer porous layer and the barrier layer decreased, and the polarization resistance of the barrier layers increased. In the case of the Mn/Ca-P coatings, the corroded surface was found to be covered with corrosion products. CONCLUSION: It is confirmed that corrosion resistance and polarization resistance of PEO-treated alloy increased as Mn content increased, and PEO-treated surface showed lower current density in the passive region.