Enhancement of bone mineral formation on Ti6Al4V surface by PM-EDCLT combined with acid etching

Abstract

For Bone-anchored limb prostheses, osseointegration plays a significant role in the mechanically stable interface between bone and implants. Titanium alloy is the most usable alloy for hard tissue replacement. The drawbacks of the titanium implant are corrosion, leaching and poor osseointegration. In this research, powder mixed (hydroxyapatite) - electric discharge-assisted centreless turning (PM-EDCLT) (Impulse current- 5amp, duty factor- 57%, hydroxyapatite concentration 18 g/l, and rpm-360) and acid etching (solution – HF: HNO3: H2O = 1:2:50) were used for the surface modification of screw-fit implants. Average surface roughness value maximum in PM-EDCLT machined surface (1.249 µm) followed by PM-EDCLT machined + 5 min. Acid etching (1.055 µm), PM-EDCLT machined + 10 min. Acid etching (0.9829 µm), PM-EDCLT machined + 15 min. acid etching (0.8223 µm), bare surface with 10 min. Acid etching (0.2866 µm), 15 min. acid etching (0.2714 µm) and 5 min. Acid etching (0.1896 µm). Investigations using Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) proved that the deposited layer on the powder-mixed EDCLT machined sample was hydroxyapatite. After sinking samples in the Simulated Body Fluid (SBF) solution, it was concluded that the percentage of bone minerals like oxide, Ca, and P deposition increases after increasing the acid etching time on the PM-EDCLT machined surfaces. Little effect was found on the deposition of bone minerals on the surface of acid etching only by increasing the etching time. There is a clear trend of decreasing the contact angle with increasing the acid etching time on the PM-EDCLT surfaces.