Apatite formation on bioactive zirconium metal prepared by chemical treatment.

Bioactive metallic materials, which can directly bond to living bone, are badly needed in dental and orthopedic implants for better long-term results. Forming a layer of bone-like apatite on the surface of the metal is one of the most promising methods to increase its bioactivity. This study creates a new chemical treatment for zirconium metal to induce apatite formation in a simulated body fluid (SBF), and analyzes the apatite layer by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). Zirconium samples were soaked in 10% CuCl2 aqueous solution at 80 degrees C for 72 hours, heat-treated at 500 degrees C for one hour and soaked in SBF for various periods. An apatite-like layer appeared on the zirconium surface as early as three days in SBF, and increased with immersion time. EDS and FTIR confirmed that the deposited layer was apatite. This implies that bioinert zirconium metal can become bioactive by forming an apatite layer in a simulated body fluid after a suitable chemical treatment. The ZrOOH+ hydrogel layer produced on the zirconium surface by CuCl2 and heat-treatments is thought to induce the apatite formation.