Calcium-phosphate surface coating by casting to improve bioactivity of titanium

In order to improve the bioactivity of titanium, an original surface treatm ent was attempted with the use of a casting technique was attempted. Pure t itanium was cast into a special graphite mold in which the cavity wall was coated with hydroxyapatite (HA) powder. According to analyses of X-ray diff raction and EDX, the existence of HA and CaO and uptake of Ca and P on the surface of the titanium castings were identified. By immersing the specimen in Hank's solution, the concentrations of Ca and P on the surface increase d with immersion time, and the formation of a thin layer with characteristi cs of spherical HA precipitates was observed after 1 week. The concentratio ns of Ca and P elements and the Ca/P ratio on the HA layer increased with i mmersion time. The formation of the HA layer on the titanium cast by this t reatment was significantly accelerated compared with pure titanium. The pre sent surface treatment of Ti is expected to improve early bone fixation of Ti implants. (C) 2001 John Wiley & Sons.