Controlled crystal growth of calcium phosphate on titanium surface by NaOH-treatment

A simple supersaturated calcification solution (SCS) was used to deposit calcium phosphate (Ca-P) on the surface of NaOH-treated titanium (NaOH-Ti), in order to study the corresponding deposition mechanism of calcium phosphate (Ca-P). No Ca-P coating from SCS was found on titanium without NaOH-treatment, while NaOH-Ti possessed the capability to induce a Ca-P coating on the titanium surface. Octacalcium phosphate (OCP) crystals were first grown on an NaOH-Ti surface, followed by hydroxyapatite (HA) with a [0 0 1] preferential orientation on OCP. It is found that two factors controlled the growth of Ca-P crystals on NaOH-Ti from SCS, First, the surface morphology of NaOH-Ti characterized with crevices seems to be beneficial for inducing a Ca-P coating from SCS; second, the basic hydroxyl, Ti-OH, radical has increased in NaOH-Ti with the increase of treating time and concentration, which facilitate the nucleation of Ca-P crystals. (C) 1999 Elsevier Science B.V. All rights reserved.