Promoted hydroxyapatite nucleation on titanium ion-implanted with sodium

Precipitation of hydroxyapatite on titanium from aqueous solution offers th e possibility of creating biologically active coatings for bone fixated imp lants by mimicking the physiological properties of the bone. While solution -related factors have been well established, the research into surface-rela ted stimuli for promoting hydroxyapatite nucleation is still underway. In t he present work titanium surfaces were pretreated by implantation of sodium ions yielding sodium titanate incorporated within the surface layer with c oncentration, depth distribution, and morphology depending on the parameter s of the ion implantation and the subsequent thermal treatment. Such ion-im planted surfaces were observed to promote hydroxyapatite nucleation and gro wth from simulated body fluid. Surface properties were studied using spectr oscopic and microscopic methods. The mechanisms of heterogeneous nucleation of hydroxyapatite were discussed in terms of the electrical double layer. (C) 1999 Elsevier Science B.V. All rights reserved.