Plasma electrolytic oxidation of titanium and improvement in osseointegration

Abstract

Abstract Reducing the osseointegration time for biomedical titanium implants in surgical patients is an important goal. However, a huge controversy exists over the effectiveness of osseointegration of the surface layer by plasma electrolytic oxidation (PEO), which is a widely favored surface modification for titanium‐based implants. In this study, various surface coatings, including anatase‐TiO 2 (A‐TiO 2 ), rutile‐TiO 2 (R‐TiO 2 ), hydroxyapatite (HAp), strontium‐containing hydroxyapatite (Sr‐HAp), and dual‐phase HAp‐TiO 2 were synthesized on titanium implants by PEO. A comparative study of osseointegration performance (both in vitro and in vivo ) and bone/implant adhesion strength conducted using push‐out thrust tests were demonstrated. The in vitro experimental test results agree strongly with the in vivo test results: the dual‐phase HAp‐TiO 2 coating exhibits the superior cell adhesion and differentiation condition among all of the coatings in the in vitro tests and therefore has the highest push‐out bonding strength of 5.37 MPa after 12 wk of implantation in the in vivo test. The HAp‐containing coatings benefit from its bioactivity and therefore perform the others in terms of long‐term osteocyte growth (from the in vitro results) and the extent of osseointegration (from the in vivo results). The dual‐phase HAp‐TiO 2 coating provides the advantages of both the bioactive HAp and structural enhancement by the TiO 2 , effectively promoting osseointegration. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.