Preparation of bioactive titania films on titanium metal via anodic oxidation

Cui, X.; Kim, H.-M.; Kawashita, M.; Wang, L.; Xiong, T.; Kokubo, T.; Nakamura, T.

doi:10.1016/j.dental.2008.04.012

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Volume 25, Issue 1 , Pages 80-86, January 2009

Preparation of bioactive titania films on titanium metal via anodic oxidation

X. Cui
- Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
H.-M. Kim
- Department of Ceramic Engineering, School of Advanced Materials Engineering, Yonsei University 134, Shinchon-dong Seodaemun-gu, Seoul 120-749, Republic of Korea
M. Kawashita
- Center for Research Strategy and Support, Tohoku University, Aoba-ku, Sendai 980-8579, Japan
- Corresponding author. Tel.: +81 22 795 3937; fax: +81 22 795 3937.
L. Wang
- Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
T. Xiong
- Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
T. Kokubo
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
T. Nakamura
- Department of Orthopedic Surgery, Graduate School of Medical, Kyoto University, Shogoin, Kawahara-cho 54, Sakyo-ku, Kyoto 606-8507, Japan

Received 1 May 2007; accepted 15 April 2008.

Abstract

Objectives

To research the crystal structure and surface morphology of anodic films on titanium metal in different electrolytes under various electrochemical conditions and investigate the effect of the crystal structure of the oxide films on apatite-forming ability in simulated body fluid (SBF).

Methods

Titanium oxide films were prepared using an anodic oxidation method on the surface of titanium metal in four different electrolytes: sulfuric acid, acetic acid, phosphoric acid and sodium sulfate solutions with different voltages for 1min at room temperature.

Results

Anodic films that consisted of rutile and/or anatase phases with porous structures were formed on titanium metal after anodizing in H₂SO₄ and Na₂SO₄ electrolytes, while amorphous titania films were produced after anodizing in CH₃COOH and H₃PO₄ electrolytes. Titanium metal with the anatase and/or rutile crystal structure films showed excellent apatite-forming ability and produced a compact apatite layer covering all the surface of titanium after soaking in SBF for 7d, but titanium metal with amorphous titania layers was not able to induce apatite formation.

Significance

The resultant apatite layer formed on titanium metal in SBF could enhance the bonding strength between living tissue and the implant. Anodic oxidation is believed to be an effective method for preparing bioactive titanium metal as an artificial bone substitute even under load-bearing conditions.

Keywords: Titanium, Anodic oxidation, Rutile, Anatase, Apatite