Processing and properties of hydroxyapatite-based biomaterials for use as hard tissue replacement implants
- PDF / 746,058 Bytes
- 24 Pages / 612 x 792 pts (letter) Page_size
- 12 Downloads / 230 Views
MATERIALS RESEARCH
Welcome
Comments
Help
Processing and properties of hydroxyapatite-based biomaterials for use as hard tissue replacement implants Wojciech Suchanek and Masahiro Yoshimura Center for Materials Design, Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226, Japan (Received 3 February 1997; accepted 25 July 1997)
This paper reviews the past, present, and future of the hydroxyapatite (HAp)-based biomaterials from the point of view of preparation of hard tissue replacement implants. Properties of the hard tissues are also described. The mechanical reliability of the pure HAp ceramics is low, therefore it cannot be used as artificial teeth or bones. For these reasons, various HAp-based composites have been fabricated, but only the HAp-coated titanium alloys have found wide application. Among the others, the microstructurally controlled HAp ceramics such as fibers/whiskers-reinforced HAp, fibrous HAp-reinforced polymers, or biomimetically fabricated HAp/collagen composites seem to be the most suitable ceramic materials for the future hard tissue replacement implants.
I. INTRODUCTION
There is a necessity for replacing bone substance which has been lost due to traumatic or nontraumatic events. The lost bone can be replaced by endogenous or exogenous bone tissues, which is connected with several problems. The use of endogenous bone substance involves additional surgery1 ; moreover, the endogenous bone is available only in limited quantities.2 The major disadvantage of exogenous bone implants is that they may be rejected by the human body, diseases may be transmitted together with the implant,2 also the clinical performance of exogenous bone is considerably inferior to fresh endogenous graft material.1 For these reasons, there is a growing need for fabrication of artificial hard tissue replacement implants. The biomaterials industry worldwide has an annual turnover of $2.3 billion in the field of hard tissue repair and replacement (total of $12 billion).3 There is currently a projected growth rate of 7–12% per annum for biomaterials in clinical applications.3 Although the biomaterials sector is expanding, it is expected that the volume of materials required will never exceed tens of tons, as compared with thousands of tons for other developing engineering markets.3 Metals have been widely used for major loadbearing orthopedic applications.4 There are, however, various problems related to metallic materials in the human body due to corrosion, wear, and/or negative tissue reaction.5 Almost all metallic implants are encapsulated by dense fibrous tissue which prevents proper distribution of stresses and may cause loosening of the implant.5 Therefore, several ceramic materials have been clinically applied.4–6 Among them, ZrO2 and Al2 O3 exhibit high mechanical strength and good biocompatibility but, like the metals, belong to bioinert materials. [Types of implant-tissue response, 94
http://journals.cambridge.org
J. Mater. Res., Vol. 13, No. 1, Jan 1998
Data Loading...
