Bioceramics bioinert ceramics

Bioceramics Bioinert ceramics Bioinert (is not rejected), biocompatible Replacement/repair of teeth, coatings, root pins, crowns... 

In this chapter, we will attempt to trace briefly the long and sometimes anfractuous history of important bioceramics including coatings. Emphasis will be put on the bioinert ceramics alumina and zirconia, as well as on bioactive, that is osseo-conductive calcium phosphates. 

A limited number of contributions dealing with HVSF-sprayed alumina coatings exist. While these contributions appear to have no direct bearing to bioceramic coatings, alumina is considered a bioinert ceramic and, in the future, applications may arise for such coatings in the biomedical realm. 

Nonabsorbable or Relatively Bioinert Bioceramics. 39-2 Relatively Bioinert Ceramics Alumina (AI2O3) Zirconia (Zr02) Carbons... 

In order to be classified as a bioceramic, the ceramic material must meet or exceed the properties listed in Table 39.1. The number of specific ceramics currently in use or under investigation cannot be accounted for in the space available for bioceramics in this book. Thus, this chapter will focus on a general overview of the relatively bioinert, bioactive or surface reactive ceramics, and biodegradable or resorbable bioceramics. 

Relatively bioinert ceramics maintain their physical and mechanical properties while in the host. They resist corrosion and wear and have aU the properties listed for bioceramics in Table 39.1. Examples of relatively bioinert ceramics are dense and porous aluminum oxides, zirconia ceramics, and single phase calcium aluminates (Table 39.2). Relatively bioinert ceramics are typically used as structural-support... 

A strong interest in the use of ceramics for biomedical engineering applications developed in the late 1960 s. Used initially as alternatives to metallic materials in order to increase the biocompatibility of implants, bioceramics have become a diverse class of biomaterials presently including three basic types relatively bioinert ceramics maintain their physical and mechanical properties in the host and form a fibrous tissue of variable thickness surface reactive bioceramics which form a direct chemical bonds with the host and bioresorbable ceramics that are dissolved with the time and the surrounding tissue replaces it. 

Bioinert Relatively bioinert ceramics maintain their physical and mechanical properties while in the host. They are those stable bioceramics that do not react appreciably when they are implanted in the body. The implant does not form a bond with bone. Alumina (a-Al203) is a typical example of ceramic bioinert. Other examples, as we see next, are the zirconia ceramics (Zr02) and pirolitics carbon ceramics. 

The appearance of this type of bioceramics bom of the need to eliminate the interface movement that takes place with the implantation of bioinert ceramics. Consequently, L. L. Hench proposes in 1967 to the U.S.A. Army Medical Research and Development Command, a research based on the modification of the chemical composition of ceramics and glasses so that they have chemical reactivity with the physiological system and form chemical bond between the adjacent tissue and the surface of implant materials. 

Bioceramic materials have developed into a very powerful driver of advanced ceramics research and development. For many years bioceramics, both bioinert materials such as alumina, zirconia and, to a limited extent titania (Lindgren et al., 2009), and bioconductive materials such as hydroxyapatite, tricalcium phosphate and calcium phosphate cements, have been used successfully in dinical practice. In addition, applications continue to emerge that use biomaterials for medical devices. An excellent account of the wide range of bioceramics available today has recently been produced by Kokubo (2008), in which issues of the significance of the structure, mechanical properties and biological interaction of biomaterials are discussed, and their clinical applications in joint replacement, bone grafts, tissue engineering, and dentistry are reviewed. The type and consequences of cellular responses to a variety of today s biomaterials have been detailed in recent books (Di Silvio, 2008 Basu et al., 2009 Planell et al., 2009). 

Structural ceramics They are bioceramics of high mechanical strength and generally bioinerts. Typical examples are alumina (a-Al203) and zirconia (Zr02). 

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