Zirconia clinical applications

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). 

The zirconia was CAD/CAM machined from presintered zirconia blocks and then partially reduced in size in some areas for the application of a porcelain veneer. The core ceramic was colored, sintered, and then the veneer was then applied. All processing steps were carried out in accordance with manufacturer s guidelines. The clinical aspects of this case have been documented by Karl and Bauemschmidt There were two main intersecting crack systems as shown in Figure 15a. The first crack was a very smooth and almost featureless thermal crack... 

The 2001 recall has not, however, dampened the general enthusiasm for ceramic materials in orthopedics. Alumina is currently the ceramic material of choice for orthopedic applications, either for articulations with UHMWPE or for use in COC alternate bearings. Starting at the end of 2002, a new alumina composite material (BIOLOX Forte CeramTec, Plochingen, Germany) has been available as a femoral head material (Merkert 2003). This ceramic composite, consisting of 75% alumina matrix, is reinforced by 25% zirconia. The improved strength of this new ceramic composite, in comparison with alumina and zirconia, is summarized in Table 6.2. Clinical studies are still needed to determine the effectiveness and reliability of this new biomaterial. 

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