Alumina bioceramic

The Weibull modulus of an alumina bioceramic is given as 8.4. (a) What does a value of m = 8.4 imply (b) For an implant made out of a metal the value of m 100. What implications would this have for lifetime predictions for the metal component compared to the alumina component (c) How does the value of m affect... 

Single oxide ceramics, e.g. aluminium oxide (AI2O3, alumina) and zirconium dioxide (Zr02, zirconia), are bioceramics of an inert nature. An inert ceramic does not form a bonding to bone similar to those bioceramics of bioactive nature. Alumina bioceramics are in the pure aluminium oxide form, whereas zirconia bioceramics are partially stabilized by additional oxides, e.g. yttrium oxide, calcium oxide or magnesium oxide. 

J. (1990) Alunrinium release as a new factor in the estimation of alumina bioceramic implants. Clin. Mater., 5, 167-175. 

The most common application of alumina bioceramics is in the area of orthopaedics as component in hip and knee prostheses. The first clinical use of total hip prosthesis with an aliunina head and alumina socket was in 1971. The long term coefficient of the pair alumina/alumina and the wearing down index decrease with time and approaches the value of a normal healthy joint [18],... 

Nevertheless, recently studies of new materials of TZP, doped with yttria tested in simulated body fluids and in animals, have shown slight decreases in fracture toughness and Young Modulus [34-36]. The observed strength, after two years, is sill much higher that the strength of alumina bioceramic tested under similar conditions. Because the zirconia/zirconia... 

Wear rate was measured for square discs of alumina, zirconia and two kinds of alumina/zirconia nano-composite ceramics. The mating face was made of alumina (BIOCERAM NPX Kyocera Corporation) with the same quality as the alumina femoral components. Mechanical properties of the test materials and the reference material are listed in Table 1. Typical grain size of the alumina was 3 pm and that of the zirconia was 0.8 pm. The grain size of composite ceramics was similar to zirconia. 

Webster, T. J., Siegel, R. W., and Bizios, R., An in vitro evaluation of nanophase alumina for orthopaedic/dental applications, in Bioceramics 11 11th International Symposium on Ceramics in Medicine (R. Z. LeGeros and J. P. LeGeros, Eds.), p. 273-276. World Scientific, New York, 1998. 

Table 1 Uses of Alumina Solid alumina Furnace components Catalyst substrates Electronics substrates Electrical insulators Cutting tools Bearings Spark Plugs Arc lamp tubes Laser hosts Gem stones Alumina powders Abrasives Catalyst pellets Alumina coatings Oxidation protection of aluminum and aluminum alloys Capacitors Transisitors Bioceramics Alumina fibers Thermal insulators Fire retardation Alumina as a component of...

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. 

Regrettably, no biomaterial is known to date that is both mechanically stable and sufficiently osseoinductive classic bioceramics such as alumina or stabilised zirconia are strong but bioinert, osseoconductive hydroxyapatite is mechanically weak and essentially non-resorbable, whereas the even weaker osseoconductive tricalcium phosphate is resorbable (Figure 3.9). 

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. 

Suzuki, M., Guimaraes, M.V.M., Marin, C., Granato, R., Gil, J.N., and Coelho, P.G. (2009) Histomorphometric evaluation of alumina-blasted/acid-etched and thin ion beam-deposited bioceramic surfaces an experimental study in dogs. J. Oral Maxillofac. Surg., 67 (3), 602 - 607. 

Figure 7.36 Traces obtained during scratch testing (Revetest Xpress Plus with Rockwell indenter) of plasma-sprayed bioceramic coatings consisting of 100% HAp (a), 72% HAp+ 18% YSZ+ 10% alumina (b),...

Cerahrx . [Condea Chemie GmbH] Ultra-pure aluminas used for translucent cerairtics, syndietic sapphire glass, in the laser industry, fm heavy- ty cutting tocds, for bioceramics. 

There is a high potential for using bioceramics in bone tissue replacement and regeneration. The study shows possibility of treatment of bone defects using the porous alumina grafts, calcite porous scaffolds, polymer/ceramic biocomposite scaffolds, and ceramic coatings. 

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

Ceramics used in fabricating implants can be classified as nonabsorbable (relatively inert), bioactive or surface reactive (semi-inert) [Hench, 1991,1993] and biodegradable or resorbable (non-inert) [Hentrich et al., 1971 Graves et al., 1972]. Alumina, zirconia, silicone nitrides, and carbons are inert bioceramics. Certain glass ceramics and dense hydroxyapatites are semi-inert (bioreactive) and calcium phosphates and calcium aluminates are resorbable ceramics [Park and Lakes, 1992]. 

Dorlot J.M., Christel R, and Meunier A. 1988. Alumina hip prostheses long term behaviors. In Bioceramics. Proceedings of 1st International Symposium on Ceramics in Medicine. H. Oonishi, H. Aoki, and K. Sawai (Eds.), pp. 236 301. Ishiyaku EuroAmerica, Inc. Tokyo. 

Heimke G. 1992. Use of alumina ceramics in medicine. In Bioceramics,Vol. 3. J.E. Hulbert and S.E Hulbert (Eds.), pp. 19-30. Rose Hulman Institute of Technology, Terre Haute, IN. 

Bioceramics are used in the human body. The response of these materials varies from nearly inert to bioactive to resorbable. Nearly inert bioceramics include alumina (AI2O3) and zirconia (Zr02). Bioactive ceramics include hydroxyapatite and some special glass and glass-ceramic formulations. Tricalcium phosphate is an example of a resorbable bioceramic it dissolves in the body. Three issues will determine future progress ... 

Bioceramics are ceramics used for the repair and reconstruction of human body parts. There are many applications for bioceramics currently the most important is in implants such as alumina hip prostheses. Alumina is classified as an inert bioceramic because it has very low reactivity in the body. However, bioactive materials have the ability to bond directly with bone. The advantages are... 

Table 16.11 Data from Hulbert, S.F. (1993) The use of alumina and zirconia in surgical implants, in An Introduction to Bioceramics, edited by L.L. Hench and J. Wilson, World Scientific, Singapore, p. 30.

Hendrich C., S. Goebel, C. Roller, et al. 2003. Wear performance of 28 millimeter femoral heads with the Harris-Galante cup Comparison of alumina and cobalt chrome. In Bioceramics in joint arthroplasty, 8th BIOLOX symposium proceedings. H. Zippel and M. Dietrich, Eds. Darmstadt, Germany Steinkopff Verlag. 

Schwammlein D., R. Schmidt, N. Schikora, et al. 2002. Migration patterns of press-fit cups with polyethylene or alumina liner—a randomized clinical trial using radiostereoanalysis. In Bioceramics in joint arthroplasty, proceedings of the 7th international BIOLOX symposium. J.P. Garino and G. Willmann, Eds. Stuttgart, Germany Thieme. 

Property ASTM F 603-83 DIN 58 8353 Frialit bioceramic alumina according to ISO/DIS 13356 Prozyr zirconia... 

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