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This Defense Intelligence Agency reference document, dated 7 January 2010 and prepared under the Acquisition Threat Support series, surveys biomaterials used in medicine. It covers biocompatibility, biosensor membranes, silicones, Teflon, biodegradable polymers, hydrogels, titanium, bioceramics, tissue constructs, cardiovascular stents, contact lenses, drug delivery and dialysis. It concludes that biomaterial performance underlies many medical devices, that the industry is slow to adopt new materials because of testing costs, and that innovation mainly involves new applications of established materials.
UNCLASSIFIED//P8R: 8PPllltlJL Wllil& GNlr.f Two common ceramics used in dentistry and hip prostheses are alumina and hydroxyapatite (HA). HA is a major component of the inorganic compartment of bone. Commercially prepared HA is processed using a technique of phosphoric acid and hydrothermal exchange that produces a porous, "bone-like" morphology in the resulting structure. Figure 16 shows this result. When implanted ·\ ··!:!I-. 1.. • into bone defects, HA supports bone growth through the pores and, thus, becomes an intermediate scaffold, as well as an eventual support matrix. ". .. .. Hydroxyapatite composites have been successfully used to repair, reconstruct, and replace diseased or damaged body parts, especially bone. They have been used in vertebral prostheses, intervertebral spacers, bone grafting, middle-ear bone replacements, and jawbone repair. Figure 16. Hydroxyapatite Porous Bane.:.Llke Structure After Commercial Processing Aluminum oxide, or alumina (A'2OJ), has been used in orthopedic surgery for more than 20 years as the joint surface in total hip prostheses because of its exceptionally low coefficient of friction and minimal wear rates. Alumina has excellent corrosion resistance, good biocompatibility, high strength, and high wear resistance, making it ideal for orthopedic applications. Other bioceramics include coral skeletons, which can be transformed into hydroxyapatite by high temperatures. Their porous structure allows relatively rapid ingrowth of living cells at the expense of initial mechanical strength. The high temperature also burns away any organic molecules, such as proteins, preventing graft-versus-host disease and rejection. Bioceramics made from a calcium phosphate material containing tiny pores have been used to coat metal joint implants or as unloaded space fillers for bone Ingrowth. Tissue ingrowth into the pores occurs, with i2 Figure 17. Bloceramic Used in Artificial Hip Replacement Component UNCLASSIFIED'/,SF&lil: GPPIIIAL t,81!!! 9HL I
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 32 pages are in the text index: search them above, or from the library's search.