Poly bone applications

Poly(Dat-Tyr-Hex carbonate) is a slowly degrading, strong and ductile material. This material may be applicable in situations where a mechanical support function is needed for an extended period of time such as in small bone fixation devices (bone pins or screws). The reproducible fabrication of such devices by injection molding is particularly easy due to the amorphous character of poly(Dat-Try-Hex carbonate). 

Another example of composites in biomedical applications is graphite-fiber-reinforced bone cement. Self-curing poly(methyl methacrylate), PMMA, is used extensively as a bone cement in orthopedic surgery for fixation of endoprostheses... 

Early reports of the biomedical use of poly(lactic acid) date back to the 1960s [3, 175]. Since then, PLA has gained widespread application in the medical field, for use in sutures [8], drug delivery devices [15, 17, 24, 59-90], prosthetics, scaffolds, vascular grafts, and bone screws, pins and plates for temporary internal fracture fixation [10-13]. Good mechanical properties and the fact that it de-... 

Weber, F. E., Eyrich, G, Gratz, K. W., Maly, F. E., and Sailer, H. F. (2002), Slow and continuous application of human recombinant bone morphogenetic protein via biodegradable poly(lactide-co-glycolide) foamspheres, Int. J. of Oral Maxillofacial Surg., 31, 60-65. 

Kikuchi, M., Koyama, Y, Takakuda, K., Miyairi, H., Shirahama, N., and Tanaka, J., In vitro change in mechanical strength of 3-tricalcinm phosphate/copolymer-ized poly-L-lactide composites and their application forgnided bone regeneration, J. Biomed. Mater. Res., 62, 265, 2002. 

The development of unsaturated polyanhydrides responded to the necessity of improving the mechanical properties of the polymers in applications such as the temporary replacement of bone. " Unsaturated polyanhydrides, prepared by melt or solution polymerization, include homopolymers of fumaric acid (FA), acetylene-dicarboxylic acid (ACDA), and 4,4 -stilbenzenedi-carboxylic acid (STDA). The chemical structures of poly(FA) and poly(ACDA) are shown in Table 1. These polymers are highly crystalline and insoluble in common organic solvents. The double bonds of these monomers make them suitable for further crosslinking to improve mechanical properties of polyanhydrides. When copolymerized with aliphatic diacids, less crystalline polymers with enhanced solubility in chlorinated solvents result. 

Porter JR, Henson A, Popat KC (2009) Biodegradable poly(epsilon-caprolactone) nanowires for bone tissue engineering applications. Biomaterials 30(5) 780-788... 

Most joint replacements utilize polymers to some extent. Finger joints usually are replaced with a poly(dimethylsiloxane) Insert and over h00,000 such replacements are made each year (l). More recently a poly(1, -hexadiene) polymer has been tried in this application (l). Many other parts of the hand, such as the bones, have also been replaced by silicone rubber. Other types of joints, such as the hip or the knee, often involve the contact of a metal ball or rider on a plastic surface which is usually made from high density, high molecular weight polyethylene. These metal and plastic parts are usually anchored in the body using a cement of poly(methyl methacrylate) which is polymerized in situ. Full and partial hip prostheses are implanted about... 

Polyanhydrides have been developed into various systems with mainly bone tissue engineering applications in mind. These polymers have mechanical strength much lower than that of bone but have been combined with other polymers, such as poly(imide)s, to resolve this problem. Polyanhydrides have been developed into photo-cross-linkable systems, based on dimethacrylated anhydrides, and also injectable systems, but little interest into these polymers with regard to tissue engineering has been taken in the recent past [82]. 

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