Hydroxyapatite, implant material

X-ray diffraction (XRD) experiments, 25 XRD of Lao.6Sro.4FeC>3, 33 Hydroxyapatite, implant material, 145... 

An important development of orthopaedic implants has been the development of artificial composites, which when combined with biomolecules will induce osteogenesis. The properties of hydroxyapatite (HA) materials have been studied over the years with a view to increasing elasticity. Because biocompatibility has been a problem when HA has been combined with various polyethylenes and polysulphones, polyhydroxyalkanoates (PHAs) and its chemical composites, a polymer of hydroxybutyric acid (PHB), copolymers of hydroxybutyric acid and... 

Calcium phosphate A family of calcium- and phosphate-containing materials of synthetic or natural origin which are utilized for implants and bone augmentation purposes. The most prominent materials are the tricalcium-phosphate- and hydroxyapatite-based materials, although most synthetic implants are a mixture of the various compositions. 

W. Bonfield, M.D. Grynpas, A.E. Tully, Hydroxyapatite reinforced polyethylene—a mechanically compatible implant material for bone replacement. Biomaterials 2, 185-186 (1981)... 

Niinomi, M. Cyto-toxicity and fatigue performance of low rigidity titanium alloy, Ti-29Nb-13Ta-4.6Zr, for biomedical apphcations. Biomateiials, 24,2673-2683(2003). Niespodziana, K., Jurczyk, K., Jakubowicz, J., and Jurczyk, M. Fabrication and properties of titanium-hydroxyapatite nanocomposites. Mater. Chem. Phys., 123,160-165 (2010). Noort, R.V Titanium The implant material of today. J. Mater. Sci., 22,3801-3811 (1987). Narayanan, R., Seshadri, S.K., Kwon, T.Y., and Kim, K.H. Electrochemical nano-grained calcium phosphate coatings on Ti-6AMV for biomaterial apphcations. Scripta Mater., 56, 229-232 (2007). 

In recent years, biocomposite materials are also being developed (Fig. 23.2b-c). These materials are composed of a combination of the previously listed polymers and osteoconductive materials, such as beta-tricalcium phosphate ( -TCP) or hydroxyapatite (HA). In particular, -TCP that can be used as synthetic implant material has appropriate ultrastructural properties for cell adhesion [30]. 

Hydroxyapatite ceramics have been found to be one of the best implantation materials successfully used in bone surgeries and dentistry. This ceramics allows for their easy connection with other types of materials which creates opportunity for development of composites for medical applications. 

Zinc added to bioglasses improve their chemical durability, mechanical properties and endows antimicrobial activity moreover, the release of small concentration of zinc incorporated into an implant material promotes bone formation around the implant and accelerates recovery of the patients, improve adhesion of denture adhesives, etc... Still, it is important to control the Zn releasing rate in order to prevent adverse reactions and to optimize the glass composition to reduce glass degradation without affecting the hydroxyapatite deposition. 

Afonso, A., Santos, J. D., Vasconcelos, M., Branco, R., and Cavalheiro, J. 1996. Granules of osteoapatite and glass-reinforced hydroxyapatite implanted in rabbit tibiae. Journal of Materials Science Materials in Medicine 7 507-10. 

High-density polyethylene (HDPE)-hydroxyapatite (HA)-aluminum oxide (AI2O3) composite-based implant materials showed great biocompatibility for orthopedic appUcations, especially for bone replacement (Tripathi et al 2013) (Table 4.1). 

---