Abstract
Calcium phosphate ceramics have been used as synthetic grafts for bone repair. This family of alloplastic grafts is an alternative to allografts (from other individuals from the same specie), autografts (from the same individual) or xenografts (from individuals from other species). Sintered bovine bone is basically composed mainly by hydroxyapatite (HA), Ca10(PO4)6(OH)2 but chemical analyses indicate the presence of Mg. Chemical and heat treatments are generally required to eliminate biological hazard. However, the more crystalline hydroxyapatite, the less resorbable the product is. An approach to have a highly crystalline and still resorbable material is to use additions of alpha or beta tricalcium phosphate, Ca3(PO4)2 , (TCP). The addition of fractions of some bioactive glasses to hydroxyapatite has shown to be effective in promoting its decomposition to tricalcium phosphate. In addition, glass reinforced hydroxyapatite composite are materials with higher compressive strength due to liquid phase sintering. In this study, novel scaffolds based on hydroxyapatite and tricalcium phosphate are presented.
Highlights
Bone is a dynamic tissue, which undergoes healing after severe injuries, since favourable conditions are present
Autografts come from the same individual, whereas allografts are bone from other individuals from the same specie
Bioactive glasses and glass-ceramics are examples of biomaterials used for bone reconstruction
Summary
Bone is a dynamic tissue, which undergoes healing after severe injuries, since favourable conditions are present. Bone grafts can be autogenous, allogenous, xenogenous or alloplastic [2]. Synthetic or alloplastic grafts were first designed to be osteoconductive, i.e. e., able to conduct growth of the newly formed bone tissue throughout the pores of the structure [3,4,5,6]. Bioactive glasses and glass-ceramics are examples of biomaterials used for bone reconstruction. Glass-reinforced hydroxyapatite, GR-HA, is still bioactive and can have higher fracture toughness than pure HA. GR-HA can be produced by mixing HA and bioactive glasses. When a CaO-P2O5 based glass is added to hydroxyapatite (HA) and sintered, the glassy phase reacts with HA. The present phases will depend on the sintering temperature and the glass composition. It is beneficial to have bioresorbable phases like beta tricalcium phosphate (β-TCP) and alpha tricalcium phosphate (α-TCP), as these phases are known to be more soluble than HA [7]
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