title: Development of a glass reinforced hydroxyapatite with enhanced mechanical properties. The effect of glass composition on mechanical properties and its relationship to phase changes.
abstract: Utilizing glasses of the types xNa2O-(1-x)P2O5 and xCaO-(1-x)P2O5 (where x = 0.2, 0.3, and 0.5), a systematic study of the effect of increasing network modifying oxides in glasses was made on the mechanical properties of a glass reinforced hydroxyapatite, at glass additions of 2.5 and 5 wt%. For the soda type glass, phase changes were promoted much more readily compared to the lime type glass. This was true for both 2.5 and 5 wt% additions of glass. For the lime type glass, considerable differences between the effects of 2.5 and 5 wt% additions were seen. At 5 wt%, the increased amount of liquid phase present promotes an increased level of phase inversion to alpha and beta tricalcium phosphate. At 2.5 wt%, a larger percentage of the HA remains stable at higher temperatures. Furthermore, the effect of the composition may be seen. As the mol% of network forming oxide increases, (i.e., the Ca/P ratio moves towards 1.67, (the ratio for HA) the HA remains more stable. This is seen in the maintenance of both the HA phase and also the enhanced mechanical properties.
authors.affiliation: IRC in Biomedical Materials, Queen Mary and Westfield College, London, U.K.
authors.forename: J C
authors.initials: JC
authors.lastname: Knowles
authors.forename: W
authors.initials: W
authors.lastname: Bonfield
mesh_terms: D001672:Biocompatible Materials; D017886:Durapatite; D005898:Glass; D010087:Oxides; D010758:Phosphorus; D017553:Phosphorus Compounds; D013314:Stress, Mechanical; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D010087:Oxides; D017553:Phosphorus Compounds; D010758:Phosphorus; C012500:phosphorus pentoxide; D017886:Durapatite