Physicochemical properties of hydroxyapatite/dicalcium phosphate dehydrate bone cement / 中国组织工程研究

ABSTRACT

BACKGROUND:β-tricalcium phosphate (β-TCP) and monocalciumphosphate monohydrate (MCPM) are traditionally considered as reactants for dicalcium phosphate dehydrate (DCPD) bone cement,but little is reported on the hydroxyapatite (HA) as a reactant.OBJECTIVE:To verify whether HA and MCPM can be used to prepare DCPD bone cement and to explore the physicochemical properties.METHODS:The HA and β-TCP were prepared by wet chemical precipitation method,and mixed with appropriate proportion of MCPM.Then,the HA-DCPD and β-TCP-DCPD were obtained by adding a proper amount of curing water.The composition and structure of the two materials were analyzed by X-ray diffraction,the morphology was observed by scanning electron microscope,and the mechanical strength was tested by Instron5567 universal material test machine.These two kinds of materials were placed in simulated body fluid for detecting the weight loss ratio,soaked for 14 days and taken out for X-ray diffraction and scanning electron microscope detection.RESULTS AND CONCLUSION:X-ray diffraction findings indicated that these two kinds of materials both belonged to high-purity DCPD bone cement.Under the scanning electron microscope,β-TCP-DCPD bone cement had dense crystal structure,with less pore number;however,the HA-DCPD bone cement presented with finer grains,loose structure,and higher pore number.With the increase of curing time,the mechanical strength of two kinds of bone cements was correspondingly increased,but the compressive strength of β-TCP-DCPD bone cement was significantly higher than that of HA-DCPD bone cement (P ＜ 0.05).In the simulated body fluid,the weight loss ratio of β-TCP-DCPD bone cement was significantly lower than that of HA-DCPD bone cement (P ＜ 0.05).At 14 days after soaking in the simulated body fluid,a layer of spherical particles that was formed on the surface of both materials was identified as hydroxyapatite by scanning electron microscope observation and X-ray diffraction analysis.In summary,HA-DCPD bone cement has good biodegradability,excellent bioactivity and bone conductivity,but poor mechanical properties.