Study Of The Injectable Magnesium-Calcium Phosphate Cements

The rehabilitation and reconstruction of human irregular bone\unstable fracture and later osteoporosis fracture are always the problem in the field of bone repairment. Aim at the specific scientific problems of calcium-phosphate based inorganic biomaterials which is collapsed in vivo and doesn't have cohesiveness, and with noninvasive or minimally invasive surgery on fixing irregular bone injuries and promoting regeneration as the entry point, the goal of the research presented in this dissertation is to design and prepare one kind of magnesium/calcium-phosphate based biomaterials for hard tissue repair, some other properties has been discussed including the performance during in the gelation, injection, adhesive, washing-out resistance and biodegradability in vitro.According to former research in study, the major constituents of injectable magnesium-calcium phosphate cements (IMPC) were entrenched including potassium phosphate,MgO, calcium phosphate cementitious materials, et al. And the retarder used in the cements is glucose, one of monosaccharides, because of its retarder, easily dissolved in the water and good coagulation retarding effect. The initial formula of cement was determined by evaluating the effect the Ca/Mg ratio, the content of retarder and the ratio of liquid and solid on its compression strength, setting time, injective, anti-washout rate, cohesive strength.The hydration dynamics and hydration mechanism of magnesium-calcium phosphate cement were discussed according to XRD, EDS, SEM and C-80 Micro Calorimeter. The formula was optimized by the orthogonal experiments of factors and levels,and the best formula has been gained. Finally, degradation performance of IMPC was evaluated by studying the changing patterns of weight loss, compression strength, Ca2+ion concentration, pH value and the morphology and quantity of apatite produced during degrading, which were studied by AAS,SEMQ. The IMPC of best formula would meet clinical needs, with the compression strength (22.3±0.5MPa), setting time (5.5±1.0min), injective (94.1±2.0%), anti-washout rate (92.2±1.2%), cohesive strength(2.21±0.3MPa). The apatite on samples delivered the information of the IMPC's bioactivity and degradability in vivo. The IMCP, one kind of injectable in-situ curing adhensive, prepared in this experiment has fine injectability, biodegradability, excellent washing resistance, suitable short setting time, good washing-out resistance, bonding strength.which is the innovation of this research. It is widely used in many domains such as dental/bone-repair, bone-substitute and adhesive materials in noninvasive or minimally invasive surgery and so on, exhibiting the expansive applying future。...