Fabrication of self-setting foam for bone graft material

磷酸钙是骨移植材料中不可缺少的。各种方法可用于制造多孔HAP泡沫。在这些方法中，已知只有泡沫方法允许类似于松质骨的三维完全互连的多孔结构。但是，使用泡沫方法很难使这种泡沫与骨缺损的形状相同。小尺寸泡沫硬化后互相填充，以消除缺陷.我们尝试用小粒径的α-TCP泡沫研制自凝泡沫。这种α-TCP泡沫用NaH_2PO_4溶液或蒸馏水硬化。在室温下用NaH_2PO_4溶液凝结时间约为5小时，在200℃下用蒸馏水凝结时间约为24小时。固化后的化学产品为DCPD与NaH_2PO_4溶液，HAP与蒸馏水。凝固后，α-TCP泡沫表面形成长约20 ~ 50 μm的针状晶体。针状晶体在凝固反应过程中相互渗透。这有助于与牙科石膏相同的机制。

Calcium phosphate faom is exerent for bone graft material. Various methods are applicable for the fabrication of porous HAP foam. Among these method, only the foam method is known to permit three-dimensional fully interconnected porous structure similar to cancellous bone. But, it is very difficult to make this foam same as a shape of bone defect using foam method. Small size foam hardened each other after filling to the defect clear this problem. We tried to develop the self setting foam using small size particle of α-TCP foam. This α-TCP foam hardened with NaH_2PO_4 solution or distilled water. Setting time was about 5 hours at room temperature with NaH_2PO_4 solution, and 24hours at 200℃ with distilled water. Chemical product after setting was DCPD with NaH_2PO_4 solution, and HAP with distilled water. After setting, needle like crystals which length was about 20 to 50 μm were formed on the surface of α-TCP foam. Needle like crystals penetrated each other during the setting reaction. This contributed to set in the same mechanism as dental plaster.