CLINICAL USE OF HYDRAULIC PROPERTY OF HYDROXYAPATITE THERMAL DECOMPOSITION PRODUCT

羟基磷灰石热产物通过与水溶液（HAp水泥）混合而硬化。固化后，HAp水泥再次变成纯羟基磷灰石。研究了这种新生物材料的（1）骨亲和性，（2）机械强度，（3）生物安全性，（4）在卵巢切除大鼠股骨中的组织学反应。（1）将羟基磷灰石骨水泥注入28只家兔股骨。通过注射后2、4、9和12周的X-射线衍射证实注射的分解产物是固体和纯HAp。组织学检查显示，注射后两周以上，与HAp骨水泥表面直接接触的新骨形成。HAp水泥显然对骨具有良好的亲和力。（2）将HAp骨水泥注入兔股骨后3天、1周、4周、8周测定其力学强度。从注射部位切割股骨进行压缩试验，结果显示硬化的HAp骨水泥在压缩下不会断裂 ...更多信息 离子力高达50 MPa，强度相当于PMMA的70%。在推出测试中，HAp骨水泥比PMMA骨水泥更坚固。(3)We研究了HAp骨水泥的生物安全性。在急性试验中，将从保存在盐水中的HAp骨水泥中提取的水注射到大鼠的静脉中。未见急性毒性。在亚急性试验中，将HAp粘固剂插入大鼠的皮下、腹膜内和肌内组织中。这些大鼠在注射后1周、2周和4周处死。一般情况、血液学检查和组织学检查均未显示HAp骨水泥的亚急性毒性。在慢性试验中，使用与（1）相同的方法将HAp骨水泥注射到18只家兔中。一半的兔子在26周和一半的52周被处死。所考察的项目与亚急性试验相同，表明HAP骨水泥无慢性毒性。（4）将HAp骨水泥注入去卵巢大鼠股骨（大鼠骨质疏松模型）。注射后8周以上，在注射部位观察到新骨形成，而对照组大鼠为4周。但即使在去卵巢大鼠中，新骨形成的面积也逐渐增加。提示HAp骨水泥具有良好的骨传导性，有望作为一种生物活性骨水泥成功地应用于临床。少

Hydroxyapatite thermal product was hardened by mixing with water solution (HAp cement). After hardening, HAp cement became pure hydroxyapatite again. This new biomaterial was investigated with respect to (1)affinity to bone, (2)mechanical strength, (3)biological safety, and (4)histological reaction in the ovariectomized rat's femur.(1)HAp cement was injected into the femora of twenty-eight rabbits. The injected decomposition product was confirmed to be solid and pure HAp by X-ray diffraction of two, four, nine and twelve weeks after injection. Histological examination revealed new bone formation in direct contact with the surface of HAp cement more than two weeks after injection. HAp cement apparently has a good affinity to bone.(2)The mechanical strength of HAp cement was measured three days, one, and four, and eight weeks after injection into the femur of rabbits. A compression test with femur cut from the injected site revealed that hardened HAp cement did not break under a compress … More ion force up to 50MPa; that strength was corresponds to 70% of PMMA. HAp cement was stronger than PMMA cement in the case of a push-out test. (3)We investigated the biological safety of HAp cement. In the Acute test, water extracted from HAp cement preserved in a saline water was injected into the vein of rats. No acute toxicity was seen. in the Subacute test, HAp cement was inserted into the subcutaneous, intraperitoneal, and intramuscular tissues of rats. Those rats were sacrificed one, two, and four weeks after injection. General state, blood examination, and histological inspection didn't indicate subacute toxicity of HAp cement. In the Chronic test, HAp cement was injected into eighteen rabbits using the same method as (1). Half the rabbits were sacrificed twenty-six and half fifty-two weeks. The items investigated were the same as in the subacute test, and it was revealed that HAP cement has no chronic toxicity.(4)HAp cement was injected into the femur of ovariectomized rats (an osteoporotic model in rats). New bone formation was seen at the injected site more than eight weeks after injection, in contrast to four weeks in the control rats. But even in the ovariectmized rats, the area of new bone formation increased gradually. That indicated HAp cement also has a good osteoconductility.It is expected that HAp cement can be successfully applied clinically as a bioactive bone cement. Less