The development of apatite cement that has the enhanced speed of bone replacement

首先，制备了最佳粒径的碳酸钙和混合无水磷酸二钙。将得到的粉末混合到中性磷酸氢水溶液中，装入塑料模具中。用粉末x射线衍射法对24小时后的椎间盘进行评价。x射线衍射图显示结晶度较差的磷灰石矿物。其次，我们评估了破骨细胞对椎间盘的吸收。结果，固定椎间盘被破骨细胞吸收。此外，当将固定椎间盘浸入酸溶液中时，我们发现破骨细胞对固定椎间盘的吸收速率与酸量的速率一致。结果表明，含碳酸盐钙的水泥凝片具有比普通磷灰石水泥更快的吸收能力。再次，我们研究了成骨细胞对固定椎间盘骨传导性能的评价。简单地说，我们将成骨细胞播种在固定的椎间盘上，用RT-PCR方法评估成骨细胞的分化情况。结果表明，固定椎间盘能促进成骨细胞的分化。现在我们将固定的椎间盘植入动物骨中进行组织学评价。在较短的时间内，我们没有发现与常规磷灰石水泥相比有显著差异。在更长的时间内，我们正在研究与常规磷灰石相比，固定盘吸收的显著差异。

Firstly, we prepared the best size of carbonate calcium and mixed dicalcium phosphate anhydrate. The obtained powder was mixed into newtral hydrogen phosphate aqueous solution, and was packed into a plastic mould. The disc set after 24 hours was evaluated by means of powder X-ray diffraction. The X-ray diffraction pattern revealed apatitic mineral with poor crystallinity.Secondly, we evaluated the resorption of the disc by osteoclast. As a result, the set disc was resorbed by osteoclast. Furthermore, when the set disc was immersed into acid solution, we found that the rate of resorption on the set disc by osteoclast was consistent with the rate of acid amount. These results showed that the set disc which contained carbonate calcium, had the ability of faster resorption than conventional apatite cement.Thirdly, we studied the evaluation of osteoconductivity on the set disc with osteoblast. Briefly, osteoblast was seeded on the set disc and we evaluated the differentiation of osteoblast by RT-PCR methods. The results showed that the set disc promoted the differentiation of osteoblast.Now we implant the set disc into animal bone to study the histological evaluation. In shorter period, we could not find out the significant difference compared with conventional apatite cement. In longer period, we are studying the significant differences of resorption on the set disc compared with conventional apatite.