Fabrication and histological evaluation of bone-replacing calcium phosphate cement using NaHCOィイD23ィエD2

由于在破骨细胞产生的弱酸性溶液中，CO3-AP的溶解速度比不含CO3的AP快得多，因此由无碳酸盐磷灰石(AP)到碳酸盐磷灰石(CO3-AP)组成的固化磷灰石水泥(AC)的变化可能会加速固化AC与骨的置换。本研究将NaHCO3添加到AC组分中，研究了添加NaHCO3对水泥凝结性能和凝结质量的影响，作为制备AC的初始步骤，该AC可以比目前的AC更快地被骨替代。当NaHCO3加入AC中时，得到的组质量含有CO3。虽然不是所有的CO3都被并入SET AC中，但是被并入SET AC中的CO3的量随着NaHCO3的加入量而增加。FT-IR测试表明，产物为B型CO3-AP。凝结时间从30min延长到45min，表明NaHCO3对AP的形成有抑制作用。随着NaHCO3的加入，SET AC的径向拉伸强度(DTS)显著降低。扫描电子显微镜观察表明，当NaHCO3加入到AC中时，在AC中形成了细小的晶体。结果表明，随着NaHCO3加入量的增加，固化型AC的结晶度指数随NaHCO3用量的增加而降低。SET AC在弱酸(pH 5.5)中的溶出速率随NaHCO3加入量的增加而增大。随着CO3含量的增加，培养破骨细胞的吸收陷窝数和吸收面积增加。含-AC的4%CO3上的吸收面积是不含碳酸盐的AC的两倍。结果表明，CO3-AP形成的AC易被破骨细胞吸收，在口腔颌面外科、整形外科、整形外科等领域具有广阔的临床应用前景。

Alternation of a composition of set apatite cement (AC) from carbonate-free apatite (CO3-free AP) to carbonate apatite (CO3-AP) may accelerate replacement of the set AC with bone since CO3-AP can be dissolved much faster than CO3-free AP in the weak acidic solution produced by osteoclast. In this investigation, NaHCO3 was added to the AC component and the effects of added NaHCO3 on cement setting behavior and on set mass were studied as an initial step for the fabrication of AC which can be replaced with bone faster than current AC. When NaHCO3 was added to AC, the resultant set mass contained CO3. Although not all CO3 was incorporated in the set AC, the amount of CO3 incorporated into the set AC increased with the amount of added NaHCO3. FT-IR measurement revealed the formation of B-type CO3-AP. The setting time was prolonged from 30 min to 45 min, indicating that NaHCO3 has an inhibitory effect on AP formation. The diametral tensile strength (DTS) of the set AC decreased significantly with the addition of NaHCO3. Scanning electron microscopic observation revealed that fine crystals were formed in the set AC when NaHCO3 was added to AC. As a result, the crystallinity indexes of the set AC measured using powder x-ray diffraction (XRD) and FT-IR decreased with an increase in the amount of added NaHCO3. The dissolution rate of set AC in weak acid, pH 5.5, increased with the amount of added NaHCO3. The number of resorption pits and the resorbed area by cultured osteoclasts increased according to added CO3 content. The resorbed area on 4% CO3 containing-AC was twice as much as carbonate-free AC. The results suggested that CO3-AP-formed AC would be easily resorbed by osteoclasts and have good potential value for its use in wider clinical applications in oral and maxillofacial, plastic and reconstructive surgery.