Calafiori Anna Rita, Marotta Marcello, Nastro Alfonso, Martino Guglielmo
Department of Cell Biology, University of Calabria, Italy.
Biomed Eng Online. 2004 Mar 22;3(1):8. doi: 10.1186/1475-925X-3-8.
Calcium phosphate manufactured samples, prepared with hydroxyapatite, are used as either spacers or fillers in orthopedic surgery, but these implants have never been used under conditions of mechanical stress. Similar conditions also apply with cements. Many authors have postulated that cements are a useful substitute material when implanted in vivo. The aim of this research is to develop a low cristalline material similar to bone in porosity and cristallinity.
Commercial hydroxyapatite (HAp) and monetite (M) powders are mixed with water and compacted to produce cylindrical samples. The material is processed at a temperature of 37-120 degrees C in saturated steam to obtain samples that are osteoconductive. The samples are studied by X-ray powder diffraction (XRD), Vickers hardness test (HV), scanning electron microscopy (SEM), and porosity evaluation.
The X-ray diffractions of powders from the samples show patterns typical of HAp and M powders. After thermal treatment, no new crystal phase is formed and no increase of the relative intensity of the peaks is obtained. Vicker hardness data do not show any relationship with treatment temperature. The total porosity decreases by 50-60% according to the specific thermal treatment. Scanning electron microscopy of the surfaces of the samples with either HAp 80%-M 20% (c) or Hap 50%-M 50% (f), show cohesion of the powder grains.
The dissolution-reprecipitation process is more intesive in manufactured samples (c) and (f), according to Vickers hardness data. The process occurs in a steam saturated environment between 37 degrees and 120 degrees C. (c) (f) manufactured samples show pore dimension distributions useful to cellular repopulation in living tissues.
用羟基磷灰石制备的磷酸钙人工合成样本，在骨科手术中用作间隔物或填充物，但这些植入物从未在机械应力条件下使用过。水泥的情况也类似。许多作者推测，水泥在体内植入时是一种有用的替代材料。本研究的目的是开发一种孔隙率和结晶度与骨相似的低结晶材料。
将市售羟基磷灰石（HAp）和磷酸二钙（M）粉末与水混合并压实，制成圆柱形样本。该材料在37 - 120摄氏度的饱和蒸汽中进行处理，以获得具有骨传导性的样本。通过X射线粉末衍射（XRD）、维氏硬度测试（HV）、扫描电子显微镜（SEM）和孔隙率评估对样本进行研究。
样本粉末的X射线衍射显示出HAp和M粉末的典型图谱。热处理后，未形成新的晶相，且峰的相对强度没有增加。维氏硬度数据与处理温度没有任何关系。根据特定的热处理，总孔隙率降低了50 - 60%。对含80%HAp - 20%M（c）或50%HAp - 50%M（f）的样本表面进行扫描电子显微镜观察，显示出粉末颗粒的凝聚。
根据维氏硬度数据，在人工合成样本（c）和（f）中，溶解 - 再沉淀过程更为强烈。该过程发生在37摄氏度至120摄氏度的蒸汽饱和环境中。人工合成样本（c）（f）显示出对活组织中细胞再填充有用的孔隙尺寸分布。
