Initial solubility and durability of polymeric calcium phosphate cements

四个实验和两个商业磷酸钙牙科水泥的机械强度和体外耐久性进行了评估。用X射线衍射分析研究了这些磷酸钙骨水泥中羟基磷灰石的形成过程，并讨论了它们与机械强度的关系。由中、细磷酸四钙粉末和聚（甲基乙烯基醚-马来酸）制备的可形成羟基磷灰石的聚合磷酸钙骨水泥的抗压强度低于由聚（丙烯酸）制备的磷酸四钙骨水泥和不形成羟基磷灰石的商业α-磷酸三钙骨水泥，而抗折强度高于由聚（丙烯酸）制备的磷酸四钙骨水泥。羟基磷灰石的形成似乎对应于降低基于磷酸四钙和聚（甲基乙烯基醚-马来酸）的水泥的抗压强度，而在基于磷酸四钙和聚（丙烯酸）的水泥的情况下，没有观察到羟基磷灰石的形成和抗压强度之间的关系。使用精细研磨的磷酸四钙粉末制备的羟基磷灰石形成聚合物水泥显示出增强的强度，甚至在长时间浸泡在水中之后，与衍生自大尺寸磷酸四钙的类似水泥相比。两种实验性聚合磷酸钙骨水泥的初始溶解度似乎低于使用有机酸制备的商业磷酸钙骨水泥。

Mechanical strength and in vitro durability of four experimental and two commercial calcium phosphate dental cements were assessed. Hydroxyapatite formation processes in these calcium phosphate cements were also examined by means of x-ray diffraction analysis and their relationship with mechanical strength was discussed. The hydroxyapatite-forming polymeric calcium phosphate cements prepared from medium and fine tetracalcium phosphate powder and poly (methyl vinyl ether-maleic acid) showed lower compressive strength and higher flexural strength than the teracalcium phosphate cement prepared using poly (acrylic acid) and non hydroxyapatite-forming commercial α-tricalcium phosphate cements. The hydroxyapatite formation seemed to correspond to lowering in compressive strength of the cements based on tetracalcium phosphate and poly (methyl vinyl ether-maleic acid), while, in the case of the cement based on tetracalcium phosphate and poly (acrylic acid), no relationship was observed between the hydroxyapatite formation and the compressive strength. The hydroxyapatite-forming polymeric cements prepared using finely ground tetracalcium phosphate powder showed enhanced strength, even after prolonged immersion in water, compared to similar cements derived from the large sized tetracalcium phosphate. Initial solubility of both the experimental polymeric calcium phosphate cements seemed to be lower than that of the commercial calcium phosphate cements, which were prepared using organic acids.