Abstract
A hardened cement was obtained by kneading an equimolar powder of tetracalcium phosphate and dicalcium phosphate dihydrate with 40%(w/w) citric acid solution.
Setting time, compressive strength, solubility and disintegration of the cement were measured at a P/L (powder to liquid ratio) =2.0(g/ml) by the methods specified by JIS T-6602.
PH change of its paste was measured by measuring surface pH of the paste dissolved in phosphate buffer solution. The composition of the hardened cement was analyzed by using X-ray diffraction (XRD) of powder.
Following results were obtained;
Setting time was about 2′45″. Compressive strength was about 60.95MPa and after autoclaving, it dropped to 32.12MPa. Solubility and disintegration was about 1.51%. The pH value of the paste was increased from 4.61 to 7.00 with the elapse of time. The results of XRD showed that the main reaction products were hydroxyapatite and calcium carbonate.
