Fundamental Studies on Ammonia-free Phosphate-bonded Binder for Dental Investments

Abstract

In order to develop an ammonia-free phosphate-bonded investment , Mg(H2PO4)2•E nH2O and MgO were used as a binder . The ratio (wt%) of MgO to Mg(H2PO4)2•nH20 was designed from 3 to 0.5. Setting time and compressive strength were examined to determine a suitable distribution. A mixture with the ratio of 1 .0 and 1.2 showed excellent properties as the binder. The setting time became shorter and compressive strength became lower as the ratio increased. X-ray diffraction appeared MgHPO 4•E3H20 after setting and Mg21)20, after heated at 800•Ž. These results suggested that Mg (H2PO4)2•nH20 can be applied for dental investments .