| 摘要 |
PURPOSE:To simultaneously satisfy mechanical strength, durability and feeling of transparency, by partially replacing a calcium component of crystallized glass of calcium phosphate type with magnesium to give a specific composition. CONSTITUTION:The crystallized glass for dental material contains 40-75mol.% calculated as P2O5 of phosphorus oxide, 20-50mol.% calculated as CaO of calcium oxide and 2-20mol.% calculated as MgO of magnesium oxide. Further the glass may be optionally blended with 1-15mol.% calculated as Al2O3 of Al oxide, 1-15mol.% calculated as Ce2O3 of Ce oxide and 1-15mol.% calculated as La2O3 of La oxide. In the glass, when P2O5 is <40mol.%, strength and transparency are low and when P2O5 exceeds 75mol.%, durability is low. When CaO is <20mol.%, durability is low and when CaO exceeds 50mol.%, strength and transparency are low. When MgO is <20mol.%, durability is low and when MgO exceeds 20mol.%, the glass becomes opaque.
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