| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a plaster bonding investment material for dental casing with which the expansion of plaster in hardening is terminated in an early period of time and the occurrence of cracking in a completed casting mold is substantially prevented. SOLUTION: The average grain size of the plaster of the plaster bonding investment material for dental casing, in which the plaster used as the casing mold for dental casting is used as a binder and silica or its isomer as a heat resisting material, is >=3 to <=10μm or <=15μm and the ratio of the particles of >=50μm in grain size in the entire part of the plaster is <=10% and further, a water-reducing agent is added to the plaster bonding investment material for dental casting.</p> |
