| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a dental investment capable of giving a molding having an extremely small curing shrinkage, large thermal expansion, high accuracy and small surface roughness by adding a specific inflation imparting material to dental investment containing a refractory material and a binder. SOLUTION: This dental investment consists of the refractory material, the binder and aluminum hypophosphite added as the inflation imparting material. Spherical fine powder of aluminum hypophosphite is preferred as the aluminum hypophosphite, affording improved degrading characteristics and uniform mixing. A mixture of cristobalite and quartz is preferred as the refractory material. Phoshate based compounds are preferred as binders. The compounding ratio of this invention is (0-78 pts.wt.) of cristobalite, (0-78 pts.wt.) of quartz, (20-40 pts.wt.) of plaster and (2-20 pts.wt.) of aluminum hypophosphite based on 100 pts.wt. of the total.</p> |
