| 摘要 |
PURPOSE:To obtain the title mold material, containing a powdery ingredient consisting of a soluble phosphate and magnesium oxide, powdery ingredient of alumina, zirconia, etc., crystalline quartz, cristobalite and colloidal silica dispersion and hardly causing cracks, etc. CONSTITUTION:The titled mold material containing 5-20wt.% soluble phosphate, 5-20wt.% magnesium oxide and 10-50wt.% one or two or more selected from alumina, zirconia, fused quartz, mullite, spinel and cordierite as powdery ingredients and the remainder of crystalline quartz and cristobalite and further a colloidal silica dispersion as a liquid ingredient. This model material is used for preparing a dental porcelain reparative material, such as porcelain laminate veneer or porcelain inlay, and thermal change ratio can be regulated without causing cracks in the model even by repeated calcination. Strength and durability are improved without any fear of fracture and damage. |
