Investment material and mold for dental use and burnout thereof
US5373891A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 6, 1992 |
| Grant date | Dec 20, 1994 |
| Priority date | — |
| Expiry date | Apr 6, 2012 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61K6/858
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
Dental investment materials for providing inexpensive dental investments which are free from the occurrence of cracks, crevices or breakage and can greatly reduce the metal casting time, dental casting molds using the same and a process for burning them. The dental investment material contains as the major components a calcined gypsum powder, a cristobalite powder and a quartz powder and additionally contains a gas permeability improving additive. In the dental investment prepared using such dental investment material, the thermal expansion can be dispersed and the steam pressure generated can be released effectively during calcination and burning.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.