IPS Empress^<【○!R】>用鋳型埋没材の硬化・熱膨張および表面性状 [in Japanese] Setting-Thermal Expansion and Surface Texture of the Special Investment Material for IPS Empress^<【○!R】> [in Japanese]
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IPS Empress<SUP>®</SUP> is a system for producing all-ceramic dental restorations by a heat-press molding method.<BR>The dimension and the inside surface texture of the mold due to special phosphate bonded investments directly influence the fit of restorations. Therefore, the L/P ratio and the dilution ratio of the special liquid containing colloidal silica are indicated for each type of restoration. The purposes of this study were to measure the setting and thermal expansion of two types of investment mixed according to indicated conditions and to observe the surface texture of the mold of investment by scanning electron microscopy, because the irregularities of ceramic surface are occasionally found after molding.<BR>Results: 1. The setting and the thermal expansion of investment for the staining technique had a tendency to become bigger in proportion to the increase of the special liquid. 2. The total value of setting and thermal expansion of the investment for the staining technique was within the range of 1.36-1.53%, and the thermal expansion was 80% of the total value. While the value of the investment for the layering technique was 1.96%, and there was no significant difference between the two values of setting and thermal expansion. 3. There was no significant difference between the two preheating methods. 4. The irregularities existing on the ceramic surface after pressing was due to the porous surface of the investment mold.
- Nihon Hotetsu Shika Gakkai Zasshi
Nihon Hotetsu Shika Gakkai Zasshi 41(2), 286-291, 1997-04-01
Japan Prosthodontic Society