Gypsum seting time
Pouring the impression Only the amount required for two to three impressions should be mixed at a time. The vacuum should not be set too high when mixing.
After this the setting time begins. A micrometer dial evaluated the dimensional change.
Setting time of gypsum plaster
Quality may be affected if other liquids are used, such as water from the trimmer or gypsum hardener liquids. After the gypsum has been soaked for 20 seconds, it can be mixed with a spatula. Liquids with high pH accelerate setting. Statistical analysis The data were subjected to two-way ANOVA, using gypsum factor in two levels IV and V and water factor in three levels tap, mineral and distilled water , totalizing 6 treatments with 10 repetitions each. Impression plaster type 1 is always mixed manually for 30 seconds. Mixing in a vacuum mixer improves the quality of the mixture and saves time. The test was performed on the left specimen face that was in direct contact with the metal matrix, which provided a smooth standardized surface. Mixing water Tap water, which has been allowed to sit at room temperature, can normally be used for mixing. The process continues until all hemihydrate converts to dihydrate. Any residue would have a negative effect on the setting time and expansion of the mixture. In the present study, a 7. The more water in the mix of model; plaster, dental stone, or high-strength dental stone ; the longer the setting time. Manual mixing requires approx. For dental treatment success, gypsum models should copy, as faithfully as possible, the desired structures contained in the mold 2.
Preparation For the best results it is essential that the equipment is clean and free from residue before mixing the gypsum. Pouring the impression should be completed within the working time.
This is called hygroscopic expansion. Manual mixing requires approx.
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