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Dental Materials 164
unit 5 PIMA
Question | Answer |
---|---|
Using the amount of water in your mix of dental stone would... | lengthen the setting time produce thiner mix produce weaker cast |
Bypsum products set faster when... | reduce the water/powder ratio |
If chemical shortens the setting time of gypsum it is called... | accelerator |
Potasium sulfate is added to gypsum productto... | Allelerate set and reduce expansion |
A dental stone cast is_____ than plaster cast... | stronger |
In mixing gypsum product it is recomended that... | powder should be sifted into the water |
During setting, a plaster cast will... | expand |
In pouring stone should be added at only one corner of an impression to prevent... | air on water from being trapped on the surface of the cast |
Plaster may be used... 2 | as study models attach models to articulators |
High strength dental stone (class II improved) is used... | to make dies |
Dental stone is | calcuim sulfate hemhydrate |
The heat which is given off during a chemical reaction is termed... | exothermic heat |
______ _____has the lowest water to poeder ratio... | die stone |
The strength and hardness of gypsum madel or cast depends on... | water-powder ratio and porosity of cast |
____, ____, _____ would shorten (decrease) setting time of plaster stone... | use of warm water increasing the rate of spatulation decrease water powder ratio use of accelerators |
TorF? It's desiriable to allow plaster or stone to set for 45-60 minutes before removing the cast from the impression... | True |
TorF? Trapped air in the mix of stone or plaster will appear raised on the model... | False |
Gypsum products should be mixed to a ____ consistensy... | creamy |
TorF? All of the different types of gypsum products have different water powder ratio... | True |
TorF? Moisture is not a consern when storing gypsum products | False |