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Dental Materials
Chapter 9- Gypsum Materials
Question | Answer |
---|---|
The desirable strength of gypsum materials is _______ related to the amount if water used. A. directly B. Indirectly C. not D. partially | A. directly |
For gypsum products, a suitable accelerator and retarder, respectively, would be: A. ethyl alcohol and oleic acid B. oleic acid and glycerin C. borax and potassium sulfate D. potassium sulfate and borax | D. potassium sulfate and borax |
The gypsum material known as " high-strength stone" may also be referred to as: A. plaster B. dental stone C. type III stone D. improved stone | D. improved stone |
The final setting time for gypsum products typically is: A. 10-30 min B. 30-45 min C. 45-90 min D. 90-120 min | B. 30-45 min |
To make a correct mix for dental stone when using 50 g of powder, the amount of water would be approximately: A. 10-12 ml B. 14-15 ml C. 28-30 ml D. 45-50 ml | B. 14-15 ml |
At a previous appointment, the orthodontist took impressions of the maxillary and mandibular arches. The replicas made from each impression to discuss the treatment plan are termed: A. casts B. dies C. study models D. molds | C. study models |
Decreasing the setting time of a dental material results in a product that: A. will set faster B. will set slower C. does not effect the setting time D. enhances the properties | A. will set faster |
The weakest gypsum product is: A. improved stone B. dental stone C. plaster D. die stone | C. plaster |
When excess water is not present in a gypsum product, it is known as the: A. wet strength B. dry strength C. initial setting time D. surface strength | B. dry strength |
The best way to mix gypsum products is to: A. "eyeball" the amount of powder added to water B. add water to the powder C. add powder to the water D. add powder and water to bowl simultaneously | C. add powder to the water |
A practical, easy method to determine final setting time in a dental office would be: A. set a timer for 20 min B. observe the change from wet to dry strength C. watch for the loss of gloss D. attempt to penetrate the material with the metal spatula | D. attempt to penetrate the material with the metal spatula |
When the setting time of a dental material is increased, which of the following is true? A. the material sets slower B. the material sets faster C. the setting reaction does not change D. the setting reaction is increased | A. the material sets slower |