Medical MCQs

5099 MCQs  (Page 87 of 510)

Type III Dental gypsum is__________________?
A. Class ii stone
B. Densite
C. Class i stone or hydrocal
D. Model or lab plaster
Beta hemihydrate particles absorb______________?
A. More water
B. Less water
C. No water
D. None of the above
Accelerators and retarders are used with gypsum products mainly to control_______________?
A. Setting time
B. Setting expansion
C. Hardness of the set product
D. None of the above
The most commonly used accelerator in gypsum product is___________________?
A. Sodium fluoride
B. Potassium fluoride
C. Potassium sulfate
D. Aluminium sulfate
Which is gypsum product_______________?
A. Stone
B. Plaster
C. Investment
D. All of the above
The β (Beta) hemihydrate of gypsum requires more water to float its powder particles because______________?
A. They are more regular in shape and dense
B. They are more regular in shape and highly porous
C. They are more irregular in shape and porous
D. They are more dense and prismatic in shape
Placing cast under tap water is to be avoided as______________?
A. H2o interferes with hygroscopic expansion
B. H2o inhibits polymerization of dental resin
C. H2o interferes with crystallization of dihydrate
D. Gypsum is slightly soluble in water and the surface of the cast will be eroded
Modiffiers are added to gypsum mainly to_______________?
A. Modify setting time
B. Modify setting expansion
C. Modify strength
D. Decrease the porosity