411. In plaster of paris the setting time is primarily altered by_________________?
A. Altering P / L Ratio
B. Altering temperature of mixing water
C. Speed and length of hand spatulation
D. Addition of accelerators and retarders
412. Which is gypsum product_______________?
D. All of the above
413. The most commonly used accelerator in gypsum product is___________________?
A. Sodium fluoride
B. Potassium fluoride
C. Potassium sulfate
D. Aluminium sulfate
414. The hygroscopic technique is associated with______________?
415. 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
416. The main ingredient in dental plaster in_______________?
A. Calcium sulphate hemihydrate
B. Calcium phosphate
C. Calcium anhydrate
D. Calcium sulphate dihydrate
417. Die is________________?
A. Impression of single tooth
B. Impression of whole teeth
C. Replica of single tooth
D. Replica of whole teeth
418. Plaster of paris is mixed in________________?
A. Plastic bowl
B. Rubber bowl
C. Glass bowl
D. Metal bowl
419. Water of reaction needed to react completely with 100 g of calcium sulphate hemihydrates to convert it to calcium sulphate dihydrate______________?
420. Green strength with reference to plaster means_____________?
A. Dry strength
B. Compressive strength
C. Strength of dental stone due to green colour
D. The wet strength