Question: The most commonly used accelerator in gypsum product is___________________?

• 1. Sodium fluoride
• 2. Potassium fluoride
• 3. Potassium sulfate
• 4. Aluminium sulfate

Question: The hygroscopic technique is associated with______________?

• 1. Investment
• 2. Hydrocolloids
• 3. Amalgam
• 4. Silicate

Question: Accelerators and retarders are used with gypsum products mainly to control_______________?

• 1. Setting time
• 2. Setting expansion
• 3. Hardness of the set product
• 4. None of the above

Question: The main ingredient in dental plaster in_______________?

• 1. Calcium sulphate hemihydrate
• 2. Calcium phosphate
• 3. Calcium anhydrate
• 4. Calcium sulphate dihydrate

Question: Die is________________?

• 1. Impression of single tooth
• 2. Impression of whole teeth
• 3. Replica of single tooth
• 4. Replica of whole teeth

Question: Plaster of paris is mixed in________________?

• 1. Plastic bowl
• 2. Rubber bowl
• 3. Glass bowl
• 4. Metal bowl

Question: Water of reaction needed to react completely with 100 g of calcium sulphate hemihydrates to convert it to calcium sulphate dihydrate______________?

• 1. 18.6ml
• 2. 22.2ml
• 3. 30.4ml
• 4. 45.3ml

Question: Green strength with reference to plaster means_____________?

• 1. Dry strength
• 2. Compressive strength
• 3. Strength of dental stone due to green colour
• 4. The wet strength

Question: Water powder ratio of dental stone and plaster is respectively_________________?

• 1. 0.28 and 0.6
• 2. 0.6 and 0.28
• 3. 0.6 and 3.2
• 4. 0.28 and 0.98

Question: Model plaster (white) used to cast study models before mixing with water, is largely composed of____________?

• 1. CaO
• 2. CaCO3
• 3. (CaSO4)2-½H2O
• 4. CaSO4-2H2O