Gypsum Products Most Important MCQs

1 - A rough / Chalky surface of the cast is due to_______________?

---

A. Not waiting for 20 min before pouring

---

B. High speed accelerator

---

C. Air incorporation in the mix

---

D. All of the above

---

All of the above

2 - 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

---

Setting time

3 - ADA specification number of gypsum products are described under____________?

---

A. 1

---

B. 4

---

C. 12

---

D. 25

---

25

4 - As per DNA No. 25, minimum amount of setting expansion required for type V gypsum products_______________?

---

A. 0.05

---

B. 0.1

---

C. 0.15

---

D. 0.2

---

0.1

5 - Balanced stone is dental stone_______________?

---

A. Which undergoes rapid expansion

---

B. In which accelerators or retarders have been added according to need

---

C. In which amount of water of hydration is controlled

---

D. In which the crystals are all of uniform size

---

In which accelerators or retarders have been added according to need

6 - Beta hemihydrate particles absorb______________?

---

A. More water

---

B. Less water

---

C. no water

---

D. None of the above

---

More water

7 - Die is________________?

---

A. Impression of single tooth

---

B. Impression of whole teeth

---

C. Replica of single tooth

---

D. Replica of whole teeth

---

Replica of single tooth

8 - Finer particle size of silica______________?

---

A. Slower the hygroscopic expansion

---

B. Greater the hygroscopic expansion

---

C. Normal setting expansion

---

D. No setting expansion

---

Greater the hygroscopic expansion

9 - Gillmore needle is used for_______________?

---

A. Testing the strength of plaster of paris

---

B. Evaluating the setting time of plaster of pris

---

C. Testing the metal hardness

---

D. Testing the purity of noble metals

---

Evaluating the setting time of plaster of pris

10 - 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

---

The wet strength

11 - Gypsum is used for________________?

---

A. Impressions

---

B. Casts

---

C. Die

---

D. Casts and Dies

---

Casts and Dies

12 - Gypsum product having least expansion_____________?

---

A. Impression plaster

---

B. Model plaster

---

C. Stone plaster

---

D. Die stone

---

Die stone

13 - Impression plaster containing potato starch is called______________?

---

A. Plaster of paris

---

B. Soluble plaster

---

C. Anti – expansion solution

---

D. Die stones

---

Soluble plaster

14 - 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

---

Addition of accelerators and retarders

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

---

A. CaO

---

B. CaCO3

---

C. (CaSO4)2-½H2O

---

D. CaSO4-2H2O

---

(CaSO4)2-½H2O

16 - Modiffiers are added to gypsum mainly to_______________?

---

A. Modify setting time

---

B. Modify setting expansion

---

C. Modify strength

---

D. Decrease the porosity

---

Modify setting time

17 - Most commonly used retarder in gypsum_____________?

---

A. Na2 So4

---

B. Nacl

---

C. Citrales

---

D. K2 So4

---

Citrales

18 - 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

---

Gypsum is slightly soluble in water and the surface of the cast will be eroded

19 - Plaster mix____________?

---

A. Rapid spatulation results in decreased setting time

---

B. 2% potassium sulphate is accelerator

---

C. Citrates are retarders

---

D. All of the above

---

All of the above

20 - Plaster of paris _____________?

---

A. Is wet calcined hemihydrate

---

B. Has porous and irregular crystals

---

C. Is a – hamihydrate

---

D. Has a W / P of 0.2

---

Has porous and irregular crystals

21 - Plaster of paris is mixed in________________?

---

A. Plastic bowl

---

B. Rubber bowl

---

C. Glass bowl

---

D. Metal bowl

---

Rubber bowl

22 - Powders of dental plaster and dental stone differ mainly in____________?

---

A. Solubility

---

B. Shelf life

---

C. Chemical formula

---

D. Particle porosity

---

Particle porosity

23 - Setting of POP is result of______________?

---

A. Difference in solubility of CaSo4 ½ H2O + CaSO4+ 2H2O

---

B. Reaction between CaSO4+ 2H2O and water

---

C. Nucleation and growth of CaSo4 ½ H2O crystals

---

D. Reaction between hemihydrate and hihydrate

---

Difference in solubility of CaSo4 ½ H2O + CaSO4+ 2H2O

24 - The function of 2% potassium sulphate in a gypsum product is_____________?

---

A. To regulate the setting expansion

---

B. Regulate setting time

---

C. Acts as retarder

---

D. None

---

Regulate setting time

25 - The hygroscopic technique is associated with______________?

---

A. Investment

---

B. Hydrocolloids

---

C. Amalgam

---

D. Silicate

---

Investment

26 - The main difference between dental stone and dental plaster is______________?

---

A. Chemical composition

---

B. Self life

---

C. Sharpe and size of particles

---

D. Solubility in water

---

Sharpe and size of particles

27 - The main ingredient in dental plaster in_______________?

---

A. Calcium sulphate hemihydrate

---

B. Calcium phosphate

---

C. Calcium anhydrate

---

D. Calcium sulphate dihydrate

---

Calcium sulphate hemihydrate

28 - The most commonly used accelerator in gypsum product is___________________?

---

A. Sodium fluoride

---

B. Potassium fluoride

---

C. Potassium sulfate

---

D. Aluminium sulfate

---

Potassium sulfate

29 - The product, which is obtained by calcining gypsum under steam pressure at 120-130°C or by dehydrating gypsum in the presence of sodium succinate is_______________?

---

A. Alpha – hemihydrates

---

B. Beta – hemihydrates

---

C. Calcium sulphate dihydrate

---

D. Orthorhombic anhydrate

---

Alpha – hemihydrates

30 - The setting expansion of gypsum products can be reduced by________________?

---

A. Increased spatulation

---

B. Adding potassium sulfate

---

C. Less water powder ratio

---

D. Allowing setting under water

---

Adding potassium sulfate

31 - The strength of gypsum prouducts is generally expressed in terms of______________?

---

A. Tensile strength

---

B. Wet strength

---

C. Green strength

---

D. compressive strength

---

compressive strength

32 - The strength of the gypsum specimen when the water in excess of that required for the hydrate of the hemihydrate is left in the specimen is called____________?

---

A. Dry strength

---

B. Green strength

---

C. Water strength

---

D. Compressive strength

---

Green strength

33 - 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

---

They are more irregular in shape and porous

34 - Type I gypsum product is also called_______________?

---

A. Impression plaster

---

B. Class I stone / Hydrocal

---

C. Class II stone/Densite

---

D. Model plaster

---

Impression plaster

35 - Type III Dental gypsum is__________________?

---

A. Class II stone

---

B. Densite

---

C. Class I stone or hydrocal

---

D. Model or lab plaster

---

Class I stone or hydrocal

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

---

A. 18.6ml

---

B. 22.2ml

---

C. 30.4ml

---

D. 45.3ml

---

18.6ml

37 - Water powder ratio of dental stone and plaster is respectively_________________?

---

A. 0.28 and 0.6

---

B. 0.6 and 0.28

---

C. 0.6 and 3.2

---

D. 0.28 and 0.98

---

0.28 and 0.6

38 - Which is gypsum product_______________?

---

A. Stone

---

B. Plaster

---

C. Investment

---

D. All of the above

---

All of the above

39 - White gold alloy predominantly is______________?

---

A. Gold added with palladium

---

B. Gold added with calcium

---

C. Gold with much of chromium

---

D. Gold with silver

---

Gold added with palladium

Pages