dental materials MCQs – Page 19

Practise focused dental materials questions with marked answers for exam preparation and subject revision.

dental materials Mcqs
361. Dendrites in cst alloys form by mechanism of_________________?
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A. Constitutional supergriting

B. Constitutional superconductivity

C. Constitutional supercooling

D. Constitutional supergraining

362. Which of the following component acts as an accelerator in ZOE impression paste ?
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A. Zinc Sulphate & Zinc chloride

B. Zinc Sulphate & Eugenol

C. Glycerin

D. Zinc chloride & Eugenol

363. Fins and spines on the casting is seen due to_______________?
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A. Too high pressure during casting

B. Prolonged heating:

C. Water film contamination

D. Rapid heating me
364. Gases dissolved in molten metals are liberated when cooled giving rise to________________?
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A. Gas inclusion porosity

B. Suckback porosity

C. Microporosity

D. Localized shrinkage porosity

365. K2SO4 in agar-agar is for_______________?
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A. Increase strength

B. Accelerating the setting stage of gypsum

C. Give dimensional stability

D. None of the above

366. Plaster mix____________?
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A. All of the above

B. Rapid spatulation results in decreased setting time

C. Citrates are retarders

D. 2% potassium sulphate is accelerator

367. Which of the following is correct glass transition temperature of Impression compound ?
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A. 100C

B. 43.5C

C. 39C

D. 65C

368. Best material for duplicating cast is_______________?
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A. Plaster of paris

B. Alginate

C. Agar-agar

D. Zinc oxide eugenol

369. Addition of large amounts of platinum to a casting gold alloy will________________?
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A. Redden the alloy

B. Decrease its tarnish resistance

C. Increase its fusion temperature

D. Decrease its strength and ability to be hardened

370. Alginates are_____________?
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A. Colloid

B. Hydrocolloid

C. Gel

D. Sol

371. Softening heat treatment of alloy increases_________________?
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A. Ductility

B. Hardness

C. Tensile strength

D. Proportional limit

372. Which is the use of boxing an impression______________?
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A. All of the above

B. Ease of construction of denture

C. Ease of pouring an impression

D. Preserving the sulci

373. Final product in alginate is________________?
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A. Potassium alginate

B. Trisodium phosphate

C. Calcium alginate

D. Sodium alginate

374. By product of condensation reaction between silicone base and alkyl silicate in presence of tin octate_______________?
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A. Propanolol

B. Acetate

C. Ethyl alcohol

D. Glycol

375. Gillmore needle is used for_______________?
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A. Evaluating the setting time of plaster of pris

B. Testing the purity of noble metals

C. Testing the strength of plaster of paris

D. Testing the metal hardness

376. Which of the following impression material requires a hardener ?
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A. Impression compound

B. Alginate

C. Agar

D. Elastomers

377. Gold content of an 18 carat alloy is______________?
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A. 100%

B. 75%

C. 50%

D. 25%

378. The castability of chromium-cobait base metal alloys when compared to gold based noble metal alloys is_______________?
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A. Less

B. Equal

C. More

D. Depends on the alloy type

379. The most commonly used accelerator in gypsum product is___________________?
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A. Potassium fluoride

B. Aluminium sulfate

C. Sodium fluoride

D. Potassium sulfate
380. In reversible hydrocolloid the property by which the transformation from sol to gel and gel to sol is a function of the_____________?
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A. Concentration of potassium sulphate

B. Concentration of filler and plasticizer

C. Percentage composition by weight of water

D. Temperature