dental materials MCQs – Page 14

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

dental materials Mcqs

261. With indirect spruing. Which one of the following porosities can be minimised_______________?
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A. Back pressure porosity

B. Micro porosity

C. Pin hole porosity

D. Localized shrinkage porosity

262. Hysteresis in a hydrocolloid gel is______________?
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A. Phenomenon of conversion of gel into sol

B. Temperature lag between gelation and liquefaction temperature

C. Moisture absorption

D. All of the above

263. The best pickling solution for gypsum bonded investment is_______________?
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A. Hydrochloric acid

B. Phosphoric acid

C. Sulphuric acid

D. Nitric acid

264. Function of carnauba wax_________________?
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A. Increase toughness

B. To provide a smooth and glossy surface

C. Decrease toughness

D. Decrease flow at room temperature

265. Crucible indicated for casting base metal alloys is______________?
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A. High melting plastic crucible

B. Clay crucible

C. Quartz crucible

D. Carbon crucible

266. Stages of annealing in order_________________?
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A. Recrystallization recovery, grain growth

B. Grain Growth Recrystallization recovery

C. Recovery recrystallization grain growth

D. Melting point, grain growth, Recrystallization

267. Linear coefficient of thermal expansion of metal used for metal caramic restoration range from________________?
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A. 11.5-12.510-6/C

B. 13.5-14.510-6/C

C. 10.5-11.510-6/C

D. 16.5-17.510-6/C

268. The impression materials with lowest viscosity is_____________?
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A. Elastomers

B. Plaster of paris

C. Zinc oxide eugenol

D. Agar agar

269. The relative hardness of elastomere is determined using________________?
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A. Knoop pyramid

B. Rockwell tester

C. Barcol indenter

D. Shore durometer

270. Masterial causing minimum tissue distortion is______________?
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A. Impression plaster

B. Zinc oxide eugenol paster

C. Polysulphide

D. Silicone

271. Wax pattern is ideally invested immediately to decrease the dimensional changes caused by_______________?
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A. Water loss

B. Decrease flow

C. Relaxation of the internal stresses

D. Continuous expansion

272. The yield strength of AUstenite (NiTi alloy) is______________?
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A. 240 Mpa

B. 100 Mpa

C. 560 Mpa

D. 700 Mpa

273. 4th state of matter is______________?
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A. Liquid

B. Solid

C. Gas

D. Colloid

274. Which material is the most difficult to remove from the patients mouth ?
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A. Silicone impression material

B. Reversible hydrocolloid

C. Impression plaster

D. Metallic oxide paste

275. Impression compound has which of the following characteristic property ?
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A. Degradation is presence of moisture

B. High flow property

C. Remain distortion free up to 72 hrs. pouring can be safely delayed

D. Low thermal conductivity

276. When making a polysulphide impression for a caste crown, custom trays are usually preferred over stock trays for all of the following reasons except_______________?
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A. Custom trays facilitate uniform contraction of impression material

B. Custom trays require less impression material

C. Impressions made n the custom trays are easier to remove from the mouth

D. Stock trays may be short in the flange area

277. As per DNA No. 25, minimum amount of setting expansion required for type V gypsum products_______________?
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A. 0.2

B. 0.15

C. 0.10

D. 0.05

278. A common electrolyte used for plating copper indirect dies is_______________?
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A. Ionic copper

B. Acidic copper sulfate

C. Copper cynide

D. Silver cyanide

279. Which of the following is not affected by saliva ?
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A. Impression paste

B. Silicon impression material

C. None of the above

D. Impression plaster

280. Perforated impression tray are used for_______________?
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A. Zinc oxide-eugenol

B. Impression compound

C. Alginate

D. Agar-agar

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