medical MCQs – Page 133

Practise multiple-choice questions from medical for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

2641. ADA specification number of gypsum products are described under____________?
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A. 4

B. 25

C. 1

D. 12

2642. The base paste of the condensation poly sillicone has a low molecular weight dimethyl siloxane with a terminal-group_______________?
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A. Hydroxyl group

B. Silane group

C. Marcaptan group

D. Virryl group

2643. Rough and irregular surface produced on the impression is because of ?
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A. Air incorporated during mixing

B. Too rapid polymerization

C. Presence of moisture in impression area

D. Improper application of pressure during impression making

2644. The porosity formed due to simultaneous nucleation of solid grains and gas bubbles at the first moment that metal freezes at the mold walls is called__________?
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A. Micro porosity

B. Pinhole porosity

C. Gas inclusion porosity

D. Subsurface porosity
2645. Solder and flux used for joining Elgiloy wires are_____________?
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A. Gold solder and borax flux

B. Silver solder and fluoride flux

C. Silver Solder and borax flux

D. Gold solder and fluoride flux

2646. Suck back porosity in the casting can be eliminated by________________?
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A. Flaring the point of the sprue attachment

B. Increasing the mould metal temperature difference

C. Increasing the flow of molten metal

D. All of the above

2647. Rapid removal of rubber impression with a single firm motion results in____________________?
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A. Reduced contamination by saliva

B. Reduced dimensional instability

C. Improved adhesion of the impression to the tray

D. Minimal permanent deformation
2648. The most mucostatic impression material is_______________?
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A. Free flowing wax

B. Reversible hydrocolloids

C. Thin mix of plaster of paris

D. Zinc oxide eugenol impression paste

2649. Tear strength for impression material is highest for__________?
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A. Addition silicone

B. Alginate

C. Condensation silicone

D. Polysulfide
2650. Two in one stage impression materials include______________?
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A. Zinc Oxide eugenol impression paste

B. Elastomeric impression material

C. Hydrocolloid impression material

D. All of the above

2651. Lenolin is added is ZOE paste to______________?
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A. Decrease flow

B. Increase flow

C. Decrease irritation due to eugenol

D. Accelerate reaction

2652. The rate of tarnish and corrosion of class II cast material having VHN 200 is_______________?
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A. <1%

B. 5 to 10%

C. 0%

D. 2 to 3%

2653. Plaster of paris _____________?
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A. Has porous and irregular crystals

B. Has a W / P of 0.2

C. Is wet calcined hemihydrate

D. Is a hamihydrate

2654. Dimensional stability of hydrocolloid impressions may be achieved by_________________?
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A. Using humidor

B. Using less water powder ratio

C. Storing the impression under water

D. Prolonged manipulation

2655. Trisodium phosphate added to alginate contributes towards_______________?
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A. Initiating the setting reaction

B. Provides gel strength

C. increasing the working time of alginate impression material

D. Acts as an accelerator

2656. Which one of the following impression materials is elastic, sets by a chemical reaction and is catalyzed by chloroplatinic acid_______________?
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A. Poly vinyl siloxane

B. Polyether

C. Condensation silicone

D. Polysulfide

2657. The term ordered hardening heat treatment used in which of the following dental alloys ?
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A. Silver-Palladium

B. Nickel-Titanium

C. Nickel-Chromium

D. Gold-Copper
2658. Which material is the most difficult to remove from the patients mouth ?
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A. Reversible hydrocolloid

B. Impression plaster

C. Silicone impression material

D. Metallic oxide paste
2659. A rough / Chalky surface of the cast is due to_______________?
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A. All of the above

B. Air incorporation in the mix

C. High speed accelerator

D. Not waiting for 20 min before pouring

2660. Gypsum product having least expansion_____________?
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A. Die stone

B. Stone plaster

C. Model plaster

D. Impression plaster