2551. Cobalt-Chrominum alloys contains_______________?
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A. 30% cobalt and 60% chrominum

B. 60% cobalt and 30% chrominum

C. 20% gold

D. 1% palladium

2552. Most commonly used retarder in gypsum_____________?
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A. Nacl

B. Na2 So4

C. Citrales

D. K<sub>2</sub> So<sub>4</sub>

2553. Agar is prepared from_______________________?
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A. Chemicals

B. Chick cells

C. Bullock heart

D. Sea weed
2554. The advantage of ZOE impression paste_______________?
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A. Does not require special trays

B. Has dimensional stability

C. Is easy manipulation

D. Does not adhere to tissues

2555. Trisodium phosphate in alginate acts are_______________?
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A. Retarder

B. Reactor

C. Accelerator

D. Plasticizer

2556. Wash or corrective impression is done by______________?
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A. Impression paste

B. Rubber base impression material

C. Alginate

D. Impression plaster

2557. Name the accelerator used in Zinc oxide eugenol paste______________?
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A. Olive oil

B. Zinc acetate

C. Linseed oil

D. All of these

2558. Waxes are used for_______________?
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A. Corrective impressions

B. Impression of single tooth

C. None of the above

D. Primary impression

2559. Stages of annealing in order_________________?
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A. Melting point, grain growth, Recrystallization

B. Recrystallization recovery, grain growth

C. Grain Growth Recrystallization recovery

D. Recovery recrystallization grain growth
2560. Glossy smooth margins of a casting are due to_____________?
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A. Incomplete wax elimination

B. Incomplete gas elimination

C. Shrinkage of alloy on cooling

D. Investment breakdown

2563. Syringe material is______________?
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A. High viscosity elastomer

B. Medium viscosity elastomer

C. Low viscosity elastomer

D. Medium & low viscosity elastomer

2564. Powders of dental plaster and dental stone differ mainly in____________?
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A. Particle porosity

B. Solubility

C. Chemical formula

D. Shelf life

2566. Titanium casting is done_____________?
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A. Under air pressure in nitrogen atmosphere

B. In specially fabricated aluminium vanadium

C. Using CAD-CAM technique

D. Under vacuum in argon atmosphere
2567. Impression compound base_____________?
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A. Crystalline structure

B. High fusion temperature

C. Formation of cross linkage with heating

D. Low thermal conductivity
2568. Asbestos liner is used in a casting ring to________________?
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A. Facilitate venting of the mold

B. Permit expansion of the world

C. All of the above

D. Retard the heating of the investment

2569. The impression with the least dimensional change upon disinfection is_______________?
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A. Polysulphide

B. Polyether

C. Agar-agar

D. Addition poly silicone
2571. Fins and spines on the casting is seen due to_______________?
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A. Rapid heating me

B. Water film contamination

C. Prolonged heating:

D. Too high pressure during casting

2573. Alginates are_____________?
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A. Colloid

B. Gel

C. Sol

D. Hydrocolloid
2574. Tublulence of molten gold is due to _____________?
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A. A and B

B. None of the above

C. Impurities in gold

D. Improper venting

2575. Linear contraction of elostomeric impression with passage of time is highest in______________?
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A. Polysulphide

B. Addition silicone

C. Condensation silicone

D. Polyetner

2577. Masterial causing minimum tissue distortion is______________?
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A. Impression plaster

B. Silicone

C. Zinc oxide eugenol paster

D. Polysulphide

2578. Gypsum is used for________________?
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A. Impressions

B. Casts

C. Die

D. Casts and Dies
2579. Addition of large amounts of platinum to a casting gold alloy will________________?
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A. Decrease its strength and ability to be hardened

B. Increase its fusion temperature

C. Redden the alloy

D. Decrease its tarnish resistance

2580. The impression material used to record the prepared areas on abutment teeth is______________?
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A. Low viscosity elastomeric impression material

B. None of the above

C. High viscosity elastomeric impression material

D. Medium viscosity elastomeric impression material

2581. Dimensional stability of elastomeric impression material can be given in descending order as_____________?
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A. Addition silicone> Condensation silicone > Polysulphide > polyether

B. Polysulphide > polyether > Condensation silicone > Addition silicone

C. polyether > Condensation silicone > Polysulphide > Addition silicone

D. Addition silicone > polyether > Polysulphide > Condensation silicone
2582. Localised shrinkage porosity is seen when there________________?
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A. Thin sprue

B. No reservoir

C. Investment heated strongly

D. Inadequate air discharge

2583. Which zone is the hottest and efficient burning zone of the flame used for casting ?
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A. Reducing zone

B. Oxidizing zone

C. None of the above

D. Combustion zone

2584. Best material for duplicating cast is_______________?
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A. Agar-agar

B. Zinc oxide eugenol

C. Plaster of paris

D. Alginate

2585. K2SO4 in agar-agar is for_______________?
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A. Give dimensional stability

B. Accelerating the setting stage of gypsum

C. Increase strength

D. None of the above

2587. Alginates are made dust free by adding______________?
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A. Glycol

B. Glutamic acid

C. alcohol

D. Glyecrol
2588. The sprue in wax pattern should be placed________________?
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A. At obtuse angle

B. At right angle

C. At 45C angle

D. It depend upon type of wax pattern

2589. Hysteresis in a hydrocolloid gel is______________?
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A. All of the above

B. Temperature lag between gelation and liquefaction temperature

C. Moisture absorption

D. Phenomenon of conversion of gel into sol

2591. Brush heap structure is found in______________?
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A. Agar

B. Polyether

C. Condensation silicone

D. Zinc oxide impression material

2592. Inlay wax is used to_______________?
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A. Invest inlay patterns

B. Make inlay wax patterns

C. Box models

D. Temporarily cement inlays:

2594. Nickel is added to wrought gold alloys as______________?
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A. Scavenger

B. Hardener

C. Whitens the alloy

D. Strengtherner
2595. The relative hardness of elastomere is determined using________________?
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A. Rockwell tester

B. Shore durometer

C. Barcol indenter

D. Knoop pyramid

2596. Mouth temperature waxes are_______________?
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A. None of the above

B. Green stick wax

C. Modeling wax

D. Iowa wax
2597. The purity of gold is expressed in________________?
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A. Gram

B. Percentage

C. Fineness

D. Carats

2598. Gelation temparature of agar is between________________?
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A. 27C to 33C

B. 55C to 60C

C. 20C to 25C

D. 37C to 50C
2599. Rinsing of the impression is important to________________?
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A. Remove excess impression material

B. Accelerate the setting

C. Hydrate the impression

D. Remove saliva
2600. Which of the following is used as surface hardener in Impression material ?
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A. 2% Potassium sulfate

B. 0.2% Potassium sulfate

C. 4% Potassium sulfate

D. 2% sodium sulfate