8451. Etching depth after 30 sec for orthodontic bracket with orthophosphoric acid is_________________?
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A. 50 um 110 um

B. 10 um 20 um

C. 3 um 9 um

D. 200 um 250 um

8452. The greatest stress which may be produced in a material such that stress is directly proportional to the strain is know as_____________?
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A. The yield strength

B. The proportional limit

C. The elastic limit

D. Modulus of elasticity

8453. Ideal requirement of metal ceramic casting____________?
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A. Matching of coefficients of thermal expansion of ceramics and alloy

B. All of the above

C. Bonding between ceramic and alloy

D. Low fusing ceramic and high fusing alloys

8454. The function of the coupling agent in a restorative resin is to allow______________?
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A. Bonding between filler crystals

B. Adhesion of resin particles

C. Bonding between tooth and resin

D. Bonding between filler and resin

8455. Which of the following provide opacity to composite ?
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A. None of the above

B. TEGDMA

C. BIS-GMA

D. Ti02
8456. The simplest alloy is a_______________?
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A. Ternary alloy

B. Solid solution

C. Peritectic allowy

D. Eutectic alloy

8457. The particle size in microfilled composites is_____________?
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A. 0.01 to 0.1 microns

B. 0.05 to 0.04mm

C. 0.3 to 0.4mm

D. 0.5 to 1.0 microns

8458. Porosity of denture base is due to_______________?
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A. Inadequate pressure

B. Curing at 160F for 9 hrs

C. All of the above

D. Packing at dough stage

8459. Which of the following hardness test is a micro hardness test ?
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A. Rockwell

B. Knoop

C. Shore-A

D. Brinnel

8460. Dentin conditioner has the following function______________?
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A. Removes smear layer

B. Forms a thin resin layer over exposed collagen fibrils

C. Helps in bonding with composite

D. Increases surface energy of dentin

8461. What is the disadvantage of using composites as restorative material ?
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A. Decreased wear resistance

B. None of the above

C. Increased thermal conductivity

D. Decreased thermal conductivity

8462. Which of the following absorbs maximum amount of water ?
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A. Macrofilled resin

B. Microfilled resin

C. Hybrid

D. Light cure activated

8463. The inlay wax most commonly used for direct technique_____________________?
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A. Type 1

B. Type 3

C. Type 4

D. Type 2

8464. No trail closure is necessary with which one of the technique during denture fabrication_____________?
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A. Compression moulding technique

B. Fluid resin technique

C. Light cured technique

D. Injection moulding technique
8465. Acrylic (cold cure)______________?
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A. Softens at 100C

B. Melts at 100C

C. Produces heat during polymerization

D. Still requires heat for polymerization

8466. KHN of enamel is close to______________?
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A. Pure gold

B. Amalgam

C. Composite

D. Prcelain
8467. Brinnel hardness number of a dental gold alloy is directly proportional to its______________?
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A. Tensile strength

B. Modulus of resilience

C. Elongation

D. Modulus of elasticity

8468. Use of dimethyl-P-toluidine is indicated for_______________?
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A. Chemical polymerization

B. To inhibit the action of benzoyl peroxide

C. Thermal polymerization of acrylic

D. Retarding the polymerization reaction

8469. The forces that hold atoms together are called_____________?
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A. Secondary forces

B. Ionic forces

C. Cohesive forces

D. Primary forces

8470. Stress in defined as_______________?
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A. A deformation resulting from an applied load

B. An external force opposing an applied load

C. An applied load or force

D. An internal force opposing an applied load
8471. To prevent porosity in self-cure acrylic resin, curing should be carried in______________?
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A. Under vacuum pressure

B. Under tap water

C. Hot water

D. Cold water

8472. Flow of a material refers to_______________?
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A. Dimensional change of the material during settings

B. The homogencity of gypsum products

C. Continued change of the material under a given load

D. The consistency of material when mixing

8473. The main form of iron carbide found in 18-8 steel________________?
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A. Ferrite

B. Martensite

C. Austenite

D. Pearlite

8474. The purity of gold is expressed in________________?
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A. Gram

B. Fineness

C. Carats

D. Percentage

8475. Along with polymerisation shrinkage, one of the major disadvantages of polymethyl methacrylate as denture base resin are its poor_____________?
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A. Thermal properties

B. Esthetic properties

C. Biological properties

D. Mechanical properties

8476. The commonly used laser for curing composite resin is______________?
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A. Nd:YAG

B. CO2

C. ER:YAG

D. Argon
8477. Residual monomer content of chemically activated resins is______________?
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A. 0.2% to 0.5%

B. 0.3% to 0.5%

C. 2% to 5%

D. 2% to 5%
8478. Silica sol__________________?
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A. Acts as a retarder in the silica bonded investments

B. Increase the strength and the setting expansion of the phosphate-bonded investment

C. Acts as a refractory in the Silica bonded investments

D. Is applied to the walls of the investment to produce hygroscopic expansion

8479. Which of the following inhibitor accelerator system uses light activation composite ?
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A. Diketone-amine

B. Peroxide-amine

C. Organic acid-metal oxide

D. Organic acid-peroxide

8480. The most important disadvantage of acrylic denture base is_______________?
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A. Tooth breakage

B. Water absorption

C. Shrinkage

D. porosity

8481. Cold cure acrylic expand in water by___________?
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A. 1% by volume 0.23% by weight

B. None of the above

C. 0.1% by volume 0.23% by weight

D. 10% by volume 0.23% by weight

8482. In processing methyl methacrylate, the resin may show porosity if the flask is placed too soon porosity most likely occur_____________?
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A. On the denture surface

B. Throughout the denture

C. In the thickest part

D. Near the borders

8483. Coefficient of thermal expansion of which of following is most similar to that of tooth ?
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A. Gold foil

B. Acrylic resin

C. Silicate cement

D. Gold inlay

8484. Setting expansion is advantageous in__________________?
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A. Investment

B. Dies

C. Casts

D. Models

8485. Compressive stress is computed by dividing the external force by the_______________?
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A. Length of the test specimen beneath the force

B. Strain of the test specimen per unit length

C. Area of the test specimen upon which the weight rests

D. Elasticity of the test specimen in strain

8486. VLC resins are also called as______________?
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A. Microwave-activated resins

B. Heat activated resins

C. Light activated resins

D. Tertiary amine-activated resins

8487. If curing occurs at temperature more than 100C porosity results in which area of denture______________?
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A. Thin area of flanges

B. Porosity is uniformly distributed

C. Thin Palatal area

D. Hard thick central area
8488. Brazilian test is used to determine the ultimates tensile strength of_________________?
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A. Malleable materials

B. Ductile materials

C. Brittle materials

D. Flexible materials

8489. The Knoop Hardness Number of Microfilled composite Restorative material ranges from____________?
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A. 40 48 KHN

B. 25 35 KHN

C. 50 60 KHN

D. 15 20 KHN

8490. Deformation that is recovered upon removal of an externally applied force or pressure is known as_____________?
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A. Flexural strain

B. Plastic strain

C. Youngs modulus

D. Elastic strain
8491. The chemical used to etch enamel is_______________?
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A. Eugenol

B. Zinc oxide

C. Phosphoric acid

D. Methyl methacrylate

8492. Cross linking in denture base resin is contributed by_____________?
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A. Glycol dimetharylate

B. Benzoyl peroxide

C. N-para toluidine

D. Methyl methacrylate

8493. A restorative material which has a high proportional limit, compared with one with a lower proportional limit would have________________?
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A. More resistance to permanent deformation

B. Greater toughness

C. A higher modulus of elasticity

D. A higher modulus of elasticity

E. Greater ductility

8494. Which of the following is NOT true of polymethyl methacrylate ?
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A. Knoop hardness number 18 to 20

B. Density of 1.13 g/cm3

C. Tensile strength of 60 MPa

D. Modulus of elasticity of 3.4 GPa
8495. In self-cure acrylic resin, activator is_____________?
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A. Benzoyl peroxide

B. Quaternary ammonium compound

C. Toluidine

D. Tertiary amine
8496. About polymerization shrinkage of composite all are true, except______________?
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A. Acid etching and priming will decrease polymerization shrinkage

B. Polymerization shrinkage is greater if bonded surface area is lesser than unbounded surface area

C. Microleakage can occur because of polymerization shrinkage

D. Polymerization shrinkage is high if within the enamel margins

8497. A material behaves in certain ways above and below the proportional limit on a stress strin curve, which of the following is correct______________?
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A. Either A or B

B. Above the proportional limit a material function in a plastic manner, while below the proportional limit it behaves as an elastic

C. Neither A or B

D. Above the proportional limit a material functions in an elastic manner, while below the proportional limit it behaves as an plastic

8498. When solid gets wet completely contact angle is______________?
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A. 0 90

B. >90

C. 0

D. 90

8499. Ultimate tensile strength refers to_________________?
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A. Stress after rupture

B. Longitudinal compressive strength

C. Stress before rupture

D. Horizontal compressive strength

8500. The modulus of elasticity is defined as_______________?
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A. The strain at the proportional limit

B. The stress at the proportional limit

C. None of the above

D. The stress/strain ratio within the proportional limit