dental materials Mcqs
51. The ability of the base to resist occlusal forces and to support the restoration is affected by_______________?
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A. Tensile strength

B. Youngs modulus

C. Compressive strength

D. Modulus of elasticity

52. Which one of the following is used as filler in composite resins ?
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A. Silicates

B. Zinc particles

C. Quartz

D. Aluminium

54. Subsurface porosity is due to_____________?
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A. Packing past the dough stage

B. Thermal changes

C. Thickness of the resin

D. Lack of temperature

55. The % of free monomer in a heat cured acrylic resin is_______________?
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A. 0.6% to 0.8%

B. 8% to 10%

C. 3% to 5%

D. 0.2% to 0.5%
56. Which one of the following is used as filler in composite resins ?
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A. Aluminium

B. Silicates

C. Zinc particles

D. Quartz
57. Munsell system is used to_________________?
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A. Evaluate brittleness of different alloys

B. Define and measure colour qualitatively

C. Measures different colours quantitatively

D. Define and measure physical properties of gold alloys

58. Most advantageous indication of acid etching is______________?
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A. Decrease coefficient of thermal expansion

B. Decrease porosity in restorative material

C. Decrease micro leakage

D. Decrease polymerization shrinkage

59. Which of the following may result if an excessive amount of monomer is incorporated into an acrylic resin mixture ?
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A. Low impact strength

B. Excessive shrinkage

C. Excessive expansion

D. Excessive brittleness

60. Strain is defined as_____________?
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A. An external force opposing an applied load

B. A deformation resulting from an applied load

C. An applied load or force

D. An internal force opposing an applied load

61. Which of the following is correct________________?
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A. Type I and Type II gold can be heat treated and annealed

B. Type I and IV gold can be heat treated and annealed

C. Type III and Type IV gold can be heat treated and annealed

D. All the type of gold can be heat treated and annealed

62. Macromolecules in Dental Resin is attached by______________?
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A. sonic bonds

B. Vander Walls Forces

C. Covalent bonds

D. Hydrogen Bonds

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

B. Combustion zone

C. Oxidizing zone

D. None of the above

66. One bottle system of adhesive resins_____________?
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A. Contains only primer

B. 4th generation bonding agents

C. Separate etching step not required

D. Separate etching step is still required
67. If resin is packed in sandy stage what will be seen in the processed denture ?
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A. Inhomogeneous colour

B. Increased strength

C. Porosity

D. Distortion

69. Which one of the following is most elastic ?
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A. Nickel-titanium

B. B titanium

C. Chrome-cobalt-nickel

D. a titanium

70. Investment material used for cobalt-chromium alloys is_____________?
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A. Gypsum bonded

B. Silica bonded

C. Phosphate bonded

D. None of the above

71. Localised shrinkage porosity is seen when there________________?
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A. No reservoir

B. Inadequate air discharge

C. Investment heated strongly

D. Thin sprue
73. If resin is packed in sandy stage what will be seen in the processed denture ?
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A. Inhomogeneous colour

B. Distortion

C. Increased strength

D. Porosity
74. Hydroquinone is added to methyl methacrylate monomer_________________?
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A. All of the above

B. To prevent polymerization during storage

C. To initiate release of free radicalls

D. To enable polymerization reaction at room temperature

76. For esthetic areas where high luster is required the restoration used usually______________?
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A. Microfilled resin composites

B. Glass ionomer restoratives

C. Hybrid resin composites

D. Macrofilled resin composites

77. Cleaning of base metal alloy is done by______________?
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A. Cold H2SO4

B. Sand blasting with aluminium oxide

C. Warm HCI

D. Cold HF

78. The imperfection seen on the lingual flange of a lower denture caused by rapid heating during a curing cycle is called_____________?
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A. Micro porosity

B. Localised Shrinkage porosity

C. Gas inclusion porosity

D. Surface porosity

79. In heat cure denture base acrylic resins the monomer is___________?
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A. Methyl ethyl methacrylate

B. Polymethylmethacrylate

C. Methacrylate

D. Ethylmethacrylate

80. Austenite is an alloy of iron of and carbon with the iron in______________?
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A. Gamma form

B. Beta form

C. Alpha form

D. None of the above

83. Which of the following is present in the powder of the acrylic resin______________?
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A. D-methyl paratolouidine

B. Methyl methacrylate

C. Benzoyl peroxide

D. Hydroquinone

84. The polymerization of self-curing resin takes faster in______________?
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A. Cold water

B. Under pressure

C. In vaccum

D. Hot water
85. The type of spatula used to mix composite is________________?
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A. Plastic

B. Stainless steel

C. None of the above

D. Iron

88. For photo-curing the composite resin the light source______________?
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A. Is fiber optic

B. Will cure composite upto a depth of 5 millimeter thickness

C. Need no protection while in use

D. Should be held at a millimeter distance from the restoration
89. A good adhesive should possess all of the following EXCEPT________________?
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A. High flow

B. High adherend wetting

C. Low contact angle

D. High contact angle
90. The stiffness of a dental gold alloy is determined by its________________?
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A. Flow

B. Proportional limit

C. Ultimate tensile strength

D. Modulus of elasticity
91. The main advantage of composites over unfilled direct filling resin is their_____________?
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A. Higher solubility in saliva

B. Lower modulus of elasticity

C. Lower thermal co-efficient of expansion

D. Esthetic excellence

93. Light cure system, side effect is____________?
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A. Cataract

B. Retinal damage

C. Conjunctivitis

D. Iritis

94. Sub surface porosity can be decreased by_______________?
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A. Increasing the melting temperature

B. Increasing the mould temperature

C. Decreasing the sprue length

D. Decreasing the sprue thickness
95. The proportional limit is defined as______________?
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A. The maximum stress in a structure

B. The maximum elongation under tension that can be measured before failure

C. The maximum stress that can be induced without permanent deformation

D. The minimum force required to cause a structure to break

96. Non metal which conducts elactricity______________?
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A. Acrylic

B. Porcelain

C. Graphite

D. Carbon

97. One of the claims for the superiority composite resin restoration over silicate cement restorations is that the resin restorations_____________?
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A. Have a higher coefficient of thermal expansion

B. Are practically insoluble in oral fluids

C. Adapt to the walls of the cavity better

D. Prevent galvanic action

99. Angles between Adhesive and Adherent is Zero degree, it indicates_______________?
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A. Complete wetting of surfaces

B. Irregularities present between Adherent surfaces

C. Adherent and Adhesive molecules are tangent to each other

D. Rough surfaces between Adhesive & Adherent

100. Composite resins in comparison to acrylic have_______________?
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A. High abrasive resistance

B. High water absorption

C. High polymerization shrinkage

D. Low compressive strength