Make your own quiz Manage my Quizzes Plans / Features Guides and Help Contact Privacy & Security

2DD MCQ 218 Biomaterials Dr.Yin Sithoeun

A visually appealing infographic of dental biomaterials including images of dental implants, composites, and dental crowns, with scientific illustrations in the background.

Biomaterials Knowledge Quiz

Test your knowledge on biomaterials and dental materials with this engaging quiz. Designed for students and professionals in the dental field, this quiz covers a range of topics including properties of materials, practical applications, and clinical significance.

Key Features:

Multiple choice questions
Score tracking
Focus on dental and biomaterials

218 Questions54 MinutesCreated by LearningTooth23

1. Proportional limit is defined as :

σ� The stress/strain ratio within the elastic limit in a structure

σ� The maximum force required to cause a structure to break

σ� The maximum stress that can be induced without permanent deformation

σ� A deformation resulting from an applied load

2. Which of the following is a measure of resistance to fracture ?:

σ� Hardness

σ� Toughness

σ� Brittleness

σ� Springiness

3. Zinc oxide eugenal impression should be removed from oral cavity :

σ� When it can be easily indented by a blunt instrument

σ� When the material cannot be intended by a blunt instrument

σ� When the material is glossy

σ� Exactly after four minutes after kneading

4. Oil of clove is sometimes used in preference to eugenal in ZOE paste because :

σ� It increases mixing property of paste and therefore improves impression recorded

σ� Reduces burning sensation of paste

σ� Has a better reaction with zinc oxide

σ� To increase setting time

5. One of the following statements which one is incorrect regarding polyether :

σ� The main chain of polyether consists of copolymer of ethylene oxide and tetrahydrofuran

σ� The main chain consists of copolymer of methylene oxide and tetrahydrofuran

σ� Aromatic sulfonate ester acts as a cross linking agent

σ� The base paste consists of polyether polymer

6. Clinical significance of smear layer :

σ� Bonded to tooth structure and prevents composite adhesion

σ� Increases the bonding action of the bonding agent

σ� Provides calcium for adhesion of composites

σ� Improve the strength of the composite

7. The common characteristic for pit and fissure sealant composite resins, acrylic appliances and elastomeric impression materials is :

σ� All of them are polymers

σ� All of them can be employed as anterior filling materials

σ� All of them should be heated before using

σ� All of them are a result of secondary reaction

8. A cavity varnish used for lining the preparation for a dental amalgam restoration will :

σ� Provide thermal insulation

σ� Provide electrical insulation

σ� Reduce early marginal leakage tooth structure

σ� Provide strength of amalgam

9. The noble or base metal alloys used for PFM should have the following requisite :

σ� Should bond with dental porcelain

σ� Coefficient of thermal expansion should not be compatible with porcelain

σ� Its melting temperature should be low in comparison with firing temperature of porcelain 

σ� Should be brittle

10. Contamination of zinc-containing amalgam by moisture during triturating or condensation :

σ� Has no appreciable effect on properties except to the susceptibility to tarnish

σ� Results in a sharp decrease in flow

σ� Results in a marked expansion

σ� Increases the setting time

11. The restorative material used to restore a small portion of an anterior tooth should have which of the following properties ?

σ� Esthetics

σ� High strength

σ� Amalgam

σ� Ease of casting

12. An anterior fixed partial denture could have facings constructed of which of the following materials ?

σ� Composite resin

σ� Metal

σ� Amalgam

σ� Gold alloy

13. Which of the following sentences describes the construction of removable partial dentures ?

σ� Artificial acrylic teeth are attached

σ� They are attached to upper natural teeth with cements,

σ� They are attached to lower natural teeth with cements,

σ� They are attached to natural teeth with cements,

14. Which of these statements apply to the filler particles of composites ?

σ� Microhybrid composites contain as much as 84% filler by weight.

σ� Microfilled

σ� Microfilled composites contain more filler than all-purpose composites.

σ� All are correct

15. Which of the following initiator-accelerator systems is needed for a light-activated composite?

σ� Diketone-amine

σ� Peroxide-amine

σ� Organic acid-peroxide

σ� Organic acid-metal ion

16. Which of the following office conditions minimize the health hazard from spilled mercury ?

σ� Amalgam scrap stored in a closed container

σ� Floor carpeting

σ� Wall carpeting

σ� Baseboard heating

17. Which of the following represents the maximum safe concentration of mercury vapor in the breathing zone for a 40-hour workweek ?

σ� 0.05 mg Hg/m3 of air

σ� 30 ng Hg/m3 of air

σ� 100 ng Hg/m3 of air

σ� All are corrects

18. Which one of the following phases in dental amalgam restoration is most prone to electrochemical corrosion ?

σ� Sn-Hg

σ� Cu-Sn

σ� Ag-Su

σ� Ag-Hg

19. Which one of the following phases in dental amalgam restoration has the best mechanical properties ?

σ� Ag-Su

σ� Cu-Sn

σ� Sn-Hg

σ� Ag-Hg

Which one of the following mixing methods permits the escape of dental amalgam mercury vapor ?

σ� Mixing in a mortar and pestle

σ� Proportioning mercury and alloy into a friction-fit capsule

σ� Triturating precapsulated alloy and mercury

σ� A cover over the mixing arms on a triturator

21. A small portion of an anterior tooth would most likely be restored with which of the following ?

σ� Amalgam

σ� Composite resin

σ� Gold alloy

σ� Porcelain

A portion of a posterior tooth that is subject to high biting forces would likely be restored with which of the following ?

σ� Amalgam

σ� Composite resin

σ� Acrylic resin

σ� Glass ionomer

A direct restorative material used frequently to restore a portion of a posterior tooth that is subject to large biting forces would possess which of the following properties ?

σ� Esthetics

σ� High strength

σ� Ease of casting

σ� Thermal insulation

24. A full crown on a maxillary anterior tooth may be restored with which of the following restorative materials ?

σ� Ceramic

σ� Gold alloys

σ� Composite resin

σ� Amalgam

25. An anterior fixed partial denture could have facings constructed of which of the following materials ?

σ� Ceramic

σ� Gold alloy

σ� Silver alloys

σ� Amalgam

26. Which of the following sentences describes the construction of removable partial dentures ?

σ� They are attached to natural teeth with cements,

σ� They are removable and attached to teeth with clasps.

σ� Carbone steal

σ� Artificial waxes teeth are attached

27. Full denture bases are usually made from which of the following materials ?

σ� Composite restorative resins

σ� Gold alloys

σ� Acrylic resin

 Ceramic

Which of the following metals currently are used in dental alloys ?

σ� Gold

σ� Glass ionomer

σ� Waxe

σ� Ceramic

Which of the following materials are used for dental implants ?

σ� Gold alloys

 Cobalt and chromium alloys

σ� Titanium

σ� Metal alloys

Acrylic resins are used in which of the following ?

σ� Posterior inlays

σ� Denture bases

σ� Ceramic ( porcelain )-fused-to-metal crowns

σ� Anterior onlays

Which of the following statements about curing of composites are true ?

σ� Exposure times of 2 to 3 seconds are needed for polymerization with visible light.

σ� Before light activation, the base and catalyst pastes are mixed.

σ� Lights with both blue and red wavelengths are equally effective for polymerization.

σ� Light from an argon laser will activate polymerization.

32. Which of the composites with the following fillers may be radiopaque ?

σ� Quartz

σ� Lithium aluminum silicate

σ� Colloidal silica

σ� Barium glass

33. Which of the following polymer systems are used for the organic matrix in composites ?

σ� Bisphenol A-glycidyl methacrylate (Bis-GMA)

σ� Poly (methyl methacrylate)

σ� Polystyrene

σ� Pheyl methacrylate

34. Which of the following properties are higher for microhybrid composites than for microfilled composites ?

σ� Polymerization shrinkage

σ� Thermal expansion

σ� Water sorption

σ� Modulus of elasticity

35. Which of the following is the best choice of restorative material to achieve moderate to high strength, fluorite release, and esthetics ?

σ� Composite

σ� Compomer

σ� Hybrid ionomer

σ� Glass ionomer

36. Which of the following statements about laboratory composites are true ?

σ� Curing using light, heat, and pressure increase the wear resistance.

σ� Bridge prepared from laboratory composites require a metal substructure.

σ� Fiber reinforcement increases their strength but decrease their rigidity.

σ� Restorations prepared from laboratory composites typically are cemented with zinc phosphate cement.

37. Which of the following statements about adhesion of composite restorations to tooth structure are true ?

σ� Bonding is achieved to enamel by application of an acid etchant followed by application of a bonding agent and then the composites resin.

σ� The bonding agent forms a hybrid layer with enamel.

σ� The bonding agent forms a micromechanical bond with enamel but a chemical bond with dentin.

σ� Most bonding agent bond more effectively to a dry tooth surface.

38. Which of the following statements about compomers are true ?

σ� They are two-paste systems that self-cure within 2 to 3 minutes.

σ� Because of their resin content, they require a bonding agent for adhesion to tooth structure.

σ� They typically are recommended for class II restorations.

σ� They also are know as GIC

39. Which of the following statements apply to the packable composites ?

σ� Their depth of cure allows bulk polymerization, which has been shown to be clinically effective.

σ� Their wear rate is low (3.5 µm/year). Which is similar to that of amalgam.

σ� They are radiolucent.

σ� Radiopaque

40. Which one of the following office conditions minimize the health hazard from spilled mercury ?

σ� Baseboard heating

σ� Floor carpeting

σ� fluorite release

σ� Amalgam scrap stored in a closed container

Which one of the following represents the maximum safe concentration of mercury vapor in the breathing zone for a 40-hour work week ?

σ� 0.04 mg Hg/m3 of air

σ� 30 mg Hg/m3 of air

σ� 100 mg Hg/m3 of air

σ� 0.05 mg Hg/m3 of air

42. Once amalgamation has occurred, which of the following is true of mercury ?

σ� Is combined primarily with silver

σ� Has the toxic properties of unreacted mercury

σ� Can form at the surface of amalgam restorations if heated to 0° C

σ� Composite restorative resins

43. For each property, list the amalgam type (irregular low-copper, admixed high-copper, and spherical high-copper ) that has the highest value?.

σ� 1-hour compressive strength spherical high-copper

σ� Tensile strength spherical high-copper

σ� Creep irregular low-copper

σ� Creep irregular high-copper

44. Which of these statements are correct in terms of preparing a correctly triturated mass of amalgam ?

σ� An undertriturated mass is crumbly and dull.

σ� A correctly triturated mass is a smooth homogeneous, and dull.

σ� An overmixed mass is removed readily from the capsule but is soupy in appearance.

σ� Dental amalgam is a mixture of silver alloys and mercury.

45. Which statements are true for bonding of amalgam to tooth structure ?

σ� The most effective bonding agents contain copalite.

σ� Shear bond strength using amalgam bonding to teeth in clinically proven to be as high as that for bonding composites to teeth.

σ� The use of amalgam bonding restores the strength of the clinical crown to its original condition.

σ� The use of amalgam bonding reduces marginal leakage of amalgam restorations.

1. Which of the following phases in dental amalgam restoration is most prone to electrochemical properties ?

σ� Ag-Sn

σ� Cu-Sn

σ� Sn-Hg

σ� Ag-Hg

47. Which of the following phases in dental amalgam restoration has the best mechanical properties ?

σ� Ag-Sn

σ� Cu-Sn

σ� Sn-Hg

σ� Ag-Hg

48. Which of the following mixing methods permits the escape of dental amalgam mercury vapor ?

σ� Mixing in a mortar and pestle

σ� Proportioning mercury and alloy into a friction-fit capsule

σ� Triturating precapsulated alloy and mercury

σ� A cover over the mixing arms on a triturator

49. Which one of the following is not true about high-copper dental amalgam restorations ?

σ� Better corrosion resistance than low-copper dental amalgams

σ� Contain both Sn and Ag in the composition as well

σ� Produce excessive creep

σ� Restorations are more brittle than low-copper versions

50. Which one of the following is not a criterion for a failed high-copper dental amalgam restorations ?

σ� Marginal ditching along occlusal margins

σ� Creep of the restoration out of the cavity preparation in proximal areas

σ� Wear facets along the occlusal contach areas

σ� Micrographs of alloys particles.

51. Dental personnel can do which one of the following to limit their exposure to mercury ?

σ� Sterilize amalgam scrap

σ� Vacuum up a spill immediately

σ� Avoid touching freshly mixed amalgam

σ� Avoid polishing amalgams

52. The primary difference between low- and high-copper amalgams is which of the following ?

σ� The amount of copper

σ� The amount of copper and zinc

σ� The amount of copper and tin

σ� The amount of copper and silver

53. Ideally, the set amalgam should do which of the following ?

σ� Expand greatly to provide marginal seal against the tooth

σ� Shrink significantly to provide space for correction products to seal the margins

σ� Have little dimensional change

σ� Properties of amalgam

54. The physical properties most desirable in set amalgam are which of the following ?

σ� Higher strength, low creep, low corrosion

σ� Low strength, low creep, low corrosion

σ� Higher strength, high creep, low corrosion

σ� Higher strength, high creep, high corrosion

55. Higher mercury left in an amalgam leads to which of the following ?

σ� Higher creep

σ� Higher strength

σ� Low corrosion

σ� High corrosion

56. Which of the following occurs when dental amalgam is overmixed ?

σ� Compressive strength decreases

σ� Corrosion decreases

σ� Tensile strength increases

σ� Corrosion increases

57. The physical property measured in terms of the deformation of the structure per until dimensions is ?

σ� Stress

σ� Strain

σ� Space lattice

σ� Amorphous material

Resistance of a liquid to motion is called :?

σ� Viscosity

σ� Creep

σ� Diffusion

σ� Springiness

For proper wetting, contact angle should be ideally :?

σ� 900

σ� 600

σ� 450

σ� 00

60. Crystalline materials have :?

σ� No space lattice

σ� Less stable space lattice

σ� Well-defined melting

σ� No well-defined melting

Materials having coefficient of thermal expansion close to the tooth structure :?

σ� Unfilled

σ� Silicate cement

σ� Glass ionomer cement

σ� Amalgam

The temperature at which a solid changes into liquid is called :?

σ� Temperature of vaporization

σ� Fusion temperature

σ� Specific temperature

σ� Latent heat

Strain that occurs when the material is stressed to its proportional limit is called :?

σ� Resilience

σ� Flexibility

σ� Modulus of elasticity

σ� Toughness

64. Which of the following uses a hardened steel ball indenting tool ?

σ� Rockwell hardness test

σ� Vichers hardness test

σ� Brinell hardness test

σ� Knoop hardness test

65. A measure of ductility of a material is referred to as :?

σ� Proportional limit

σ� Percentage elongation

σ� Flexibility

σ� Yield strength

66. The energy absorbed by a material when it is stressed to its proportional limit is :?

σ� Impact strength

σ� Toughness

σ� Resilience

σ� Flexibility

67. The strain at which the plastic strain develops may be represented by :?

σ� Elastic limit, modulus of elasticity, tensile strength

σ� Elastic limit, yield strength, proportional limit

σ� Yield strength, tensile strength, toughness

σ� Toughness, rigidity, resilience

68. The tendency of stainless steel to break under repeated condition of cyclic stressing below the ultimate strength is :?

σ� Resilience

σ� Fatigue

σ� Creep

σ� Ductility

69. Thermal conductivity is proportional to :?

σ� Area of conduction

σ� Hardness of metal

σ� Fusion temperature

σ� Type of metal

70. Which of the following is a measure of resistance to fracture ?

σ� Hardness

σ� Toughness

σ� Brittleness

σ� Springiness

71. Regarding Knoop hardness number, which of the following material is closest to that of dentine (KHN 65) ?

σ� Amalgam

σ� Pure gold

σ� Composites

σ� Silicates

72. KHN of enamel is :?

σ� 90-100

σ� 100

σ� 600

σ� 300

73. Which of the following material has a high coefficient of thermal expansion ?

σ� Silicate cement

σ� Unfilled acrylic resin

σ� Glass ionomer cement

σ� Composite resin

74. Biting force in the molar region ranges from :?

σ� 1000-1300 N

σ� 900-1000 N

σ� 400-890 N

σ� 600-1000 N

75. Side effects and complications resulting from treatment by a physician or dentist is :?

σ� Iatrogenesis

σ� Teratogenesis

σ� Carcinogenesis

σ� Biocompatibility

76. In dental plaster the main ingredient is :?

σ� Calcium sulfate hemihydarate

σ� Calcium sulfate dehydrate

σ� Calcium anhydrate

σ� Calcium phosphate

77. Modifiers are added to plaster of Paris mainly to :?

σ� Increase strength

σ� Get a smooth surface

σ� Reduce porosity

σ� Regulate the setting time

78. The constituent that acts as a binder in the investment is :?

σ� Gypsum

σ� Quartz

σ� Silica

σ� Water

79. Setting of plaster of Paris is a result of :?

σ� Solubility difference between hemihydrates and dehydrate

σ� Interaction between hemihydrates and water

σ� Loss of water from hemihydrates

σ� Indirect interaction between hemihydrates

80. Gypsum investments should not be heated above :?

σ� 4500C

σ� 17000C

σ� 10000C

σ� 7000C

81. Binder in the phosphate investment is :?

σ� Cristobalite

σ� Magnesium oxide and monoammonium phosphate

σ� Manganese dioxide

σ� Phosphoric acid

82. Potato starch is contained in which impression material ?

σ� Impression compound

σ� Agar agar

σ� Impression plaster

σ� Potassium sulfate

83. Commonly used coloring agent in impression plaster is :?

σ� Congo red

σ� Indigo dye

σ� Alizarin red

σ� Metallic oxide

84. Impression plaster is a :?

σ� Mucocompressive material

σ� Thermoplastic material

σ� Mucostatic material

σ� Reversible impression material

85. Softening of impressing compound is best accomplished by :?

σ� Dry heat

σ� Open flame

σ� Water bath

σ� Oil bath

86. Impression compound is characterized by :?

σ� Crystalline in nature with definite melting point

σ� Amorphous in nature with high thermal conductivity

σ� Amorphous in nature with low thermal conductivity

σ� Crystalline in nature with high thermal conductivity

87. Following are the functions of impression compound except :?

σ� To make impression of edentulous ridge

σ� To make individual die impression with copper band

σ� To make special tray for final impression

σ� To record mucostatic impressions

88. Stearic acid in impression compound :?

σ� Reduces plasticity

σ� Reduces brittleness

σ� Reduces flow

σ� Increase setting time

89. Most common use of Zinc oxide eugenol paste :?

σ� Wash impression for edentulous patients

σ� Dual impression for Partially edentulous patients

σ� As interocclusal record material

σ� Surgical paste

90. Greater ratio fo zinc oxide to eugenol will have the following effect on setting time :?

σ� Decreases setting time

σ� Increases setting time

σ� Does not alter setting time

σ� Depends on rate of mixing

91. Which of the following properties would be of least importance, when selecting an impression material ?

σ� Dimensional stability

σ� Biocompatibility

σ� Flow

σ� Adhesion

92. The gelation temperature of agar hydrocolloid impression material should be :?

σ� Far below the oral temperature

σ� 37-450C

σ� 100C higher than mouth temperature

σ� 45-600C

93. Pick out the incorrect statement regarding alginate impressions :?

σ� May exhibit a fluid exudates on the surface as a result of imbibitions

σ� Will be shrink as a result of syneresis

σ� Will take up water and expand if kept wet

σ� Is an irreversible hydrocolloid impression material

94. Alginate impression material deteriorates rapidly at :?

σ� Normal room temperature

σ� Elevated temperature

σ� Low temperature

σ� Temperature does not cause any change in shelf-life

95. Hydrocolloid impression should be removed from the mouth with a sharp jerk because :?

σ� It is the easiest method of removal

σ� Faster rate of removal increases the yield strength

σ� It decreases the time for syneresis to occur

σ� The brush heap structure of a gel responds more favorably to a sudden force

96. Thickness of the gel between the tray and tissue for either agar or alginate should always be at least :?

σ� 1 mm

σ� 2 mm

σ� 3 mm

σ� 4 mm

97. Setting time of alginate can be better controlled by :?

σ� Mixing time

σ� Temperature of water used of mixing

σ� Chemical accelerators and retarders

σ� Changing water: powder ratio

98. In alginate impression the final gel is :?

σ� Sodium sulphate

σ� Calcium sulphate

σ� Sodium alginate

σ� Calcium alginate

99. Oxalates, carbonates, potassium, trisodium phosphates are added to alginate as :?

σ� Accelerators

σ� Retarders

σ� Reactors

σ� Fillers

101. Which of the following is recommended as an adhesive to trays with polysulfides ?

σ� Polydimethyl siloxane

σ� Styrene-acrylonitrile

σ� Ethyl silicate

σ� Acrylic resin

100. Main disadvantage of laminate technique of making impression is : ?

σ� Bond between agar and alginate is not very strong

σ� Maximum details are not produced

σ� Cost factor is high

σ� Difficult to manipulate

102. Which has the highest viscoelastic property and requires more time to recover from deformation ?

σ� Condensation silicone

σ� Polysulfide

σ� Polyether

σ� Addition silicone

103. Ideal metal used for electroplating polysulfide impression is :?

σ� Cobalt

σ� Copper

σ� Nickel

σ� Silver

104. The most accurate polysulfide impressions are made by using a custom acrylic tray because :?

σ� Custom tray made of plastic material ensures a uniform thickness of impression material

σ� It can hold more amount of impression material

σ� More pressure can be applied during impression making

σ� The tray does not distort during impression making

105. The byproduct in condensation silicones is :?

σ� Ethyl alcohol

σ� Methyl alcohol

σ� Propyl alcohol

σ� Butyl alcohol

106. The greatest amount of dimensional change after setting is exhibited by :?

σ� Polysulfides

σ� Polyethers

σ� Condensation silicones

σ� Addition silicones

107. The catalyst used for condensation silicones is :?

σ� Lead dioxide

σ� Oleic acid

σ� Stannous octoate

σ� Platinum

108. The impression material which is routinely used in auto mixing devicee system is :?

σ� Polyvinyl siloxane

σ� Polyether

σ� Polysulfied

σ� Condensation silicone

109. Which of the following elastomers is suited for multiple cast pouring :?

σ� Polysulfide

σ� Condensation silicone

σ� Addition silicone

σ� Polyether

110. One of the following statements which one is incorrect regarding addition silicones :?

σ� No evolution of any byproduct under all circumstances

σ� Undetectable distortion on removal

σ� Dimensionally stable even after 1 week

σ� Can be used in automixing devices

111. Sulfur contamination from natural latex gloves inhibits the setting of :?

σ� Alginate

σ� Polyether

σ� Polyvinyl siloxane

σ� Zinc oxide eugenol impression paste

112. When a mechanical device is used for mixing addition silicones :?

σ� There is no greater uniformity in proportioning and mixing

σ� More possibilities of contamination

σ� Mixing time is reduced

σ� Mixing time is long

113. Distortion on removal from undercuts in addition silicones is very less due to :?

σ� Stiffness of the material

σ� Increased strain rate on unset material

σ� Lowest strain in compression

σ� Shrinkage of material

114. Polyether is different from other elastomers in the following aspects :?

σ� Low stiffness

σ� Hydropholic in nature

σ� Can not be used as light cure material

σ� High stiffiness

115. Stiffness of the material with passage of time is maximum in :?

σ� Polysulfides

σ� Polyether

σ� Condensation silicones

σ� Addition silicones

116. Hypersensitivity reactions like contact dermatitis is caused by :?

σ� Polysulfides

σ� Condensation silicones

σ� Addition silicones

σ� Polyether

117. The main ingredient of casting waxes is :?

σ� Candellila wax

σ� Carnauba wax

σ� Paraffin wax

σ� Gum dammar

118. All are properties of waxes except :?

σ� Creep

σ� Flow

σ� Solidification shrinkage

σ� Plastic deformation

119. The function of gum dammar in inlay wax is :?

σ� No resistance to carving

σ� No smoothness of pattern

σ� Less strength to wax

σ� To improve smoothness of pattern

120. Carnauba wax is preferred to candelilla wax as :?

σ� It is harder and has less flow

σ� It has low melting temperature

σ� It provides luster to the pattern

σ� It is sticky

121. Which of the following waxes used to align of castings before soldering ?

σ� Sticky wax

σ� Carding wax

σ� Utility wax

σ� Base plate wax

122. Which of the following is called periphery wax ?

σ� Sticky wax

σ� Bite registration wax

σ� Utility wax

σ� Beading wax

123. Which of the following is used to alter contour of impression trays ?

σ� Utility wax

σ� Carding wax

σ� Beading wax

σ� Boxing wax

124. Which of the following waxes is obtained from distillation of petroleum ?

σ� Paraffin and microcrystalline wax

σ� Carnauba and candellia

σ� Montan and Japan coco

σ� Spermitic and bees wax

125. Montan waxes have the following properties except :?

σ� Obtained by extraction from lignite

σ� Are mineral waxes

σ� Have low melting points of 42oC

σ� Hard, brittle and lustrous

126. The appropriate proportion of polymer to monomer component of dental resin by volume is generally :?

σ� 3:1

σ� 2:1

σ� 1:2

σ� 1:3

127. Working time of denture resin should be at least :?

σ� 5 minutes

σ� 10 minutes

σ� 15 minutes

σ� 20 minutes

128. Porosity in denture base resins can be due to :?

σ� Excess heating of resin above its boiling point

σ� Adequate mixing of liquid and powder components

σ� Applying sufficient pressure during polymerization

σ� Well flasking of wax pattern

129. Main disadvantage of denture base soft reliner is :?

σ� It has not to be changed over a period of time

σ� It can be cleaned properly

σ� It can not lead to fungal growth

σ� It can not lead to cleaned property

130. The maximum warpage of acrylic denture occurs during :?

σ� Packing

σ� Curing

σ� Deflasking

σ� Polishing

131. Color stability of cold-cured resins is inferior to that of heat cured resins due to :?

σ� Increased solubility of the resin

σ� Subsequent oxidation of the tertiary amine

σ� Variation in the molecular weight of the resin (low mol wt)

σ� Decreased polymerization of the resin

132. Property which distinguishes composites from filled acrylic resins :?

σ� Adhesive bonding between matrix and filler

σ� Bonding with tooth structure

σ� Bonding between coupling agent and filler

σ� Bonding between coupling agent and tooth structure

133. Bis-GMA is a reaction product of :?

σ� Bis-phenol-A and methyl methacrylate

σ� Bis-phenol-A and glycidyl methacrylate

σ� Bis-phenol-A and urethane dimethacrylate

σ� Urethane dimethacrylate and glycidyl

134. Commonly used filler in composite is :?

σ� Quartz

σ� Colloidal silica

σ� Aluminum

σ� Glass

135. Inorganic phase in a composite matrix :?

σ� Decreases the mechanical strength

σ� Increases coefficient of thermal expansion

σ� Increases the polymerization shrinkage

σ� Increases the mechanical strength

136. Commonly used viscosity controller in composites is :?

σ� Bis-GAM

σ� TEG-DMA

σ� Polyurethanes

σ� Methyl methacrylate

137. Which of the following composites give rough surfaced finish ?

σ� Conventional composites

σ� Microfilled composites

σ� Hybrid composites

σ� Small particle filled composites

138. The main advantage of composites compared to silicates cement is :?

σ� Practically insoluble in oral fluids

σ� Color matching with the tooth structure is excellent

σ� High modulus of resilience

σ� Coefficient of thermal expansion close to tooth structure

139. In visible light-cured composites photo initiator molecule is :?

σ� Toluidine

σ� Benzoyl methyl ether

σ� Camphoroquinone

σ� Bis-phenol-A

140. Minimum light exposure time for composite resins should be :?

σ� 5 sec

σ� 10 sec

σ� 20 sec

σ� 40 sec

141. Which of the following composite is recommended for non stress bearing anterior restoration ?

σ� Microfilled composites

σ� Hybrid composites

σ� Conventional composites

σ� Small particles

142. The light-cured restorative resins have advantages over chemically activated restorative resins as :?

σ� It has not more working time available

σ� It takes more time for curing

σ� It is more sensitive to oxygen inhibitors

σ� It has more working time available

143. One of the disadvantages of using quartz as filler in restorative resin is :?

σ� It cannot be polished

σ� It cause abrasion and wearing of opposing tooth surface

σ� It cannot be reduced to the size of microparticle composite

σ� It has low affinity for resin matrix

144. The main resin constituent of polishable composite resin is :?

σ� Polymethyl methacrylate

σ� Polycaronate

σ� Cyanoacrylate

 Urethane dimethacrylate

145. In UV curing system the activator employed is :?

σ� Benzoin methyl ether

σ� Methyl methacrylate

σ� Hydroquinone

σ� Dibutyl phthalate

146. Light source in the curing unit is usually :?

σ� Ultraviolet light bulb

σ� Infra red bulb

σ� Tungsten halogen light bulb

σ� Sun light

147. Most commonly used pit and fissure sealant is :?

σ� Unfilled acrylic

σ� Polyurethane

σ� Bis-GMA resin

σ� Filled acrylic

148. Adhesion in composites is due to :?

σ� Cohesion

σ� True chemical bonding to tooth structure

σ� Mechanical interlocking

σ� Presence of smear layer

149. Dispensing composite resins using a syringe is advantageous because it :?

σ� Increases strength and abrasive resistance

σ� Increases surface smoothness

σ� Conserves the material

σ� Decreases air voids in the restoration

150. The light from the visible light curing unit can cause :?

σ� Iritis

σ� Cataract

σ� Retinal damage

σ� Corneal ulceration

151. In deep caities, the resin which remains unpolymerized can cause :?

σ� Pulp inflammation

σ� Sagging of restoration

σ� Porosity in restoration

σ� Secondary caries

152. In the cavities which are more than 2mm deep a light-cured restoration is :?

σ� Not indicated

σ� Cured for longer period

σ� Restoration should be build in increments

σ� Fifth generation bonding agent should be applied

153. If the light cure resin is curd in increments, it helps in :?

σ� Compensating polymerization shrinkage

σ� Providing strength to the restoration

σ� Achieving complete polymerization

σ� Saving the application of bonding agent

154. Chemically cured resin shrinks:?

σ� Towards the center of bulk of material

σ� Away from the light source

σ� On the surface only

σ� On the base only

155. A glaze is placed over the finished composite restoration to :?

σ� No provide a better peripheral seal

σ� To reduce surface porosities

σ� Create a rough surface that is less receptive to extrinsic stain and plaque retention

σ� To change the shade

156. Excess composite from the labial surfaces can be removed by using :?

σ� Diamond burs at high speed

σ� Diamond burs at low to medium speed

σ� Carbide burs at high speed

σ� Carbide burs at low to medium speed

157. Hand instruments for composites are made of :?

σ� Stainless steel

σ� Teflon-coated metal

σ� Carbon steel

σ� Titanium

158. Which of the following base is contraindicated for composites ?

σ� Zinc phosphate

σ� Zinc oxide eugenol

σ� Calcium hydroxide

σ� Glass ionomer cement

159. Which of the following statements is true regarding zinc phosphate cement ?

σ� The least irritant to the pulp

σ� Has an obtudant effect on the pulp

σ� Is used as a permanent restorative material in adults

σ� Is the oldest luting agent

160. Glass ionomer cenment is not recommended for :?

σ� Class V restoration

σ� Class III restoration

σ� Class IV resoration

σ� Class I restoration

161. The cavity for a GIC restoration is preconditioned with :?

σ� Polyacrylic acid for 60 seconds

σ� Polyacrylic acid for 10 seconds

σ� Phosphoric acid for 60 seconds

σ� Phosphoric acid for 10 seconds

162. The fluoride release from glass ionomer cement is :?

σ� 0.75 mg during the first week

σ� 0.075 mg during the first month

σ� 0.005 mg during the first week

σ� 0.0005 mg during the first month

163. Proconditioning before GIC restoration is done in order to :?

σ� Create tags

σ� Facilitate mechanical bonding

σ� Remove smear layer

σ� Provide more strenght

164. The main use of zinc oxide eugenol cement is :?

σ� Permanent restoration

σ� Temporary restoration

σ� Base

σ� Indirect pulp capping agent

165. The reason zinc oxide eugenol cement is used as a temporary restoration :?

σ� It has an obtudant effect

σ� It does not form reparative dentin

σ� It has poor tensile strength

σ� It does not have anticariogenic activity

166. The most effective cement in stimulating tertiary dentin is :?

σ� Zinc phosphate

σ� Calcum hydroxide

σ� Zinc silicophoshpate

σ� Polycardoxylate

167. Which of the following properties of calcium hydroxide cement help in the formation of reparative dentin ?

σ� Low alkalinity

σ� No antibacterial action

σ� No Protein lysing effect

σ� High alkalinity

168. Calcium hydroxide is used for :?

σ� Pulp capping

σ� Reduce maginal leakage

σ� Reinforce the restoration

σ� To prevent recurrent caries

169. Minimal thickness of base for adequate thermal insulation is :?

σ� 0.5 mm

σ� 0.75 mm

σ� 1 mm

σ� 2 mm

170. For luting purpose, the film thickness should be :?

σ� 25 µm or less

σ� minimum 50 µm

σ� up to 75 µm

σ� ideally 100 µm

171. Cavity varnish should not be applied when the following is used as a filling material :?

σ� Amalgam

σ� Silicate

σ� Zinc phosphate

σ� Direct resin-filling material

172. Dental porcelains are manufactured by a process termed as :?

σ� Fritting

σ� Fusing

σ� Vulcanizing

σ� Sintering

173. The desirable quality of porcelain is :?

σ� Translucency

σ� Thermal expansion

σ� Toughness without brittleness

σ� Requirement of color

174. Strength of dental porcelain is dependent on :?

σ� No internal structure

σ� Rough

 Composition

σ� Resistance to fusion

175. Ideal method firing of porcelain is by using :?

σ� Shorter firing at higher temperatures

σ� Longer firing at low temperatures

σ� Longer firing at high temperatures

σ� Shorter firing at low temperatures

176. The following statements about dental porcelains are true except :?

σ� It is brittle in nature

σ� Undergoes firing shrinkage

σ� Undergoes discoloration

σ� Crystalline nature

177. In dental porcelains metallic oxides provide :?

σ� Color and increases the strength

σ� Color but decreases the strength

σ� Color and provides refractile property

σ� Provides refractile property and increases strength

178. Porcelain denture teeth :?

σ� Are easy to grind and polish

σ� Are more resistant of abrasion than gold

σ� Have decreased abrasion resistance than dentin

σ� Have higher coefficient of thermal expansion than resin teeth

179. In a porcelain fused to metal restoration, the porcelain is-bonded to metal by :?

σ� Chemical bonding

σ� Hight ductility of metal

σ� Chemico-mechenical bonding

σ� High malleafility of metal

180. The cracks formed on the ceramic during cooling because :?

σ� The outer layer cools more rapidly than the interior

σ� The inner layer cools more rapidly than the outer layer

σ� The cooling of the outer and the inner layer occurs at the same rate

σ� Due to external forces

181. Condensation of porcelain is done by all the methods except :?

σ� Spatulation method

σ� Vibration method

σ� Brush addition technique

σ� Ceramming method

182. In a porcelain fused to metal restoration, when the coefficient of thermal expansion of metal and porcelain are different :?

σ� Porcelain will crack on cooling

σ� Porcelain will not bond with metal

σ� Porcelain will wear off

σ� Porcelain will provide good shade

183. Wet porcelain is condensed properly before firing to enhance all the properties except : ?

σ� Reduce firing shrinkage

σ� Reduce brittleness

σ� Reduce porosity

σ� increase strength

184. Which of the following components acts as a refractory material in porcelain ?

σ� Feldspar

σ� Potash

σ� Kaolin

σ� Silica

185. Porcelain-bonded to metal is stronger when fired :?

σ� Under compression

σ� Several times in air

σ� After metal is tempered

σ� Under low temperature

186. Metal has the following properties except :?

σ� Metal is any element that ionizes positively in solution

σ� All metals do not have same degrees of strength and plasticity

σ� Pure metals are not useful in dentistry

σ� Electroplated silver and copper are used in dies

187. Crystal structures of metals are all the following except :?

σ� Cubic

σ� Tetragonal

σ� Monoclinic

σ� Circular

188. The temperature at which a solid changes to liquid is known as its :?

σ� Vapor temperature

σ� Heat temperature

σ� Fusion temperature

σ� Temperature of specificity

189. Gold casting alloys are classified as type I, II, III or IV among these, having highest hardness is :?

σ� Type I

σ� Type II

σ� Type III

σ� Type IV

190. Of the four types of gold casting alloys, the most commonly used for crowns and bridges is :?

σ� Type I

σ� Type II

σ� Type III

σ� Type IV

191. Nickel sensitivity in the general population is :?

σ� 3% for men

σ� 3% for women

σ� 11% for women

σ� 1% in the overall population

192. In an alloy oxygen scavenger is :?

σ� Copper

σ� Silver

σ� Zinc

σ� Palladium

193. When the gold content of gold alloys increases :?

σ� The corrosion resistance increases

σ� The percentage elongation decrease

σ� The hardness decrease

σ� Ductility decrease

194. Gold with high percentage elongation is best for :?

σ� Increase the bond strength

σ� To remove metallic oxide

σ� To improve the castability

σ� To revert sagging during firing

195. Passiveness of chrome cobalt alloys is due to formation of :?

σ� Chromium carbide

σ� Ferric oxide

σ� Cobalt oxide

σ� Chromium oxide

196. Silver has all the following characteristics except :?

σ� Silver in pure form is not used in dental restorations

σ� Addition of palladium to silver increases corrosion

σ� Whitens when added to alloys

σ� Silver points serve as a root canal filling material

197. Spot out incorrect statement regarding zinc in dentistry :?

σ� Pure zinc has no application in dentistry

σ� It is relatively soft and ductile

σ� It is low in strength

σ� It does not oxidize

198. A potentially toxic element in base metal alloys is :?

σ� Molybdenum

σ� Beryllium

σ� Boron

σ� Magnesium

199. All of the following are properties of Co-Cr-Ni wires except :?

σ� They can be heat treated

σ� They have excellent tarnish and corrosion resistance

σ� They cannot be soldered or welded

σ� Their hardness is comparable to stainless steel

200. Noble metal alloys are classified according to their :?

σ� Melting temperature

σ� Malleability

σ� Castability

σ� Dental function

201. Nickel in base metal alloys increase its :?

σ� Strength

σ� Hardness and fusion temperature

σ� Modulus of elasticity

σ� S Ductility

202. Greening effect of porcelain is due to :?

σ� Silver

σ� Platinum

σ� Palladium

σ� Golde

203. Elgiloy arch wire is :?

σ� Cobalt-chromium-nickel alloy

σ� Gold alloy

σ� Optical fiber arch wire

σ� β-titanium arch wire

204. Wrought metal :?

σ� Cannot be rendered corrosion resistant

σ� Can be formed by pouring molten metal into a mold

σ� Can be formed by working on a cast metal

σ� Cannot be heat treated

205. Conventional dental amalgam alloy contains :?

σ� Silver, tin, copper and zinc

σ� Silver, mercury, copper and zinc

σ� Silver, tin, palladium and zinc

σ� Silver, mercury, copper and mercury

206. The type of stress to which dental amalgam is more resistant to :?

σ� Shear stress

σ� Tensile stress

σ� Impact stress

σ� Compressive stress

207. Amalgam is less prone to corrosion :?

σ� If it contains 25-27% of tin

σ� If devoid of the gamma 2 phase

σ� If it contains 4-6% of copper

σ� If it contains zinc

208. Silver in the set amalgam alloy tends to have the following effect :?

σ� Produces contraction

σ� Decreases the setting time

σ� Hydrolyzes the water if contaminated

σ� Decreases ductility

209. The chemistry behind the condensation of the amalgam is to :?

σ� Condense the unattacked gamma II particles

σ� Condense the unattacked gamma particles

σ� Condense the unattacked gamma I particles

σ� To reduce gamma II particules

210. Compared to lathe-cut alloy, spherical dental amalgam alloys :?

σ� Requires less amalgamation time

σ� Requires higher forces of condensation

σ� Requires more mercury for trituration

σ� Have longer setting time

211. The product that is formed on the surface of the amalgam restoration and frequently result in discoloration is :?

σ� Sulphide

σ� Gamma II Phase

σ� Gamma I Phase

σ� Oxide

212. The main function of zinc in amalgam is :?

σ� To produce delayed expansion

σ� To increase the longevity of amalgam after setting

σ� To increase the shelf-life of an amalgam

σ� To prevent the creep

213. The purpose of burnishing the amalgam after condensation is to :?

σ� Reduce surface microporosities

σ� To reduce gamma II particule

σ� To reduce discoloration

σ� To prevent recurrent carries

214. The most commonly used implant type presently is :?

σ� Intramucosal implant

σ� Subperiosteal

σ� Transosteal implant

σ� Endosseous

215. The most commonly employed alloy combination for use in implants is :?

σ� Titanium-platinum-aluminum alloy

σ� Titanium-aluminum-vanadium alloy

σ� Platinum-aluminum-vanadium alloy

σ� Titanium-molybdenum-vanadium alloy

216. Cobalt-chromium alloy is mostly used for the construction of :?

σ� Intramucosal frames

σ� Transosteal frames

σ� Endosseus implants

σ� Subperiosteal

217. Which of the following statements is incorrect regarding hydroxyapatite as an implant material ?

σ� It is used for augmenting alveolar ridges of filling bony defects

σ� It is produced in block or granula form

σ� It is a bio-inert material

σ� This material in granular form and is difficult

218. The reason for hydroxyapatite coating on implant biomaterials is :?

σ� Lesser bony apposition

σ� Presence of fibrous tissue

σ� Prolonged healing time

σ� Greater bony opposition

{"name":"2DD MCQ 218 Biomaterials Dr.Yin Sithoeun", "url":"https://www.quiz-maker.com/QPREVIEW","txt":"Test your knowledge on biomaterials and dental materials with this engaging quiz. Designed for students and professionals in the dental field, this quiz covers a range of topics including properties of materials, practical applications, and clinical significance.Key Features:Multiple choice questionsScore trackingFocus on dental and biomaterials","img":"https:/images/course6.png"}