Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

a. Knoop hardness test

b. Brinell hardness test

c. Vichers hardness test

d. Rockwell hardness test

2 / 60

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

a. Polyether

b. Polysulfide

c. Addition silicone

d. Condensation silicone

3 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Polysulfides

b. Condensation silicones

c. Addition silicones

d. Polyether

4 / 60

Clinical significance of smear layer :

a. Bonded to tooth structure and prevents composite adhesion

b. Provides calcium for adhesion of composites

c. Increases the bonding action of the bonding agent

d. Improve the strength of the composite

5 / 60

Ideal method firing of porcelain is by using 😕

a. Shorter firing at higher temperatures

b. Longer firing at high temperatures

c. Shorter firing at low temperatures

d. Longer firing at low temperatures

6 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Camphoroquinone

b. Bis-phenol-A

c. Toluidine

d. Benzoyl methyl ether

7 / 60

The strain at which the plastic strain develops may be represented by 😕

a. Elastic limit, modulus of elasticity, tensile strength

b. Toughness, rigidity, resilience

c. Yield strength, tensile strength, toughness

d. Elastic limit, yield strength, proportional limit

8 / 60

Montan waxes have the following properties except 😕

a. Obtained by extraction from lignite

b. Have low melting points of 42oC

c. Are mineral waxes

d. Hard, brittle and lustrous

9 / 60

Stearic acid in impression compound 😕

a. Reduces flow

b. Increase setting time

c. Reduces brittleness

d. Reduces plasticity

10 / 60

In UV curing system the activator employed is 😕

a. Hydroquinone

b. Dibutyl phthalate

c. Benzoin methyl ether

d. Methyl methacrylate

11 / 60

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

a. Has the toxic properties of unreacted mercury

b. Is combined primarily with silver

c. Can form at the surface of amalgam restorations if heated to 0° C

d. Composite restorative resins

12 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

a. When the material cannot be intended by a blunt instrument

b. When the material is glossy

c. When it can be easily indented by a blunt instrument

d. Exactly after four minutes after kneading

13 / 60

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

a. Flow

b. Adhesion

c. Dimensional stability

d. Biocompatibility

14 / 60

Setting time of alginate can be better controlled by 😕

a. Temperature of water used of mixing

b. Changing water: powder ratio

c. Mixing time

d. Chemical accelerators and retarders

15 / 60

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

a. Cu-Sn

b. Ag-Su

c. Sn-Hg

d. Ag-Hg

16 / 60

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

a. Lithium aluminum silicate

b. Barium glass

c. Quartz

d. Colloidal silica

17 / 60

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

a. High strength

b. Esthetics

c. Ease of casting

d. Amalgam

18 / 60

A glaze is placed over the finished composite restoration to 😕

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

b. To reduce surface porosities

c. No provide a better peripheral seal

d. To change the shade

19 / 60

Nickel sensitivity in the general population is 😕

a. 11% for women

b. 3% for men

c. 3% for women

d. 1% in the overall population

20 / 60

The desirable quality of porcelain is 😕

a. Requirement of color

b. Toughness without brittleness

c. Thermal expansion

d. Translucency

21 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Conserves the material

b. Increases strength and abrasive resistance

c. Decreases air voids in the restoration

d. Increases surface smoothness

22 / 60

Glass ionomer cenment is not recommended for 😕

a. Class V restoration

b. Class III restoration

c. Class IV resoration

d. Class I restoration

23 / 60

Oxalates, carbonates, potassium, trisodium phosphates are added to alginate as 😕

a. Fillers

b. Accelerators

c. Retarders

d. Reactors

24 / 60

Alginate impression material deteriorates rapidly at 😕

a. Normal room temperature

b. Elevated temperature

c. Temperature does not cause any change in shelf-life

d. Low temperature

25 / 60

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

a. The amount of copper

b. The amount of copper and silver

c. The amount of copper and zinc

d. The amount of copper and tin

26 / 60

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

a. Space lattice

b. Amorphous material

c. Stress

d. Strain

27 / 60

The reason zinc oxide eugenol cement is used as a temporary restoration 😕

a. It has poor tensile strength

b. It has an obtudant effect

c. It does not have anticariogenic activity

d. It does not form reparative dentin

28 / 60

Binder in the phosphate investment is 😕

a. Magnesium oxide and monoammonium phosphate

b. Phosphoric acid

c. Manganese dioxide

d. Cristobalite

29 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Get a smooth surface

b. Reduce porosity

c. Increase strength

d. Regulate the setting time

30 / 60

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

a. Potash

b. Silica

c. Kaolin

d. Feldspar

31 / 60

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

a. Paraffin and microcrystalline wax

b. Spermitic and bees wax

c. Montan and Japan coco

d. Carnauba and candellia

32 / 60

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

a. 1-hour compressive strength spherical high-copper

b. Tensile strength spherical high-copper

c. Creep irregular low-copper

d. Creep irregular high-copper

33 / 60

Nickel in base metal alloys increase its 😕

a. Hardness and fusion temperature

b. Modulus of elasticity

c. S Ductility

d. Strength

34 / 60

Crystalline materials have 😕

a. No space lattice

b. No well-defined melting

c. Well-defined melting

d. Less stable space lattice

35 / 60

In a porcelain fused to metal restoration, the porcelain is-bonded to metal by 😕

a. Chemical bonding

b. High malleafility of metal

c. Hight ductility of metal

d. Chemico-mechenical bonding

36 / 60

Minimum light exposure time for composite resins should be 😕

a. 5 sec

b. 20 sec

c. 40 sec

d. 10 sec

37 / 60

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

a. Utility wax

b. Carding wax

c. Beading wax

d. Boxing wax

38 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Provide more strenght

b. Create tags

c. Remove smear layer

d. Facilitate mechanical bonding

39 / 60

In dental porcelains metallic oxides provide 😕

a. Color and provides refractile property

b. Provides refractile property and increases strength

c. Color and increases the strength

d. Color but decreases the strength

40 / 60

Adhesion in composites is due to 😕

a. Cohesion

b. True chemical bonding to tooth structure

c. Mechanical interlocking

d. Presence of smear layer

41 / 60

When the gold content of gold alloys increases 😕

a. The corrosion resistance increases

b. The percentage elongation decrease

c. Ductility decrease

d. The hardness decrease

42 / 60

Light source in the curing unit is usually 😕

a. Tungsten halogen light bulb

b. Infra red bulb

c. Sun light

d. Ultraviolet light bulb

43 / 60

Bis-GMA is a reaction product of 😕

a. Urethane dimethacrylate and glycidyl

b. Bis-phenol-A and glycidyl methacrylate

c. Bis-phenol-A and urethane dimethacrylate

d. Bis-phenol-A and methyl methacrylate

44 / 60

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

a. Glass ionomer cement

b. Composite resin

c. Silicate cement

d. Unfilled acrylic resin

45 / 60

Hydrocolloid impression should be removed from the mouth with a sharp jerk because 😕

a. Faster rate of removal increases the yield strength

b. It is the easiest method of removal

c. The brush heap structure of a gel responds more favorably to a sudden force

d. It decreases the time for syneresis to occur

46 / 60

Compared to lathe-cut alloy, spherical dental amalgam alloys 😕

a. Requires more mercury for trituration

b. Requires less amalgamation time

c. Have longer setting time

d. Requires higher forces of condensation

47 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It is relatively soft and ductile

b. It does not oxidize

c. It is low in strength

d. Pure zinc has no application in dentistry

48 / 60

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

a. Low alkalinity

b. No Protein lysing effect

c. High alkalinity

d. No antibacterial action

49 / 60

Which of the following base is contraindicated for composites ?

a. Glass ionomer cement

b. Zinc oxide eugenol

c. Calcium hydroxide

d. Zinc phosphate

50 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Copper

b. Silver

c. Nickel

d. Cobalt

51 / 60

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

a. A cover over the mixing arms on a triturator

b. Mixing in a mortar and pestle

c. Proportioning mercury and alloy into a friction-fit capsule

d. Triturating precapsulated alloy and mercury

52 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 45-600C

b. Far below the oral temperature

c. 37-450C

d. 100C higher than mouth temperature

53 / 60

Commonly used viscosity controller in composites is 😕

a. Polyurethanes

b. Methyl methacrylate

c. TEG-DMA

d. Bis-GAM

54 / 60

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

a. 0.05 mg Hg/m3 of air

b. 100 mg Hg/m3 of air

c. 30 mg Hg/m3 of air

d. 0.04 mg Hg/m3 of air

55 / 60

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

a. Has an obtudant effect on the pulp

b. Is used as a permanent restorative material in adults

c. Is the oldest luting agent

d. The least irritant to the pulp

56 / 60

The fluoride release from glass ionomer cement is 😕

a. 0.005 mg during the first week

b. 0.0005 mg during the first month

c. 0.75 mg during the first week

d. 0.075 mg during the first month

57 / 60

Following are the functions of impression compound except 😕

a. To make impression of edentulous ridge

b. To record mucostatic impressions

c. To make special tray for final impression

d. To make individual die impression with copper band

58 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Phosphoric acid for 10 seconds

b. Phosphoric acid for 60 seconds

c. Polyacrylic acid for 10 seconds

d. Polyacrylic acid for 60 seconds

59 / 60

Cobalt-chromium alloy is mostly used for the construction of 😕

a. Intramucosal frames

b. Subperiosteal

c. Transosteal frames

d. Endosseus implants

60 / 60

Hand instruments for composites are made of 😕

a. Titanium

b. Teflon-coated metal

c. Stainless steel

d. Carbon steel

Your score is

The average score is 62%

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