Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. After metal is tempered

b. Under low temperature

c. Under compression

d. Several times in air

2 / 60

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

a. Its melting temperature should be low in comparison with firing temperature of porcelain

b. Should be brittle

c. Should bond with dental porcelain

d. Coefficient of thermal expansion should not be compatible with porcelain

3 / 60

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

a. Baseboard heating

b. Wall carpeting

c. Amalgam scrap stored in a closed container

d. Floor carpeting

4 / 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. The least irritant to the pulp

d. Is the oldest luting agent

5 / 60

Strength of dental porcelain is dependent on 😕

a. Resistance to fusion

b. No internal structure

c. Composition

d. Rough

6 / 60

For luting purpose, the film thickness should be 😕

a. ideally 100 μm

b. 25 μm or less

c. minimum 50 μm

d. up to 75 μm

7 / 60

Working time of denture resin should be at least 😕

a. 10 minutes

b. 20 minutes

c. 15 minutes

d. 5 minutes

8 / 60

Gypsum investments should not be heated above 😕

a. 17000C

b. 7000C

c. 10000C

d. 4500C

9 / 60

Resistance of a liquid to motion is called 😕

a. Viscosity

b. Springiness

c. Creep

d. Diffusion

10 / 60

Excess composite from the labial surfaces can be removed by using 😕

a. Carbide burs at high speed

b. Diamond burs at high speed

c. Diamond burs at low to medium speed

d. Carbide burs at low to medium speed

11 / 60

Crystalline materials have 😕

a. Less stable space lattice

b. Well-defined melting

c. No space lattice

d. No well-defined melting

12 / 60

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

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

b. It is the easiest method of removal

c. Faster rate of removal increases the yield strength

d. It decreases the time for syneresis to occur

13 / 60

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

a. Retarders

b. Accelerators

c. Fillers

d. Reactors

14 / 60

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

a. Amalgam

b. Glass ionomer

c. Acrylic resin

d. Composite resin

15 / 60

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

a. The most effective bonding agents contain copalite.

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

c. The use of amalgam bonding reduces marginal leakage of amalgam restorations.

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

16 / 60

A glaze is placed over the finished composite restoration to 😕

a. To change the shade

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

c. No provide a better peripheral seal

d. To reduce surface porosities

17 / 60

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

a. Yield strength, tensile strength, toughness

b. Elastic limit, yield strength, proportional limit

c. Elastic limit, modulus of elasticity, tensile strength

d. Toughness, rigidity, resilience

18 / 60

If the light cure resin is curd in increments, it helps in 😕

a. Saving the application of bonding agent

b. Providing strength to the restoration

c. Compensating polymerization shrinkage

d. Achieving complete polymerization

19 / 60

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

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

b. Light from an argon laser will activate polymerization.

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

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

20 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Remove smear layer

b. Provide more strenght

c. Facilitate mechanical bonding

d. Create tags

21 / 60

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

a. Intramucosal frames

b. Endosseus implants

c. Subperiosteal

d. Transosteal frames

22 / 60

Alginate impression material deteriorates rapidly at 😕

a. Elevated temperature

b. Normal room temperature

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

d. Low temperature

23 / 60

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

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

b. An undertriturated mass is crumbly and dull.

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

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

24 / 60

Glass ionomer cenment is not recommended for 😕

a. Class IV resoration

b. Class I restoration

c. Class V restoration

d. Class III restoration

25 / 60

Most commonly used pit and fissure sealant is 😕

a. Bis-GMA resin

b. Filled acrylic

c. Unfilled acrylic

d. Polyurethane

26 / 60

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

a. No Protein lysing effect

b. No antibacterial action

c. Low alkalinity

d. High alkalinity

27 / 60

Condensation of porcelain is done by all the methods except 😕

a. Ceramming method

b. Vibration method

c. Brush addition technique

d. Spatulation method

28 / 60

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

a. Silicates

b. Amalgam

c. Composites

d. Pure gold

29 / 60

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

a. They are attached to lower natural teeth with cements,

b. They are attached to natural teeth with cements,

c. Artificial acrylic teeth are attached

d. They are attached to upper natural teeth with cements,

30 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Bis-phenol-A

b. Camphoroquinone

c. Benzoyl methyl ether

d. Toluidine

31 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Increase strength

b. Reduce porosity

c. Regulate the setting time

d. Get a smooth surface

32 / 60

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

a. The amount of copper and tin

b. The amount of copper and zinc

c. The amount of copper and silver

d. The amount of copper

33 / 60

Acrylic resins are used in which of the following ?

a. Denture bases

b. Anterior onlays

c. Posterior inlays

d. Ceramic ( porcelain )-fused-to-metal crowns

34 / 60

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

a. Have longer setting time

b. Requires higher forces of condensation

c. Requires less amalgamation time

d. Requires more mercury for trituration

35 / 60

The fluoride release from glass ionomer cement is 😕

a. 0.075 mg during the first month

b. 0.0005 mg during the first month

c. 0.75 mg during the first week

d. 0.005 mg during the first week

36 / 60

The energy absorbed by a material when it is stressed to its proportional limit is 😕

a. Flexibility

b. Toughness

c. Resilience

d. Impact strength

37 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. Condense the unattacked gamma II particles

b. Condense the unattacked gamma particles

c. Condense the unattacked gamma I particles

d. To reduce gamma II particules

38 / 60

Thermal conductivity is proportional to 😕

a. Fusion temperature

b. Area of conduction

c. Hardness of metal

d. Type of metal

39 / 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 form reparative dentin

d. It does not have anticariogenic activity

40 / 60

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

a. Contain both Sn and Ag in the composition as well

b. Restorations are more brittle than low-copper versions

c. Better corrosion resistance than low-copper dental amalgams

d. Produce excessive creep

41 / 60

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

a. Conventional composites

b. Hybrid composites

c. Microfilled composites

d. Small particles

42 / 60

Ideal method firing of porcelain is by using 😕

a. Longer firing at high temperatures

b. Shorter firing at higher temperatures

c. Shorter firing at low temperatures

d. Longer firing at low temperatures

43 / 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. Amalgam

c. Esthetics

d. Ease of casting

44 / 60

The constituent that acts as a binder in the investment is 😕

a. Water

b. Silica

c. Gypsum

d. Quartz

45 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Low stiffness

b. High stiffiness

c. Can not be used as light cure material

d. Hydropholic in nature

46 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 10 seconds

b. Phosphoric acid for 10 seconds

c. Polyacrylic acid for 60 seconds

d. Phosphoric acid for 60 seconds

47 / 60

Side effects and complications resulting from treatment by a physician or dentist is 😕

a. Teratogenesis

b. Carcinogenesis

c. Biocompatibility

d. Iatrogenesis

48 / 60

Impression compound is characterized by 😕

a. Crystalline in nature with high thermal conductivity

b. Crystalline in nature with definite melting point

c. Amorphous in nature with low thermal conductivity

d. Amorphous in nature with high thermal conductivity

49 / 60

Hand instruments for composites are made of 😕

a. Carbon steel

b. Stainless steel

c. Titanium

d. Teflon-coated metal

50 / 60

One of the disadvantages of using quartz as filler in restorative resin is 😕

a. It cannot be polished

b. It has low affinity for resin matrix

c. It cause abrasion and wearing of opposing tooth surface

d. It cannot be reduced to the size of microparticle composite

51 / 60

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

a. Triturating precapsulated alloy and mercury

b. Mixing in a mortar and pestle

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

d. A cover over the mixing arms on a triturator

52 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, tin, palladium and zinc

b. Silver, mercury, copper and zinc

c. Silver, mercury, copper and mercury

d. Silver, tin, copper and zinc

53 / 60

In a porcelain fused to metal restoration, when the coefficient of thermal expansion of metal and porcelain are different 😕

a. Porcelain will wear off

b. Porcelain will not bond with metal

c. Porcelain will provide good shade

d. Porcelain will crack on cooling

54 / 60

Commonly used viscosity controller in composites is 😕

a. Polyurethanes

b. TEG-DMA

c. Methyl methacrylate

d. Bis-GAM

55 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Bonding between coupling agent and filler

b. Bonding between coupling agent and tooth structure

c. Adhesive bonding between matrix and filler

d. Bonding with tooth structure

56 / 60

Greening effect of porcelain is due to 😕

a. Palladium

b. Platinum

c. Golde

d. Silver

57 / 60

Light source in the curing unit is usually 😕

a. Sun light

b. Ultraviolet light bulb

c. Tungsten halogen light bulb

d. Infra red bulb

58 / 60

Silver has all the following characteristics except 😕

a. Silver points serve as a root canal filling material

b. Whitens when added to alloys

c. Addition of palladium to silver increases corrosion

d. Silver in pure form is not used in dental restorations

59 / 60

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

a. Utility wax

b. Boxing wax

c. Carding wax

d. Beading wax

60 / 60

The following statements about dental porcelains are true except 😕

a. Crystalline nature

b. Undergoes firing shrinkage

c. Undergoes discoloration

d. It is brittle in nature

Your score is

The average score is 73%

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