Biomaterial Test

5 votes, 5 avg

164

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Biomaterial Test

1 / 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

2 / 60

The most commonly employed alloy combination for use in implants is 😕

a. Titanium-molybdenum-vanadium alloy

b. Titanium-aluminum-vanadium alloy

c. Titanium-platinum-aluminum alloy

d. Platinum-aluminum-vanadium alloy

3 / 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. Better corrosion resistance than low-copper dental amalgams

c. Produce excessive creep

d. Restorations are more brittle than low-copper versions

4 / 60

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

a. Has an obtudant effect on the pulp

b. The least irritant to the pulp

c. Is the oldest luting agent

d. Is used as a permanent restorative material in adults

5 / 60

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

a. Baseboard heating

b. Amalgam scrap stored in a closed container

c. Floor carpeting

d. fluorite release

6 / 60

Chemically cured resin shrinks:?

a. Away from the light source

b. On the base only

c. On the surface only

d. Towards the center of bulk of material

7 / 60

Following are the functions of impression compound except 😕

a. To record mucostatic impressions

b. To make impression of edentulous ridge

c. To make special tray for final impression

d. To make individual die impression with copper band

8 / 60

Thermal conductivity is proportional to 😕

a. Type of metal

b. Area of conduction

c. Fusion temperature

d. Hardness of metal

9 / 60

Crystal structures of metals are all the following except 😕

a. Circular

b. Tetragonal

c. Cubic

d. Monoclinic

10 / 60

Silver in the set amalgam alloy tends to have the following effect 😕

a. Decreases ductility

b. Produces contraction

c. Decreases the setting time

d. Hydrolyzes the water if contaminated

11 / 60

Cavity varnish should not be applied when the following is used as a filling material 😕

a. Direct resin-filling material

b. Amalgam

c. Zinc phosphate

d. Silicate

12 / 60

Proportional limit is defined as :

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

b. The stress/strain ratio within the elastic limit in a structure

c. The maximum force required to cause a structure to break

d. A deformation resulting from an applied load

13 / 60

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

a. Ag-Hg

b. Sn-Hg

c. Ag-Su

d. Cu-Sn

14 / 60

Ideal method firing of porcelain is by using 😕

a. Longer firing at low temperatures

b. Shorter firing at higher temperatures

c. Shorter firing at low temperatures

d. Longer firing at high temperatures

15 / 60

In dental porcelains metallic oxides provide 😕

a. Color but decreases the strength

b. Color and increases the strength

c. Color and provides refractile property

d. Provides refractile property and increases strength

16 / 60

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

a. All of them should be heated before using

b. All of them can be employed as anterior filling materials

c. All of them are a result of secondary reaction

d. All of them are polymers

17 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Vulcanizing

b. Fritting

c. Fusing

d. Sintering

18 / 60

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

a. Glass ionomer

b. Ceramic

c. Waxe

d. Gold

19 / 60

Binder in the phosphate investment is 😕

a. Manganese dioxide

b. Magnesium oxide and monoammonium phosphate

c. Phosphoric acid

d. Cristobalite

20 / 60

Which of the following statements apply to the packable composites ?

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

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

c. They are radiolucent.

d. Radiopaque

21 / 60

Commonly used coloring agent in impression plaster is 😕

a. Metallic oxide

b. Congo red

c. Alizarin red

d. Indigo dye

22 / 60

The tendency of stainless steel to break under repeated condition of cyclic stressing below the ultimate strength is 😕

a. Ductility

b. Creep

c. Resilience

d. Fatigue

23 / 60

Glass ionomer cenment is not recommended for 😕

a. Class I restoration

b. Class IV resoration

c. Class V restoration

d. Class III restoration

24 / 60

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

a. Baseboard heating

b. Amalgam scrap stored in a closed container

c. Wall carpeting

d. Floor carpeting

25 / 60

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

a. It cause abrasion and wearing of opposing tooth surface

b. It cannot be polished

c. It has low affinity for resin matrix

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

26 / 60

Stearic acid in impression compound 😕

a. Reduces plasticity

b. Increase setting time

c. Reduces flow

d. Reduces brittleness

27 / 60

Stiffness of the material with passage of time is maximum in 😕

a. Polyether

b. Addition silicones

c. Polysulfides

d. Condensation silicones

28 / 60

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

a. It decreases the time for syneresis to occur

b. Faster rate of removal increases the yield strength

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

d. It is the easiest method of removal

29 / 60

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

a. Ag-Hg

b. Sn-Hg

c. Cu-Sn

d. Ag-Sn

30 / 60

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

a. It does not form reparative dentin

b. It does not have anticariogenic activity

c. It has poor tensile strength

d. It has an obtudant effect

31 / 60

Gold casting alloys are classified as type I, II, III or IV among these, having highest hardness is 😕

a. Type III

b. Type II

c. Type IV

d. Type I

32 / 60

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

a. Montan and Japan coco

b. Carnauba and candellia

c. Paraffin and microcrystalline wax

d. Spermitic and bees wax

33 / 60

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

a. High malleafility of metal

b. Hight ductility of metal

c. Chemico-mechenical bonding

d. Chemical bonding

34 / 60

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

a. Microfilled

b. Microhybrid composites contain as much as 84% filler by weight.

c. All are correct

d. Microfilled composites contain more filler than all-purpose composites.

35 / 60

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

a. Silica

b. Potash

c. Kaolin

d. Feldspar

36 / 60

Which of the following composites give rough surfaced finish ?

a. Hybrid composites

b. Small particle filled composites

c. Conventional composites

d. Microfilled composites

37 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Benzoyl methyl ether

b. Toluidine

c. Camphoroquinone

d. Bis-phenol-A

38 / 60

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

a. Polymerization shrinkage

b. Modulus of elasticity

c. Water sorption

d. Thermal expansion

39 / 60

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

a. Hardness

b. Toughness

c. Springiness

d. Brittleness

40 / 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

41 / 60

The greatest amount of dimensional change after setting is exhibited by 😕

a. Polysulfides

b. Condensation silicones

c. Addition silicones

d. Polyethers

42 / 60

For proper wetting, contact angle should be ideally 😕

a. 600

b. 900

c. 450

d. 00

43 / 60

In dental plaster the main ingredient is 😕

a. Calcium sulfate dehydrate

b. Calcium sulfate hemihydarate

c. Calcium anhydrate

d. Calcium phosphate

44 / 60

Biting force in the molar region ranges from 😕

a. 600-1000 N

b. 1000-1300 N

c. 400-890 N

d. 900-1000 N

45 / 60

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

a. Wear facets along the occlusal contach areas

b. Marginal ditching along occlusal margins

c. Creep of the restoration out of the cavity preparation in proximal areas

d. Micrographs of alloys particles.

46 / 60

In alginate impression the final gel is 😕

a. Sodium sulphate

b. Sodium alginate

c. Calcium alginate

d. Calcium sulphate

47 / 60

Working time of denture resin should be at least 😕

a. 5 minutes

b. 15 minutes

c. 20 minutes

d. 10 minutes

48 / 60

Minimal thickness of base for adequate thermal insulation is 😕

a. 1 mm

b. 2 mm

c. 0.75 mm

d. 0.5 mm

49 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Polycardoxylate

b. Zinc silicophoshpate

c. Calcum hydroxide

d. Zinc phosphate

50 / 60

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

a. Ag-Hg

b. Cu-Sn

c. Sn-Hg

d. Ag-Su

51 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It provides luster to the pattern

b. It is sticky

c. It is harder and has less flow

d. It has low melting temperature

52 / 60

A measure of ductility of a material is referred to as 😕

a. Proportional limit

b. Yield strength

c. Percentage elongation

d. Flexibility

53 / 60

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

a. Properties of amalgam

b. Shrink significantly to provide space for correction products to seal the margins

c. Expand greatly to provide marginal seal against the tooth

d. Have little dimensional change

54 / 60

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

a. Flow

b. Dimensional stability

c. Biocompatibility

d. Adhesion

55 / 60

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

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

b. Light from an argon laser will activate polymerization.

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

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

56 / 60

Calcium hydroxide is used for 😕

a. To prevent recurrent caries

b. Reinforce the restoration

c. Pulp capping

d. Reduce maginal leakage

57 / 60

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

a. Intramucosal frames

b. Subperiosteal

c. Transosteal frames

d. Endosseus implants

58 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Wash impression for edentulous patients

b. As interocclusal record material

c. Surgical paste

d. Dual impression for Partially edentulous patients

59 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Cobalt oxide

b. Chromium oxide

c. Ferric oxide

d. Chromium carbide

60 / 60

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

a. Results in a marked expansion

b. Results in a sharp decrease in flow

c. Has no appreciable effect on properties except to the susceptibility to tarnish

d. Increases the setting time

Your score is

The average score is 86%

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