Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

All are properties of waxes except 😕

a. Solidification shrinkage

b. Creep

c. Plastic deformation

d. Flow

2 / 60

For proper wetting, contact angle should be ideally 😕

a. 900

b. 00

c. 450

d. 600

3 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. Reduce surface microporosities

b. To reduce gamma II particule

c. To prevent recurrent carries

d. To reduce discoloration

4 / 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 high-copper

d. Creep irregular low-copper

5 / 60

Commonly used filler in composite is 😕

a. Quartz

b. Colloidal silica

c. Aluminum

d. Glass

6 / 60

Alginate impression material deteriorates rapidly at 😕

a. Normal room temperature

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

c. Low temperature

d. Elevated temperature

7 / 60

Stearic acid in impression compound 😕

a. Increase setting time

b. Reduces plasticity

c. Reduces flow

d. Reduces brittleness

8 / 60

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

a. Higher strength, high creep, low corrosion

b. Higher strength, low creep, low corrosion

c. Low strength, low creep, low corrosion

d. Higher strength, high creep, high corrosion

9 / 60

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

a. Is used as a permanent restorative material in adults

b. The least irritant to the pulp

c. Has an obtudant effect on the pulp

d. Is the oldest luting agent

10 / 60

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

a. High malleafility of metal

b. Chemico-mechenical bonding

c. Chemical bonding

d. Hight ductility of metal

11 / 60

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

a. All of them are a result of secondary reaction

b. All of them should be heated before using

c. All of them are polymers

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

12 / 60

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

a. Amalgam

b. Porcelain

c. Gold alloy

d. Composite resin

13 / 60

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

a. Percentage elongation

b. Proportional limit

c. Yield strength

d. Flexibility

14 / 60

Elgiloy arch wire is 😕

a. Optical fiber arch wire

b. β-titanium arch wire

c. Gold alloy

d. Cobalt-chromium-nickel alloy

15 / 60

In dental plaster the main ingredient is 😕

a. Calcium sulfate hemihydarate

b. Calcium phosphate

c. Calcium anhydrate

d. Calcium sulfate dehydrate

16 / 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. Creep of the restoration out of the cavity preparation in proximal areas

c. Micrographs of alloys particles.

d. Marginal ditching along occlusal margins

17 / 60

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

a. 30 ng Hg/m3 of air

b. 0.05 mg Hg/m3 of air

c. 100 ng Hg/m3 of air

d. All are corrects

18 / 60

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

a. Gold alloys

b. Ceramic

c. Acrylic resin

d. Composite restorative resins

19 / 60

The cracks formed on the ceramic during cooling because 😕

a. The cooling of the outer and the inner layer occurs at the same rate

b. Due to external forces

c. The outer layer cools more rapidly than the interior

d. The inner layer cools more rapidly than the outer layer

20 / 60

Gold with high percentage elongation is best for 😕

a. To revert sagging during firing

b. To improve the castability

c. Increase the bond strength

d. To remove metallic oxide

21 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 10 seconds

b. Phosphoric acid for 10 seconds

c. Phosphoric acid for 60 seconds

d. Polyacrylic acid for 60 seconds

22 / 60

The main use of zinc oxide eugenol cement is 😕

a. Base

b. Permanent restoration

c. Temporary restoration

d. Indirect pulp capping agent

23 / 60

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

a. Waxe

b. Glass ionomer

c. Ceramic

d. Gold

24 / 60

Noble metal alloys are classified according to their 😕

a. Malleability

b. Castability

c. Dental function

d. Melting temperature

25 / 60

The main resin constituent of polishable composite resin is 😕

a. Urethane dimethacrylate

b. Polymethyl methacrylate

c. Cyanoacrylate

d. Polycaronate

26 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Lesser bony apposition

b. Prolonged healing time

c. Greater bony opposition

d. Presence of fibrous tissue

27 / 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. Coefficient of thermal expansion should not be compatible with porcelain

d. Should bond with dental porcelain

28 / 60

Hand instruments for composites are made of 😕

a. Teflon-coated metal

b. Titanium

c. Stainless steel

d. Carbon steel

29 / 60

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

a. Hydrolyzes the water if contaminated

b. Produces contraction

c. Decreases the setting time

d. Decreases ductility

30 / 60

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

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

b. The bonding agent forms a hybrid layer with enamel.

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

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

31 / 60

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

a. Silica

b. Feldspar

c. Potash

d. Kaolin

32 / 60

Impression compound is characterized by 😕

a. Amorphous in nature with low thermal conductivity

b. Crystalline in nature with high thermal conductivity

c. Crystalline in nature with definite melting point

d. Amorphous in nature with high thermal conductivity

33 / 60

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

a. Pure gold

b. Silicates

c. Amalgam

d. Composites

34 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Conserves the material

b. Increases surface smoothness

c. Increases strength and abrasive resistance

d. Decreases air voids in the restoration

35 / 60

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

a. Impact strength

b. Flexibility

c. Resilience

d. Toughness

36 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Get a smooth surface

b. Reduce porosity

c. Regulate the setting time

d. Increase strength

37 / 60

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

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

b. An undertriturated mass is crumbly and dull.

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

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

38 / 60

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

a. Ag-Hg

b. Sn-Hg

c. Cu-Sn

d. Ag-Su

39 / 60

When the gold content of gold alloys increases 😕

a. The corrosion resistance increases

b. The hardness decrease

c. Ductility decrease

d. The percentage elongation decrease

40 / 60

The main function of zinc in amalgam is 😕

a. To prevent the creep

b. To increase the shelf-life of an amalgam

c. To increase the longevity of amalgam after setting

d. To produce delayed expansion

41 / 60

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

a. Space lattice

b. Strain

c. Amorphous material

d. Stress

42 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Bis-phenol-A

b. Toluidine

c. Camphoroquinone

d. Benzoyl methyl ether

43 / 60

Polyether is different from other elastomers in the following aspects 😕

a. High stiffiness

b. Hydropholic in nature

c. Can not be used as light cure material

d. Low stiffness

44 / 60

In an alloy oxygen scavenger is 😕

a. Silver

b. Copper

c. Zinc

d. Palladium

45 / 60

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

a. Amalgam scrap stored in a closed container

b. fluorite release

c. Baseboard heating

d. Floor carpeting

46 / 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

47 / 60

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

a. Utility wax

b. Sticky wax

c. Base plate wax

d. Carding wax

48 / 60

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

a. Amalgam

b. Direct resin-filling material

c. Zinc phosphate

d. Silicate

49 / 60

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

a. Condensation silicones

b. Addition silicones

c. Polyether

d. Polysulfides

50 / 60

Porosity in denture base resins can be due to 😕

a. Excess heating of resin above its boiling point

b. Well flasking of wax pattern

c. Applying sufficient pressure during polymerization

d. Adequate mixing of liquid and powder components

51 / 60

One of the following statements which one is incorrect regarding addition silicones 😕

a. Dimensionally stable even after 1 week

b. Can be used in automixing devices

c. No evolution of any byproduct under all circumstances

d. Undetectable distortion on removal

52 / 60

Adhesion in composites is due to 😕

a. Mechanical interlocking

b. Presence of smear layer

c. Cohesion

d. True chemical bonding to tooth structure

53 / 60

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

a. It does not form reparative dentin

b. It has poor tensile strength

c. It does not have anticariogenic activity

d. It has an obtudant effect

54 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Zinc silicophoshpate

b. Polycardoxylate

c. Zinc phosphate

d. Calcum hydroxide

55 / 60

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

a. Iatrogenesis

b. Carcinogenesis

c. Teratogenesis

d. Biocompatibility

56 / 60

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

a. Results in a sharp decrease in flow

b. Results in a marked expansion

c. Increases the setting time

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

57 / 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.

58 / 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

59 / 60

Crystal structures of metals are all the following except 😕

a. Tetragonal

b. Cubic

c. Monoclinic

d. Circular

60 / 60

Metal has the following properties except 😕

a. All metals do not have same degrees of strength and plasticity

b. Electroplated silver and copper are used in dies

c. Metal is any element that ionizes positively in solution

d. Pure metals are not useful in dentistry

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The average score is 42%

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