Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Copper

b. Nickel

c. Cobalt

d. Silver

2 / 60

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

a. Has the toxic properties of unreacted mercury

b. Composite restorative resins

c. Is combined primarily with silver

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

3 / 60

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

a. Reduces burning sensation of paste

b. It increases mixing property of paste and therefore improves impression recorded

c. Has a better reaction with zinc oxide

d. To increase setting time

4 / 60

The main ingredient of casting waxes is 😕

a. Candellila wax

b. Gum dammar

c. Carnauba wax

d. Paraffin wax

5 / 60

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

a. Chemico-mechenical bonding

b. High malleafility of metal

c. Chemical bonding

d. Hight ductility of metal

6 / 60

KHN of enamel is 😕

a. 600

b. 90-100

c. 300

d. 100

7 / 60

Working time of denture resin should be at least 😕

a. 10 minutes

b. 15 minutes

c. 5 minutes

d. 20 minutes

8 / 60

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 ?

a. Ease of casting

b. High strength

c. Esthetics

d. Thermal insulation

9 / 60

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

a. Carbone steal

b. They are attached to natural teeth with cements,

c. They are removable and attached to teeth with clasps.

d. Artificial waxes teeth are attached

10 / 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

11 / 60

Glass ionomer cenment is not recommended for 😕

a. Class I restoration

b. Class IV resoration

c. Class V restoration

d. Class III restoration

12 / 60

Thermal conductivity is proportional to 😕

a. Hardness of metal

b. Type of metal

c. Fusion temperature

d. Area of conduction

13 / 60

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

a. Type III

b. Type IV

c. Type I

d. Type II

14 / 60

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

a. Kaolin

b. Silica

c. Potash

d. Feldspar

15 / 60

A potentially toxic element in base metal alloys is 😕

a. Beryllium

b. Boron

c. Molybdenum

d. Magnesium

16 / 60

Inorganic phase in a composite matrix 😕

a. Decreases the mechanical strength

b. Increases the mechanical strength

c. Increases coefficient of thermal expansion

d. Increases the polymerization shrinkage

17 / 60

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

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

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

c. The most effective bonding agents contain copalite.

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

18 / 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

c. The amount of copper and silver

d. The amount of copper and zinc

19 / 60

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

a. Diketone-amine

b. Peroxide-amine

c. Organic acid-metal ion

d. Organic acid-peroxide

20 / 60

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

a. Requires more mercury for trituration

b. Requires higher forces of condensation

c. Have longer setting time

d. Requires less amalgamation time

21 / 60

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

a. Provide thermal insulation

b. Reduce early marginal leakage tooth structure

c. Provide strength of amalgam

d. Provide electrical insulation

22 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To prevent recurrent carries

b. Reduce surface microporosities

c. To reduce discoloration

d. To reduce gamma II particule

23 / 60

Color stability of cold-cured resins is inferior to that of heat cured resins due to 😕

a. Increased solubility of the resin

b. Variation in the molecular weight of the resin (low mol wt)

c. Decreased polymerization of the resin

d. Subsequent oxidation of the tertiary amine

24 / 60

The impression material which is routinely used in auto mixing devicee system is 😕

a. Polyether

b. Condensation silicone

c. Polyvinyl siloxane

d. Polysulfied

25 / 60

The light-cured restorative resins have advantages over chemically activated restorative resins as 😕

a. It is more sensitive to oxygen inhibitors

b. It has more working time available

c. It takes more time for curing

d. It has not more working time available

26 / 60

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

a. No evolution of any byproduct under all circumstances

b. Undetectable distortion on removal

c. Can be used in automixing devices

d. Dimensionally stable even after 1 week

27 / 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. Creep irregular high-copper

c. Tensile strength spherical high-copper

d. Creep irregular low-copper

28 / 60

Elgiloy arch wire is 😕

a. Gold alloy

b. β-titanium arch wire

c. Optical fiber arch wire

d. Cobalt-chromium-nickel alloy

29 / 60

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

a. Hybrid ionomer

b. Compomer

c. Composite

d. Glass ionomer

30 / 60

The temperature at which a solid changes to liquid is known as its 😕

a. Temperature of specificity

b. Heat temperature

c. Vapor temperature

d. Fusion temperature

31 / 60

Which of the following statements apply to the packable composites ?

a. Radiopaque

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

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

d. They are radiolucent.

32 / 60

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

a. High corrosion

b. Low corrosion

c. Higher strength

d. Higher creep

33 / 60

Ideal method firing of porcelain is by using 😕

a. Shorter firing at low temperatures

b. Longer firing at low temperatures

c. Shorter firing at higher temperatures

d. Longer firing at high temperatures

34 / 60

The type of stress to which dental amalgam is more resistant to 😕

a. Tensile stress

b. Impact stress

c. Shear stress

d. Compressive stress

35 / 60

Adhesion in composites is due to 😕

a. Mechanical interlocking

b. True chemical bonding to tooth structure

c. Presence of smear layer

d. Cohesion

36 / 60

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

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

b. Properties of amalgam

c. Have little dimensional change

d. Expand greatly to provide marginal seal against the tooth

37 / 60

All of the following are properties of Co-Cr-Ni wires except 😕

a. Their hardness is comparable to stainless steel

b. They can be heat treated

c. They cannot be soldered or welded

d. They have excellent tarnish and corrosion resistance

38 / 60

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

a. Amalgam

b. Composite resin

c. Gold alloy

d. Metal

39 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Decreases air voids in the restoration

b. Increases strength and abrasive resistance

c. Conserves the material

d. Increases surface smoothness

40 / 60

For proper wetting, contact angle should be ideally 😕

a. 600

b. 450

c. 900

d. 00

41 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Phosphoric acid for 10 seconds

b. Polyacrylic acid for 10 seconds

c. Polyacrylic acid for 60 seconds

d. Phosphoric acid for 60 seconds

42 / 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. Pure metals are not useful in dentistry

d. Metal is any element that ionizes positively in solution

43 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Polyether

b. Polysulfides

c. Addition silicones

d. Condensation silicones

44 / 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. 100 mg Hg/m3 of air

b. 0.04 mg Hg/m3 of air

c. 30 mg Hg/m3 of air

d. 0.05 mg Hg/m3 of air

45 / 60

The most commonly used implant type presently is 😕

a. Endosseous

b. Intramucosal implant

c. Subperiosteal

d. Transosteal implant

46 / 60

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

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

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

c. Should be brittle

d. Should bond with dental porcelain

47 / 60

Proportional limit is defined as :

a. A deformation resulting from an applied load

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

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

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

48 / 60

All are properties of waxes except 😕

a. Flow

b. Plastic deformation

c. Solidification shrinkage

d. Creep

49 / 60

Which of the following elastomers is suited for multiple cast pouring 😕

a. Polysulfide

b. Condensation silicone

c. Addition silicone

d. Polyether

50 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Wash impression for edentulous patients

b. Surgical paste

c. Dual impression for Partially edentulous patients

d. As interocclusal record material

51 / 60

Which of the following base is contraindicated for composites ?

a. Zinc oxide eugenol

b. Glass ionomer cement

c. Calcium hydroxide

d. Zinc phosphate

52 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Packing

b. Polishing

c. Curing

d. Deflasking

53 / 60

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

a. Polyethers

b. Polysulfides

c. Addition silicones

d. Condensation silicones

54 / 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 an obtudant effect

d. It has poor tensile strength

55 / 60

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

a. Vacuum up a spill immediately

b. Avoid polishing amalgams

c. Sterilize amalgam scrap

d. Avoid touching freshly mixed amalgam

56 / 60

Wrought metal 😕

a. Cannot be rendered corrosion resistant

b. Cannot be heat treated

c. Can be formed by working on a cast metal

d. Can be formed by pouring molten metal into a mold

57 / 60

Condensation of porcelain is done by all the methods except 😕

a. Vibration method

b. Brush addition technique

c. Spatulation method

d. Ceramming method

58 / 60

Which of the following composites give rough surfaced finish ?

a. Conventional composites

b. Hybrid composites

c. Small particle filled composites

d. Microfilled composites

59 / 60

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

a. Adhesion

b. Dimensional stability

c. Biocompatibility

d. Flow

60 / 60

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

a. Thermal expansion

b. Water sorption

c. Polymerization shrinkage

d. Modulus of elasticity

Your score is

The average score is 42%

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