Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

a. Temperature of specificity

b. Vapor temperature

c. Heat temperature

d. Fusion temperature

2 / 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. Produce excessive creep

d. Better corrosion resistance than low-copper dental amalgams

3 / 60

Setting of plaster of Paris is a result of 😕

a. Interaction between hemihydrates and water

b. Loss of water from hemihydrates

c. Solubility difference between hemihydrates and dehydrate

d. Indirect interaction between hemihydrates

4 / 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

5 / 60

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

a. Tensile stress

b. Impact stress

c. Compressive stress

d. Shear stress

6 / 60

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

a. Organic acid-metal ion

b. Diketone-amine

c. Peroxide-amine

d. Organic acid-peroxide

7 / 60

Which of the following base is contraindicated for composites ?

a. Zinc oxide eugenol

b. Calcium hydroxide

c. Zinc phosphate

d. Glass ionomer cement

8 / 60

The product that is formed on the surface of the amalgam restoration and frequently result in discoloration is 😕

a. Sulphide

b. Gamma I Phase

c. Gamma II Phase

d. Oxide

9 / 60

Proportional limit is defined as :

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

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

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

d. A deformation resulting from an applied load

10 / 60

Potato starch is contained in which impression material ?

a. Impression compound

b. Impression plaster

c. Potassium sulfate

d. Agar agar

11 / 60

The most commonly used implant type presently is 😕

a. Endosseous

b. Transosteal implant

c. Intramucosal implant

d. Subperiosteal

12 / 60

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

a. Ag-Hg

b. Cu-Sn

c. Sn-Hg

d. Ag-Sn

13 / 60

Which of the following statements about laboratory composites are true ?

a. Restorations prepared from laboratory composites typically are cemented with zinc phosphate cement.

b. Curing using light, heat, and pressure increase the wear resistance.

c. Bridge prepared from laboratory composites require a metal substructure.

d. Fiber reinforcement increases their strength but decrease their rigidity.

14 / 60

In UV curing system the activator employed is 😕

a. Benzoin methyl ether

b. Hydroquinone

c. Methyl methacrylate

d. Dibutyl phthalate

15 / 60

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

a. Fatigue

b. Creep

c. Resilience

d. Ductility

16 / 60

The light from the visible light curing unit can cause 😕

a. Retinal damage

b. Cataract

c. Iritis

d. Corneal ulceration

17 / 60

Which of the following statements is incorrect regarding hydroxyapatite as an implant material ?

a. It is a bio-inert material

b. It is used for augmenting alveolar ridges of filling bony defects

c. This material in granular form and is difficult

d. It is produced in block or granula form

18 / 60

Which of the following polymer systems are used for the organic matrix in composites ?

a. Bisphenol A-glycidyl methacrylate (Bis-GMA)

b. Polystyrene

c. Pheyl methacrylate

d. Poly (methyl methacrylate)

19 / 60

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

a. Provide strength of amalgam

b. Reduce early marginal leakage tooth structure

c. Provide thermal insulation

d. Provide electrical insulation

20 / 60

The catalyst used for condensation silicones is 😕

a. Stannous octoate

b. Platinum

c. Oleic acid

d. Lead dioxide

21 / 60

Commonly used coloring agent in impression plaster is 😕

a. Metallic oxide

b. Alizarin red

c. Congo red

d. Indigo dye

22 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. Far below the oral temperature

b. 100C higher than mouth temperature

c. 45-600C

d. 37-450C

23 / 60

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

a. Titanium-aluminum-vanadium alloy

b. Platinum-aluminum-vanadium alloy

c. Titanium-molybdenum-vanadium alloy

d. Titanium-platinum-aluminum alloy

24 / 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

25 / 60

When a mechanical device is used for mixing addition silicones 😕

a. There is no greater uniformity in proportioning and mixing

b. More possibilities of contamination

c. Mixing time is long

d. Mixing time is reduced

26 / 60

The cracks formed on the ceramic during cooling because 😕

a. The outer layer cools more rapidly than the interior

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

c. Due to external forces

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

27 / 60

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

a. Glass ionomer

b. Acrylic resin

c. Composite resin

d. Amalgam

28 / 60

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

a. Toughness

b. Springiness

c. Brittleness

d. Hardness

29 / 60

Stearic acid in impression compound 😕

a. Reduces brittleness

b. Reduces plasticity

c. Increase setting time

d. Reduces flow

30 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Low stiffness

b. Can not be used as light cure material

c. High stiffiness

d. Hydropholic in nature

31 / 60

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

a. Toughness, rigidity, resilience

b. Elastic limit, modulus of elasticity, tensile strength

c. Elastic limit, yield strength, proportional limit

d. Yield strength, tensile strength, toughness

32 / 60

In deep caities, the resin which remains unpolymerized can cause 😕

a. Porosity in restoration

b. Secondary caries

c. Sagging of restoration

d. Pulp inflammation

33 / 60

Which of the following statements about compomers are true ?

a. They also are know as GIC

b. Because of their resin content, they require a bonding agent for adhesion to tooth structure.

c. They are two-paste systems that self-cure within 2 to 3 minutes.

d. They typically are recommended for class II restorations.

34 / 60

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

a. Carbide burs at low to medium speed

b. Diamond burs at low to medium speed

c. Diamond burs at high speed

d. Carbide burs at high speed

35 / 60

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

a. Transosteal frames

b. Endosseus implants

c. Subperiosteal

d. Intramucosal frames

36 / 60

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

a. Is combined primarily with silver

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

c. Has the toxic properties of unreacted mercury

d. Composite restorative resins

37 / 60

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

a. Ag-Su

b. Sn-Hg

c. Ag-Hg

d. Cu-Sn

38 / 60

The main resin constituent of polishable composite resin is 😕

a. Urethane dimethacrylate

b. Polymethyl methacrylate

c. Polycaronate

d. Cyanoacrylate

39 / 60

Nickel sensitivity in the general population is 😕

a. 3% for women

b. 3% for men

c. 1% in the overall population

d. 11% for women

40 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Addition silicones

b. Polyether

c. Polysulfides

d. Condensation silicones

41 / 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 reduces marginal leakage of amalgam restorations.

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

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

42 / 60

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

a. Sn-Hg

b. Cu-Sn

c. Ag-Sn

d. Ag-Hg

43 / 60

Which of the following is called periphery wax ?

a. Beading wax

b. Sticky wax

c. Utility wax

d. Bite registration wax

44 / 60

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

a. Hydrolyzes the water if contaminated

b. Decreases the setting time

c. Produces contraction

d. Decreases ductility

45 / 60

The main use of zinc oxide eugenol cement is 😕

a. Permanent restoration

b. Base

c. Indirect pulp capping agent

d. Temporary restoration

46 / 60

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

a. Has an obtudant effect on the pulp

b. Is the oldest luting agent

c. The least irritant to the pulp

d. Is used as a permanent restorative material in adults

47 / 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

48 / 60

The desirable quality of porcelain is 😕

a. Requirement of color

b. Thermal expansion

c. Toughness without brittleness

d. Translucency

49 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can not lead to fungal growth

b. It can be cleaned properly

c. It can not lead to cleaned property

d. It has not to be changed over a period of time

50 / 60

Elgiloy arch wire is 😕

a. Cobalt-chromium-nickel alloy

b. Gold alloy

c. β-titanium arch wire

d. Optical fiber arch wire

51 / 60

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

a. Polysulfied

b. Polyvinyl siloxane

c. Polyether

d. Condensation silicone

52 / 60

All are properties of waxes except 😕

a. Plastic deformation

b. Flow

c. Solidification shrinkage

d. Creep

53 / 60

Minimal thickness of base for adequate thermal insulation is 😕

a. 0.5 mm

b. 0.75 mm

c. 1 mm

d. 2 mm

54 / 60

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

a. Zinc phosphate

b. Silicate

c. Direct resin-filling material

d. Amalgam

55 / 60

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

a. Silica

b. Water

c. Gypsum

d. Quartz

56 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Chromium oxide

b. Cobalt oxide

c. Chromium carbide

d. Ferric oxide

57 / 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. 30 mg Hg/m3 of air

c. 100 mg Hg/m3 of air

d. 0.04 mg Hg/m3 of air

58 / 60

Commonly used filler in composite is 😕

a. Colloidal silica

b. Quartz

c. Aluminum

d. Glass

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

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

d. Light from an argon laser will activate polymerization.

60 / 60

Which of the following materials are used for dental implants ?

a. Cobalt and chromium alloys

b. Metal alloys

c. Titanium

d. Gold alloys

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The average score is 56%

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