Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

Biting force in the molar region ranges from 😕

a. 400-890 N

b. 1000-1300 N

c. 600-1000 N

d. 900-1000 N

2 / 60

The main use of zinc oxide eugenol cement is 😕

a. Permanent restoration

b. Base

c. Indirect pulp capping agent

d. Temporary restoration

3 / 60

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

a. Subsequent oxidation of the tertiary amine

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

c. Decreased polymerization of the resin

d. Increased solubility of the resin

4 / 60

Setting of plaster of Paris is a result of 😕

a. Interaction between hemihydrates and water

b. Solubility difference between hemihydrates and dehydrate

c. Loss of water from hemihydrates

d. Indirect interaction between hemihydrates

5 / 60

One of the following statements which one is incorrect regarding polyether :

a. The main chain consists of copolymer of methylene oxide and tetrahydrofuran

b. The main chain of polyether consists of copolymer of ethylene oxide and tetrahydrofuran

c. The base paste consists of polyether polymer

d. Aromatic sulfonate ester acts as a cross linking agent

6 / 60

Which of the following statements about compomers are true ?

a. They typically are recommended for class II restorations.

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

c. They also are know as GIC

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

7 / 60

Chemically cured resin shrinks:?

a. Towards the center of bulk of material

b. On the base only

c. Away from the light source

d. On the surface only

8 / 60

The main function of zinc in amalgam is 😕

a. To produce delayed expansion

b. To increase the longevity of amalgam after setting

c. To prevent the creep

d. To increase the shelf-life of an amalgam

9 / 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

10 / 60

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

a. Adhesion

b. Biocompatibility

c. Dimensional stability

d. Flow

11 / 60

Following are the functions of impression compound except 😕

a. To make individual die impression with copper band

b. To record mucostatic impressions

c. To make impression of edentulous ridge

d. To make special tray for final impression

12 / 60

Stearic acid in impression compound 😕

a. Reduces brittleness

b. Reduces plasticity

c. Increase setting time

d. Reduces flow

13 / 60

Thickness of the gel between the tray and tissue for either agar or alginate should always be at least 😕

a. 4 mm

b. 3 mm

c. 2 mm

d. 1 mm

14 / 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

15 / 60

The catalyst used for condensation silicones is 😕

a. Oleic acid

b. Lead dioxide

c. Platinum

d. Stannous octoate

16 / 60

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

a. Carnauba and candellia

b. Montan and Japan coco

c. Paraffin and microcrystalline wax

d. Spermitic and bees wax

17 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 37-450C

b. 45-600C

c. Far below the oral temperature

d. 100C higher than mouth temperature

18 / 60

The light from the visible light curing unit can cause 😕

a. Iritis

b. Cataract

c. Corneal ulceration

d. Retinal damage

19 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, tin, copper and zinc

b. Silver, mercury, copper and zinc

c. Silver, mercury, copper and mercury

d. Silver, tin, palladium and zinc

20 / 60

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

a. Amalgam

b. Gold alloy

c. Porcelain

d. Composite resin

21 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Nickel

b. Silver

c. Copper

d. Cobalt

22 / 60

The temperature at which a solid changes into liquid is called 😕

a. Specific temperature

b. Latent heat

c. Fusion temperature

d. Temperature of vaporization

23 / 60

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

a. Requires higher forces of condensation

b. Requires more mercury for trituration

c. Have longer setting time

d. Requires less amalgamation time

24 / 60

Bis-GMA is a reaction product of 😕

a. Bis-phenol-A and urethane dimethacrylate

b. Bis-phenol-A and glycidyl methacrylate

c. Bis-phenol-A and methyl methacrylate

d. Urethane dimethacrylate and glycidyl

25 / 60

Which of the following uses a hardened steel ball indenting tool ?

a. Brinell hardness test

b. Knoop hardness test

c. Rockwell hardness test

d. Vichers hardness test

26 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Polyvinyl siloxane

b. Zinc oxide eugenol impression paste

c. Polyether

d. Alginate

27 / 60

For proper wetting, contact angle should be ideally 😕

a. 600

b. 450

c. 00

d. 900

28 / 60

Binder in the phosphate investment is 😕

a. Manganese dioxide

b. Phosphoric acid

c. Cristobalite

d. Magnesium oxide and monoammonium phosphate

29 / 60

Porcelain denture teeth 😕

a. Have decreased abrasion resistance than dentin

b. Are more resistant of abrasion than gold

c. Have higher coefficient of thermal expansion than resin teeth

d. Are easy to grind and polish

30 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Reduce porosity

b. Get a smooth surface

c. Regulate the setting time

d. Increase strength

31 / 60

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

a. Artificial waxes teeth are attached

b. They are attached to natural teeth with cements,

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

d. Carbone steal

32 / 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

33 / 60

The main advantage of composites compared to silicates cement is 😕

a. Practically insoluble in oral fluids

b. Color matching with the tooth structure is excellent

c. High modulus of resilience

d. Coefficient of thermal expansion close to tooth structure

34 / 60

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

a. Ag-Sn

b. Ag-Hg

c. Sn-Hg

d. Cu-Sn

35 / 60

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

a. High alkalinity

b. No antibacterial action

c. No Protein lysing effect

d. Low alkalinity

36 / 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. Proportioning mercury and alloy into a friction-fit capsule

c. Mixing in a mortar and pestle

d. Triturating precapsulated alloy and mercury

37 / 60

In UV curing system the activator employed is 😕

a. Methyl methacrylate

b. Dibutyl phthalate

c. Benzoin methyl ether

d. Hydroquinone

38 / 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

39 / 60

The fluoride release from glass ionomer cement is 😕

a. 0.005 mg during the first week

b. 0.75 mg during the first week

c. 0.0005 mg during the first month

d. 0.075 mg during the first month

40 / 60

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

a. Conventional composites

b. Hybrid composites

c. Small particles

d. Microfilled composites

41 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

a. When it can be easily indented by a blunt instrument

b. When the material cannot be intended by a blunt instrument

c. When the material is glossy

d. Exactly after four minutes after kneading

42 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Presence of fibrous tissue

b. Lesser bony apposition

c. Greater bony opposition

d. Prolonged healing time

43 / 60

Which of the following base is contraindicated for composites ?

a. Zinc phosphate

b. Glass ionomer cement

c. Calcium hydroxide

d. Zinc oxide eugenol

44 / 60

The most commonly used implant type presently is 😕

a. Intramucosal implant

b. Endosseous

c. Subperiosteal

d. Transosteal implant

45 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It is harder and has less flow

b. It has low melting temperature

c. It is sticky

d. It provides luster to the pattern

46 / 60

Which has the highest viscoelastic property and requires more time to recover from deformation ?

a. Polysulfide

b. Polyether

c. Condensation silicone

d. Addition silicone

47 / 60

The main resin constituent of polishable composite resin is 😕

a. Polycaronate

b. Urethane dimethacrylate

c. Polymethyl methacrylate

d. Cyanoacrylate

48 / 60

Wet porcelain is condensed properly before firing to enhance all the properties except : ?

a. Reduce brittleness

b. increase strength

c. Reduce firing shrinkage

d. Reduce porosity

49 / 60

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

a. Reduce early marginal leakage tooth structure

b. Provide thermal insulation

c. Provide strength of amalgam

d. Provide electrical insulation

50 / 60

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

a. Sterilize amalgam scrap

b. Vacuum up a spill immediately

c. Avoid polishing amalgams

d. Avoid touching freshly mixed amalgam

51 / 60

Greening effect of porcelain is due to 😕

a. Palladium

b. Golde

c. Silver

d. Platinum

52 / 60

Adhesion in composites is due to 😕

a. True chemical bonding to tooth structure

b. Cohesion

c. Presence of smear layer

d. Mechanical interlocking

53 / 60

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

a. Gypsum

b. Water

c. Silica

d. Quartz

54 / 60

Proportional limit is defined as :

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

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

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

d. A deformation resulting from an applied load

55 / 60

Polyether is different from other elastomers in the following aspects 😕

a. High stiffiness

b. Hydropholic in nature

c. Low stiffness

d. Can not be used as light cure material

56 / 60

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

a. Endosseus implants

b. Subperiosteal

c. Transosteal frames

d. Intramucosal frames

57 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. Several times in air

b. Under low temperature

c. After metal is tempered

d. Under compression

58 / 60

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

a. Ductility

b. Resilience

c. Fatigue

d. Creep

59 / 60

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

a. Direct resin-filling material

b. Silicate

c. Zinc phosphate

d. Amalgam

60 / 60

Which of the following statements apply to the packable composites ?

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

b. Radiopaque

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

d. They are radiolucent.

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