Biomaterial Test

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Biomaterial Test

1 / 60

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

a. Yield strength

b. Percentage elongation

c. Flexibility

d. Proportional limit

2 / 60

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

a. Sulphide

b. Oxide

c. Gamma II Phase

d. Gamma I Phase

3 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Zinc oxide eugenol impression paste

b. Polyvinyl siloxane

c. Polyether

d. Alginate

4 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Hydropholic in nature

b. Can not be used as light cure material

c. High stiffiness

d. Low stiffness

5 / 60

Setting of plaster of Paris is a result of 😕

a. Solubility difference between hemihydrates and dehydrate

b. Interaction between hemihydrates and water

c. Loss of water from hemihydrates

d. Indirect interaction between hemihydrates

6 / 60

The primary difference between low- and high-copper amalgams is which of the following ?

a. The amount of copper and zinc

b. The amount of copper

c. The amount of copper and tin

d. The amount of copper and silver

7 / 60

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

a. Condensation silicone

b. Polyether

c. Polysulfide

d. Addition silicone

8 / 60

Chemically cured resin shrinks:?

a. On the base only

b. Away from the light source

c. On the surface only

d. Towards the center of bulk of material

9 / 60

Alginate impression material deteriorates rapidly at 😕

a. Low temperature

b. Normal room temperature

c. Elevated temperature

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

10 / 60

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

a. 1 mm

b. 3 mm

c. 2 mm

d. 4 mm

11 / 60

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

a. Kaolin

b. Feldspar

c. Potash

d. Silica

12 / 60

The following statements about dental porcelains are true except 😕

a. Undergoes firing shrinkage

b. Crystalline nature

c. Undergoes discoloration

d. It is brittle in nature

13 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Vulcanizing

b. Fusing

c. Sintering

d. Fritting

14 / 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

15 / 60

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

a. It has not more working time available

b. It takes more time for curing

c. It has more working time available

d. It is more sensitive to oxygen inhibitors

16 / 60

Gold with high percentage elongation is best for 😕

a. To revert sagging during firing

b. Increase the bond strength

c. To remove metallic oxide

d. To improve the castability

17 / 60

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

a. Base plate wax

b. Utility wax

c. Sticky wax

d. Carding wax

18 / 60

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

a. Springiness

b. Toughness

c. Brittleness

d. Hardness

19 / 60

Minimal thickness of base for adequate thermal insulation is 😕

a. 2 mm

b. 1 mm

c. 0.5 mm

d. 0.75 mm

20 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Polycardoxylate

b. Zinc silicophoshpate

c. Calcum hydroxide

d. Zinc phosphate

21 / 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 use of amalgam bonding restores the strength of the clinical crown to its original condition.

d. The most effective bonding agents contain copalite.

22 / 60

Resistance of a liquid to motion is called 😕

a. Creep

b. Diffusion

c. Viscosity

d. Springiness

23 / 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.

24 / 60

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

a. Polystyrene

b. Pheyl methacrylate

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

d. Poly (methyl methacrylate)

25 / 60

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

a. They are attached to natural teeth with cements,

b. Carbone steal

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

d. Artificial waxes teeth are attached

26 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

a. When the material is glossy

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

c. Exactly after four minutes after kneading

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

27 / 60

Elgiloy arch wire is 😕

a. Cobalt-chromium-nickel alloy

b. β-titanium arch wire

c. Gold alloy

d. Optical fiber arch wire

28 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can be cleaned properly

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

c. It can not lead to fungal growth

d. It can not lead to cleaned property

29 / 60

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

a. Gold alloy

b. Silver alloys

c. Amalgam

d. Ceramic

30 / 60

Biting force in the molar region ranges from 😕

a. 600-1000 N

b. 900-1000 N

c. 400-890 N

d. 1000-1300 N

31 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Camphoroquinone

b. Benzoyl methyl ether

c. Bis-phenol-A

d. Toluidine

32 / 60

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

a. Knoop hardness test

b. Vichers hardness test

c. Rockwell hardness test

d. Brinell hardness test

33 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Bond between agar and alginate is not very strong

b. Maximum details are not produced

c. Cost factor is high

d. Difficult to manipulate

34 / 60

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

a. Vacuum up a spill immediately

b. Sterilize amalgam scrap

c. Avoid touching freshly mixed amalgam

d. Avoid polishing amalgams

35 / 60

Which of the composites with the following fillers may be radiopaque ?

a. Barium glass

b. Quartz

c. Colloidal silica

d. Lithium aluminum silicate

36 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It is relatively soft and ductile

b. It is low in strength

c. Pure zinc has no application in dentistry

d. It does not oxidize

37 / 60

Materials having coefficient of thermal expansion close to the tooth structure 😕

a. Silicate cement

b. Unfilled

c. Glass ionomer cement

d. Amalgam

38 / 60

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

a. Springiness

b. Brittleness

c. Toughness

d. Hardness

39 / 60

Greater ratio fo zinc oxide to eugenol will have the following effect on setting time 😕

a. Does not alter setting time

b. Depends on rate of mixing

c. Increases setting time

d. Decreases setting time

40 / 60

When a mechanical device is used for mixing addition silicones 😕

a. Mixing time is long

b. More possibilities of contamination

c. There is no greater uniformity in proportioning and mixing

d. Mixing time is reduced

41 / 60

Calcium hydroxide is used for 😕

a. Pulp capping

b. To prevent recurrent caries

c. Reduce maginal leakage

d. Reinforce the restoration

42 / 60

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

a. Carnauba and candellia

b. Montan and Japan coco

c. Spermitic and bees wax

d. Paraffin and microcrystalline wax

43 / 60

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

a. increase strength

b. Reduce brittleness

c. Reduce porosity

d. Reduce firing shrinkage

44 / 60

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

a. Small particles

b. Conventional composites

c. Hybrid composites

d. Microfilled composites

45 / 60

Binder in the phosphate investment is 😕

a. Manganese dioxide

b. Magnesium oxide and monoammonium phosphate

c. Cristobalite

d. Phosphoric acid

46 / 60

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

a. Transosteal frames

b. Intramucosal frames

c. Endosseus implants

d. Subperiosteal

47 / 60

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

a. Gypsum

b. Quartz

c. Silica

d. Water

48 / 60

Silver has all the following characteristics except 😕

a. Whitens when added to alloys

b. Silver points serve as a root canal filling material

c. Silver in pure form is not used in dental restorations

d. Addition of palladium to silver increases corrosion

49 / 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. Carbide burs at high speed

d. Diamond burs at high speed

50 / 60

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

a. Specific temperature

b. Temperature of vaporization

c. Fusion temperature

d. Latent heat

51 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Polishing

b. Packing

c. Curing

d. Deflasking

52 / 60

When the gold content of gold alloys increases 😕

a. The hardness decrease

b. The percentage elongation decrease

c. The corrosion resistance increases

d. Ductility decrease

53 / 60

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

a. Polyether

b. Polysulfides

c. Addition silicones

d. Condensation silicones

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

c. Should be brittle

d. Should bond with dental porcelain

55 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 10 seconds

b. Phosphoric acid for 10 seconds

c. Polyacrylic acid for 60 seconds

d. Phosphoric acid for 60 seconds

56 / 60

Ideal method firing of porcelain is by using 😕

a. Longer firing at low temperatures

b. Shorter firing at low temperatures

c. Longer firing at high temperatures

d. Shorter firing at higher temperatures

57 / 60

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

a. No antibacterial action

b. High alkalinity

c. No Protein lysing effect

d. Low alkalinity

58 / 60

The most accurate polysulfide impressions are made by using a custom acrylic tray because 😕

a. More pressure can be applied during impression making

b. It can hold more amount of impression material

c. The tray does not distort during impression making

d. Custom tray made of plastic material ensures a uniform thickness of impression material

59 / 60

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

a. Cu-Sn

b. Ag-Sn

c. Ag-Hg

d. Sn-Hg

60 / 60

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

a. Condensation silicone

b. Polyether

c. Polyvinyl siloxane

d. Polysulfied

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