Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

a. Gold

b. Waxe

c. Glass ionomer

d. Ceramic

2 / 60

The most commonly used implant type presently is 😕

a. Intramucosal implant

b. Transosteal implant

c. Endosseous

d. Subperiosteal

3 / 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

4 / 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

5 / 60

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

a. Amalgam

b. Glass ionomer

c. Composite resin

d. Acrylic resin

6 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. Far below the oral temperature

b. 100C higher than mouth temperature

c. 37-450C

d. 45-600C

7 / 60

Main disadvantage of denture base soft reliner is 😕

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

b. It can not lead to cleaned property

c. It can not lead to fungal growth

d. It can be cleaned properly

8 / 60

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

a. Heat temperature

b. Fusion temperature

c. Vapor temperature

d. Temperature of specificity

9 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Dual impression for Partially edentulous patients

b. Wash impression for edentulous patients

c. Surgical paste

d. As interocclusal record material

10 / 60

Crystal structures of metals are all the following except 😕

a. Monoclinic

b. Circular

c. Tetragonal

d. Cubic

11 / 60

Which of the following statements about laboratory composites are true ?

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

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

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

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

12 / 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.

13 / 60

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

a. Vacuum up a spill immediately

b. Avoid touching freshly mixed amalgam

c. Sterilize amalgam scrap

d. Avoid polishing amalgams

14 / 60

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

a. Condensation silicone

b. Polyvinyl siloxane

c. Polysulfied

d. Polyether

15 / 60

Silver has all the following characteristics except 😕

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

b. Silver points serve as a root canal filling material

c. Whitens when added to alloys

d. Addition of palladium to silver increases corrosion

16 / 60

Which of the following statements apply to the packable composites ?

a. They are radiolucent.

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

c. Radiopaque

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

17 / 60

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

a. Gamma II Phase

b. Oxide

c. Gamma I Phase

d. Sulphide

18 / 60

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

a. Hight ductility of metal

b. Chemical bonding

c. High malleafility of metal

d. Chemico-mechenical bonding

19 / 60

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

a. Flexibility

b. Yield strength

c. Proportional limit

d. Percentage elongation

20 / 60

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

a. Endosseus implants

b. Subperiosteal

c. Transosteal frames

d. Intramucosal frames

21 / 60

Which of the following is used to alter contour of impression trays ?

a. Carding wax

b. Utility wax

c. Boxing wax

d. Beading wax

22 / 60

Gypsum investments should not be heated above 😕

a. 7000C

b. 10000C

c. 17000C

d. 4500C

23 / 60

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

a. Higher creep

b. Low corrosion

c. High corrosion

d. Higher strength

24 / 60

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

a. Resilience

b. Ductility

c. Creep

d. Fatigue

25 / 60

Which of the following mixing methods permits the escape of dental amalgam mercury vapor ?

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

b. A cover over the mixing arms on a triturator

c. Mixing in a mortar and pestle

d. Triturating precapsulated alloy and mercury

26 / 60

Biting force in the molar region ranges from 😕

a. 400-890 N

b. 600-1000 N

c. 1000-1300 N

d. 900-1000 N

27 / 60

Calcium hydroxide is used for 😕

a. Reinforce the restoration

b. Reduce maginal leakage

c. Pulp capping

d. To prevent recurrent caries

28 / 60

Hydrocolloid impression should be removed from the mouth with a sharp jerk because 😕

a. It decreases the time for syneresis to occur

b. It is the easiest method of removal

c. Faster rate of removal increases the yield strength

d. The brush heap structure of a gel responds more favorably to a sudden force

29 / 60

Stearic acid in impression compound 😕

a. Reduces plasticity

b. Increase setting time

c. Reduces flow

d. Reduces brittleness

30 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. Condense the unattacked gamma particles

b. Condense the unattacked gamma II particles

c. Condense the unattacked gamma I particles

d. To reduce gamma II particules

31 / 60

For luting purpose, the film thickness should be 😕

a. up to 75 μm

b. ideally 100 μm

c. minimum 50 μm

d. 25 μm or less

32 / 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

33 / 60

The main advantage of composites compared to silicates cement is 😕

a. Color matching with the tooth structure is excellent

b. Practically insoluble in oral fluids

c. High modulus of resilience

d. Coefficient of thermal expansion close to tooth structure

34 / 60

In UV curing system the activator employed is 😕

a. Benzoin methyl ether

b. Dibutyl phthalate

c. Hydroquinone

d. Methyl methacrylate

35 / 60

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

a. Amalgam scrap stored in a closed container

b. Floor carpeting

c. Baseboard heating

d. Wall carpeting

36 / 60

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

a. Ceramic

b. Gold alloys

c. Acrylic resin

d. Composite restorative resins

37 / 60

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

a. Aromatic sulfonate ester acts as a cross linking agent

b. The base paste consists of polyether polymer

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

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

38 / 60

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

a. Reduces burning sensation of paste

b. To increase setting time

c. Has a better reaction with zinc oxide

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

39 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It is harder and has less flow

b. It is sticky

c. It provides luster to the pattern

d. It has low melting temperature

40 / 60

Of the four types of gold casting alloys, the most commonly used for crowns and bridges is 😕

a. Type I

b. Type IV

c. Type II

d. Type III

41 / 60

Proportional limit is defined as :

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

b. A deformation resulting from an applied load

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

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

42 / 60

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

a. Floor carpeting

b. Amalgam scrap stored in a closed container

c. fluorite release

d. Baseboard heating

43 / 60

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

a. Condensation silicone

b. Polysulfide

c. Addition silicone

d. Polyether

44 / 60

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

a. Flexibility

b. Toughness

c. Resilience

d. Impact strength

45 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Can not be used as light cure material

b. Low stiffness

c. Hydropholic in nature

d. High stiffiness

46 / 60

Which of the following composites give rough surfaced finish ?

a. Hybrid composites

b. Microfilled composites

c. Conventional composites

d. Small particle filled composites

47 / 60

All are properties of waxes except 😕

a. Solidification shrinkage

b. Plastic deformation

c. Flow

d. Creep

48 / 60

Glass ionomer cenment is not recommended for 😕

a. Class V restoration

b. Class IV resoration

c. Class III restoration

d. Class I restoration

49 / 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

50 / 60

The appropriate proportion of polymer to monomer component of dental resin by volume is generally 😕

a. 1:3

b. 1:2

c. 2:1

d. 3:1

51 / 60

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

a. Ag-Su

b. Ag-Hg

c. Cu-Sn

d. Sn-Hg

52 / 60

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

a. Should bond with dental porcelain

b. Should be brittle

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

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

53 / 60

Wrought metal 😕

a. Cannot be heat treated

b. Can be formed by working on a cast metal

c. Cannot be rendered corrosion resistant

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

54 / 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. 100 mg Hg/m3 of air

c. 0.04 mg Hg/m3 of air

d. 30 mg Hg/m3 of air

55 / 60

Porcelain denture teeth 😕

a. Have decreased abrasion resistance than dentin

b. Are easy to grind and polish

c. Are more resistant of abrasion than gold

d. Have higher coefficient of thermal expansion than resin teeth

56 / 60

Which one of the following mixing methods permits the escape of dental amalgam mercury vapor ?

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

b. Triturating precapsulated alloy and mercury

c. Mixing in a mortar and pestle

d. A cover over the mixing arms on a triturator

57 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, tin, palladium and zinc

b. Silver, mercury, copper and zinc

c. Silver, tin, copper and zinc

d. Silver, mercury, copper and mercury

58 / 60

Which of the following material has a high coefficient of thermal expansion ?

a. Unfilled acrylic resin

b. Glass ionomer cement

c. Composite resin

d. Silicate cement

59 / 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. Difficult to manipulate

d. Cost factor is high

60 / 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 are polymers

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

d. All of them should be heated before using

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The average score is 42%

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