Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

Which of the following represents the maximum safe concentration of mercury vapor in the breathing zone for a 40-hour workweek ?

a. 30 ng Hg/m3 of air

b. All are corrects

c. 0.05 mg Hg/m3 of air

d. 100 ng Hg/m3 of air

2 / 60

In dental plaster the main ingredient is 😕

a. Calcium sulfate dehydrate

b. Calcium anhydrate

c. Calcium phosphate

d. Calcium sulfate hemihydarate

3 / 60

Polyether is different from other elastomers in the following aspects 😕

a. High stiffiness

b. Low stiffness

c. Can not be used as light cure material

d. Hydropholic in nature

4 / 60

Binder in the phosphate investment is 😕

a. Manganese dioxide

b. Phosphoric acid

c. Cristobalite

d. Magnesium oxide and monoammonium phosphate

5 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Get a smooth surface

b. Regulate the setting time

c. Increase strength

d. Reduce porosity

6 / 60

Calcium hydroxide is used for 😕

a. Pulp capping

b. To prevent recurrent caries

c. Reduce maginal leakage

d. Reinforce the restoration

7 / 60

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

a. Gold alloy

b. Porcelain

c. Amalgam

d. Composite resin

8 / 60

Adhesion in composites is due to 😕

a. True chemical bonding to tooth structure

b. Mechanical interlocking

c. Cohesion

d. Presence of smear layer

9 / 60

The main use of zinc oxide eugenol cement is 😕

a. Base

b. Temporary restoration

c. Permanent restoration

d. Indirect pulp capping agent

10 / 60

In a porcelain fused to metal restoration, when the coefficient of thermal expansion of metal and porcelain are different 😕

a. Porcelain will provide good shade

b. Porcelain will crack on cooling

c. Porcelain will wear off

d. Porcelain will not bond with metal

11 / 60

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

a. Mixing in a mortar and pestle

b. A cover over the mixing arms on a triturator

c. Triturating precapsulated alloy and mercury

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

12 / 60

Strain that occurs when the material is stressed to its proportional limit is called 😕

a. Toughness

b. Flexibility

c. Modulus of elasticity

d. Resilience

13 / 60

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

a. Expand greatly to provide marginal seal against the tooth

b. Have little dimensional change

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

d. Properties of amalgam

14 / 60

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

a. Silicate

b. Zinc phosphate

c. Amalgam

d. Direct resin-filling material

15 / 60

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

a. Type I

b. Type II

c. Type IV

d. Type III

16 / 60

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

a. Have longer setting time

b. Requires more mercury for trituration

c. Requires less amalgamation time

d. Requires higher forces of condensation

17 / 60

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

a. Polysulfides

b. Condensation silicones

c. Addition silicones

d. Polyether

18 / 60

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

a. Spermitic and bees wax

b. Montan and Japan coco

c. Paraffin and microcrystalline wax

d. Carnauba and candellia

19 / 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

20 / 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. A cover over the mixing arms on a triturator

d. Mixing in a mortar and pestle

21 / 60

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

a. It is a bio-inert material

b. It is produced in block or granula form

c. This material in granular form and is difficult

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

22 / 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. The tray does not distort during impression making

c. It can hold more amount of impression material

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

23 / 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

24 / 60

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

a. Ag-Hg

b. Sn-Hg

c. Ag-Sn

d. Cu-Sn

25 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Difficult to manipulate

b. Bond between agar and alginate is not very strong

c. Maximum details are not produced

d. Cost factor is high

26 / 60

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

a. Titanium-platinum-aluminum alloy

b. Titanium-aluminum-vanadium alloy

c. Platinum-aluminum-vanadium alloy

d. Titanium-molybdenum-vanadium alloy

27 / 60

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

a. Silica

b. Kaolin

c. Feldspar

d. Potash

28 / 60

Which of the following is called periphery wax ?

a. Sticky wax

b. Utility wax

c. Bite registration wax

d. Beading wax

29 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Polyether

b. Condensation silicones

c. Addition silicones

d. Polysulfides

30 / 60

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

a. Aromatic sulfonate ester acts as a cross linking agent

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

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

d. The base paste consists of polyether polymer

31 / 60

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

a. Condensation silicone

b. Polysulfied

c. Polyvinyl siloxane

d. Polyether

32 / 60

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

a. Ceramic

b. Gold

c. Waxe

d. Glass ionomer

33 / 60

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

a. 3 mm

b. 1 mm

c. 4 mm

d. 2 mm

34 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 37-450C

b. 45-600C

c. 100C higher than mouth temperature

d. Far below the oral temperature

35 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. May exhibit a fluid exudates on the surface as a result of imbibitions

b. Will be shrink as a result of syneresis

c. Will take up water and expand if kept wet

d. Is an irreversible hydrocolloid impression material

36 / 60

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

a. Transosteal frames

b. Subperiosteal

c. Endosseus implants

d. Intramucosal frames

37 / 60

Amalgam is less prone to corrosion 😕

a. If it contains zinc

b. If devoid of the gamma 2 phase

c. If it contains 4-6% of copper

d. If it contains 25-27% of tin

38 / 60

Metal has the following properties except 😕

a. Pure metals are not useful in dentistry

b. Metal is any element that ionizes positively in solution

c. All metals do not have same degrees of strength and plasticity

d. Electroplated silver and copper are used in dies

39 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Adhesive bonding between matrix and filler

b. Bonding between coupling agent and filler

c. Bonding between coupling agent and tooth structure

d. Bonding with tooth structure

40 / 60

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

a. Brittleness

b. Springiness

c. Toughness

d. Hardness

41 / 60

Which of the following base is contraindicated for composites ?

a. Zinc oxide eugenol

b. Calcium hydroxide

c. Zinc phosphate

d. Glass ionomer cement

42 / 60

A full crown on a maxillary anterior tooth may be restored with which of the following restorative materials ?

a. Composite resin

b. Gold alloys

c. Ceramic

d. Amalgam

43 / 60

Softening of impressing compound is best accomplished by 😕

a. Dry heat

b. Water bath

c. Oil bath

d. Open flame

44 / 60

If the light cure resin is curd in increments, it helps in 😕

a. Providing strength to the restoration

b. Achieving complete polymerization

c. Compensating polymerization shrinkage

d. Saving the application of bonding agent

45 / 60

In an alloy oxygen scavenger is 😕

a. Palladium

b. Zinc

c. Silver

d. Copper

46 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It is sticky

b. It provides luster to the pattern

c. It is harder and has less flow

d. It has low melting temperature

47 / 60

Ideal method firing of porcelain is by using 😕

a. Shorter firing at higher temperatures

b. Longer firing at low temperatures

c. Longer firing at high temperatures

d. Shorter firing at low temperatures

48 / 60

Which one of the following is not true about high-copper dental amalgam restorations ?

a. Produce excessive creep

b. Contain both Sn and Ag in the composition as well

c. Restorations are more brittle than low-copper versions

d. Better corrosion resistance than low-copper dental amalgams

49 / 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. Light from an argon laser will activate polymerization.

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

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

50 / 60

Potato starch is contained in which impression material ?

a. Agar agar

b. Potassium sulfate

c. Impression plaster

d. Impression compound

51 / 60

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

a. Acrylic resin

b. Gold alloys

c. Composite restorative resins

d. Ceramic

52 / 60

Most commonly used pit and fissure sealant is 😕

a. Filled acrylic

b. Polyurethane

c. Unfilled acrylic

d. Bis-GMA resin

53 / 60

The main ingredient of casting waxes is 😕

a. Carnauba wax

b. Candellila wax

c. Paraffin wax

d. Gum dammar

54 / 60

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

a. Barium glass

b. Colloidal silica

c. Lithium aluminum silicate

d. Quartz

55 / 60

Which of the following composites give rough surfaced finish ?

a. Conventional composites

b. Small particle filled composites

c. Microfilled composites

d. Hybrid composites

56 / 60

Chemically cured resin shrinks:?

a. Away from the light source

b. On the surface only

c. On the base only

d. Towards the center of bulk of material

57 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Phosphoric acid for 60 seconds

b. Polyacrylic acid for 60 seconds

c. Phosphoric acid for 10 seconds

d. Polyacrylic acid for 10 seconds

58 / 60

Side effects and complications resulting from treatment by a physician or dentist is 😕

a. Teratogenesis

b. Iatrogenesis

c. Carcinogenesis

d. Biocompatibility

59 / 60

Which of the following materials are used for dental implants ?

a. Gold alloys

b. Cobalt and chromium alloys

c. Titanium

d. Metal alloys

60 / 60

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

a. Ag-Sn

b. Sn-Hg

c. Cu-Sn

d. Ag-Hg

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The average score is 86%

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