Biomaterial Test

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Biomaterial Test

1 / 60

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

a. Polyvinyl siloxane

b. Condensation silicone

c. Polyether

d. Polysulfied

2 / 60

Bis-GMA is a reaction product of 😕

a. Bis-phenol-A and methyl methacrylate

b. Bis-phenol-A and urethane dimethacrylate

c. Urethane dimethacrylate and glycidyl

d. Bis-phenol-A and glycidyl methacrylate

3 / 60

Crystal structures of metals are all the following except 😕

a. Cubic

b. Monoclinic

c. Circular

d. Tetragonal

4 / 60

In dental porcelains metallic oxides provide 😕

a. Color and increases the strength

b. Color but decreases the strength

c. Provides refractile property and increases strength

d. Color and provides refractile property

5 / 60

Which of the following statements about curing of composites are true ?

a. Light from an argon laser will activate polymerization.

b. Exposure times of 2 to 3 seconds are needed for polymerization with visible light.

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

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

6 / 60

The reason zinc oxide eugenol cement is used as a temporary restoration 😕

a. It has poor tensile strength

b. It has an obtudant effect

c. It does not have anticariogenic activity

d. It does not form reparative dentin

7 / 60

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

a. Requires higher forces of condensation

b. Requires more mercury for trituration

c. Requires less amalgamation time

d. Have longer setting time

8 / 60

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

a. Gold alloy

b. Ceramic

c. Amalgam

d. Silver alloys

9 / 60

Which of the following statements apply to the packable composites ?

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

b. They are radiolucent.

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

d. Radiopaque

10 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Vulcanizing

b. Sintering

c. Fusing

d. Fritting

11 / 60

Silver has all the following characteristics except 😕

a. Silver points serve as a root canal filling material

b. Whitens when added to alloys

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

d. Addition of palladium to silver increases corrosion

12 / 60

Which of the following base is contraindicated for composites ?

a. Zinc phosphate

b. Glass ionomer cement

c. Zinc oxide eugenol

d. Calcium hydroxide

13 / 60

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

a. 2 mm

b. 1 mm

c. 3 mm

d. 4 mm

14 / 60

Chemically cured resin shrinks:?

a. Towards the center of bulk of material

b. Away from the light source

c. On the base only

d. On the surface only

15 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Condensation silicones

b. Polysulfides

c. Addition silicones

d. Polyether

16 / 60

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

a. Polyether

b. Polysulfides

c. Condensation silicones

d. Addition silicones

17 / 60

All are properties of waxes except 😕

a. Creep

b. Plastic deformation

c. Flow

d. Solidification shrinkage

18 / 60

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

a. It decreases the time for syneresis to occur

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

c. It is the easiest method of removal

d. Faster rate of removal increases the yield strength

19 / 60

In the cavities which are more than 2mm deep a light-cured restoration is 😕

a. Not indicated

b. Fifth generation bonding agent should be applied

c. Cured for longer period

d. Restoration should be build in increments

20 / 60

Which of the following properties are higher for microhybrid composites than for microfilled composites ?

a. Water sorption

b. Thermal expansion

c. Modulus of elasticity

d. Polymerization shrinkage

21 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It is harder and has less flow

b. It is sticky

c. It has low melting temperature

d. It provides luster to the pattern

22 / 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. 30 mg Hg/m3 of air

b. 0.04 mg Hg/m3 of air

c. 0.05 mg Hg/m3 of air

d. 100 mg Hg/m3 of air

23 / 60

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

a. Titanium-molybdenum-vanadium alloy

b. Titanium-aluminum-vanadium alloy

c. Platinum-aluminum-vanadium alloy

d. Titanium-platinum-aluminum alloy

24 / 60

Impression compound is characterized by 😕

a. Crystalline in nature with high thermal conductivity

b. Crystalline in nature with definite melting point

c. Amorphous in nature with low thermal conductivity

d. Amorphous in nature with high thermal conductivity

25 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. After metal is tempered

b. Several times in air

c. Under compression

d. Under low temperature

26 / 60

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

a. Beading wax

b. Carding wax

c. Utility wax

d. Boxing wax

27 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Will take up water and expand if kept wet

b. Is an irreversible hydrocolloid impression material

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

d. Will be shrink as a result of syneresis

28 / 60

Metal has the following properties except 😕

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

b. Pure metals are not useful in dentistry

c. Metal is any element that ionizes positively in solution

d. Electroplated silver and copper are used in dies

29 / 60

A potentially toxic element in base metal alloys is 😕

a. Boron

b. Molybdenum

c. Beryllium

d. Magnesium

30 / 60

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

a. fluorite release

b. Floor carpeting

c. Baseboard heating

d. Amalgam scrap stored in a closed container

31 / 60

The common characteristic for pit and fissure sealant composite resins, acrylic appliances and elastomeric impression materials is :

a. All of them should be heated before using

b. All of them are a result of secondary reaction

c. All of them are polymers

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

32 / 60

Wrought metal 😕

a. Can be formed by working on a cast metal

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

c. Cannot be heat treated

d. Cannot be rendered corrosion resistant

33 / 60

Distortion on removal from undercuts in addition silicones is very less due to 😕

a. Stiffness of the material

b. Increased strain rate on unset material

c. Shrinkage of material

d. Lowest strain in compression

34 / 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

35 / 60

Which of these statements are correct in terms of preparing a correctly triturated mass of amalgam ?

a. An overmixed mass is removed readily from the capsule but is soupy in appearance.

b. A correctly triturated mass is a smooth homogeneous, and dull.

c. Dental amalgam is a mixture of silver alloys and mercury.

d. An undertriturated mass is crumbly and dull.

36 / 60

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

a. This material in granular form and is difficult

b. It is a bio-inert material

c. It is produced in block or granula form

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

37 / 60

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

a. Decreases ductility

b. Decreases the setting time

c. Produces contraction

d. Hydrolyzes the water if contaminated

38 / 60

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

a. Base plate wax

b. Carding wax

c. Sticky wax

d. Utility wax

39 / 60

The most commonly used implant type presently is 😕

a. Endosseous

b. Subperiosteal

c. Transosteal implant

d. Intramucosal implant

40 / 60

Contamination of zinc-containing amalgam by moisture during triturating or condensation :

a. Increases the setting time

b. Results in a marked expansion

c. Has no appreciable effect on properties except to the susceptibility to tarnish

d. Results in a sharp decrease in flow

41 / 60

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

a. Quartz

b. Silica

c. Water

d. Gypsum

42 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Regulate the setting time

b. Get a smooth surface

c. Increase strength

d. Reduce porosity

43 / 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

44 / 60

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

a. Wall carpeting

b. Floor carpeting

c. Baseboard heating

d. Amalgam scrap stored in a closed container

45 / 60

In dental plaster the main ingredient is 😕

a. Calcium phosphate

b. Calcium sulfate hemihydarate

c. Calcium sulfate dehydrate

d. Calcium anhydrate

46 / 60

Adhesion in composites is due to 😕

a. Cohesion

b. Mechanical interlocking

c. True chemical bonding to tooth structure

d. Presence of smear layer

47 / 60

Amalgam is less prone to corrosion 😕

a. If it contains 4-6% of copper

b. If devoid of the gamma 2 phase

c. If it contains 25-27% of tin

d. If it contains zinc

48 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Cobalt oxide

b. Chromium carbide

c. Ferric oxide

d. Chromium oxide

49 / 60

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

a. Teratogenesis

b. Carcinogenesis

c. Iatrogenesis

d. Biocompatibility

50 / 60

Stearic acid in impression compound 😕

a. Reduces plasticity

b. Increase setting time

c. Reduces flow

d. Reduces brittleness

51 / 60

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

a. Triturating precapsulated alloy and mercury

b. Mixing in a mortar and pestle

c. A cover over the mixing arms on a triturator

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

52 / 60

Which one of the following is not a criterion for a failed high-copper dental amalgam restorations ?

a. Creep of the restoration out of the cavity preparation in proximal areas

b. Wear facets along the occlusal contach areas

c. Marginal ditching along occlusal margins

d. Micrographs of alloys particles.

53 / 60

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

a. Polyether

b. Condensation silicone

c. Polysulfide

d. Addition silicone

54 / 60

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

a. Type I

b. Type III

c. Type II

d. Type IV

55 / 60

Which of these statements apply to the filler particles of composites ?

a. Microfilled

b. All are correct

c. Microfilled composites contain more filler than all-purpose composites.

d. Microhybrid composites contain as much as 84% filler by weight.

56 / 60

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

a. Intramucosal frames

b. Transosteal frames

c. Endosseus implants

d. Subperiosteal

57 / 60

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

a. Quartz

b. Lithium aluminum silicate

c. Barium glass

d. Colloidal silica

58 / 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 reduced

d. Mixing time is long

59 / 60

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

a. Decreased polymerization of the resin

b. Increased solubility of the resin

c. Subsequent oxidation of the tertiary amine

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

60 / 60

Minimum light exposure time for composite resins should be 😕

a. 10 sec

b. 20 sec

c. 40 sec

d. 5 sec

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