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. Glass ionomer

b. Ceramic

c. Waxe

d. Gold

2 / 60

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

a. The amount of copper and tin

b. The amount of copper and silver

c. The amount of copper

d. The amount of copper and zinc

3 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

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

b. Exactly after four minutes after kneading

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

d. When the material is glossy

4 / 60

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

a. Flexibility

b. Resilience

c. Toughness

d. Impact strength

5 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 45-600C

b. 100C higher than mouth temperature

c. Far below the oral temperature

d. 37-450C

6 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. Pure zinc has no application in dentistry

b. It is relatively soft and ductile

c. It is low in strength

d. It does not oxidize

7 / 60

Biting force in the molar region ranges from 😕

a. 1000-1300 N

b. 900-1000 N

c. 400-890 N

d. 600-1000 N

8 / 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. Mixing in a mortar and pestle

c. Triturating precapsulated alloy and mercury

d. A cover over the mixing arms on a triturator

9 / 60

Which of the following statements is true regarding zinc phosphate cement ?

a. The least irritant to the pulp

b. Is the oldest luting agent

c. Is used as a permanent restorative material in adults

d. Has an obtudant effect on the pulp

10 / 60

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

a. Teratogenesis

b. Biocompatibility

c. Carcinogenesis

d. Iatrogenesis

11 / 60

Setting time of alginate can be better controlled by 😕

a. Changing water: powder ratio

b. Mixing time

c. Temperature of water used of mixing

d. Chemical accelerators and retarders

12 / 60

Condensation of porcelain is done by all the methods except 😕

a. Vibration method

b. Brush addition technique

c. Spatulation method

d. Ceramming method

13 / 60

Once amalgamation has occurred, which of the following is true of mercury ?

a. Can form at the surface of amalgam restorations if heated to 0° C

b. Is combined primarily with silver

c. Composite restorative resins

d. Has the toxic properties of unreacted mercury

14 / 60

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

a. Polyether

b. Polysulfides

c. Addition silicones

d. Condensation silicones

15 / 60

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

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

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

c. Light from an argon laser will activate polymerization.

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

16 / 60

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

a. Properties of amalgam

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

c. Have little dimensional change

d. Expand greatly to provide marginal seal against the tooth

17 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Zinc oxide eugenol impression paste

b. Polyether

c. Polyvinyl siloxane

d. Alginate

18 / 60

A potentially toxic element in base metal alloys is 😕

a. Beryllium

b. Molybdenum

c. Boron

d. Magnesium

19 / 60

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

a. Provide strength of amalgam

b. Reduce early marginal leakage tooth structure

c. Provide electrical insulation

d. Provide thermal insulation

20 / 60

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

a. It is produced in block or granula form

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

c. This material in granular form and is difficult

d. It is a bio-inert material

21 / 60

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

a. They are attached to natural teeth with cements,

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

c. Carbone steal

d. Artificial waxes teeth are attached

22 / 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

23 / 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. Low stiffness

d. High stiffiness

24 / 60

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

a. Sulphide

b. Gamma I Phase

c. Gamma II Phase

d. Oxide

25 / 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

26 / 60

Minimum light exposure time for composite resins should be 😕

a. 10 sec

b. 5 sec

c. 20 sec

d. 40 sec

27 / 60

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

a. Subperiosteal

b. Transosteal frames

c. Endosseus implants

d. Intramucosal frames

28 / 60

The type of stress to which dental amalgam is more resistant to 😕

a. Compressive stress

b. Impact stress

c. Shear stress

d. Tensile stress

29 / 60

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

a. Decreases setting time

b. Depends on rate of mixing

c. Increases setting time

d. Does not alter setting time

30 / 60

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

a. It is more sensitive to oxygen inhibitors

b. It has more working time available

c. It has not more working time available

d. It takes more time for curing

31 / 60

In an alloy oxygen scavenger is 😕

a. Zinc

b. Palladium

c. Copper

d. Silver

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

d. It can hold more amount of impression material

33 / 60

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

a. Spermitic and bees wax

b. Carnauba and candellia

c. Paraffin and microcrystalline wax

d. Montan and Japan coco

34 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Is an irreversible hydrocolloid impression material

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

c. Will take up water and expand if kept wet

d. Will be shrink as a result of syneresis

35 / 60

A direct restorative material used frequently to restore a portion of a posterior tooth that is subject to large biting forces would possess which of the following properties ?

a. Thermal insulation

b. Ease of casting

c. Esthetics

d. High strength

36 / 60

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

a. Composite resin

b. Unfilled acrylic resin

c. Glass ionomer cement

d. Silicate cement

37 / 60

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

a. Amalgam

b. Composite resin

c. Metal

d. Gold alloy

38 / 60

Impression plaster is a 😕

a. Reversible impression material

b. Mucocompressive material

c. Thermoplastic material

d. Mucostatic material

39 / 60

All of the following are properties of Co-Cr-Ni wires except 😕

a. Their hardness is comparable to stainless steel

b. They can be heat treated

c. They have excellent tarnish and corrosion resistance

d. They cannot be soldered or welded

40 / 60

Which statements are true for bonding of amalgam to tooth structure ?

a. The use of amalgam bonding reduces marginal leakage of amalgam restorations.

b. The most effective bonding agents contain copalite.

c. The use of amalgam bonding restores the strength of the clinical crown to its original condition.

d. Shear bond strength using amalgam bonding to teeth in clinically proven to be as high as that for bonding composites to teeth.

41 / 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 can be employed as anterior filling materials

c. All of them are polymers

d. All of them are a result of secondary reaction

42 / 60

Inorganic phase in a composite matrix 😕

a. Increases coefficient of thermal expansion

b. Increases the polymerization shrinkage

c. Decreases the mechanical strength

d. Increases the mechanical strength

43 / 60

The main use of zinc oxide eugenol cement is 😕

a. Temporary restoration

b. Permanent restoration

c. Indirect pulp capping agent

d. Base

44 / 60

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

a. Toughness

b. Hardness

c. Brittleness

d. Springiness

45 / 60

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

a. 100 ng Hg/m3 of air

b. 0.05 mg Hg/m3 of air

c. All are corrects

d. 30 ng Hg/m3 of air

46 / 60

Commonly used filler in composite is 😕

a. Colloidal silica

b. Glass

c. Aluminum

d. Quartz

47 / 60

Greening effect of porcelain is due to 😕

a. Platinum

b. Silver

c. Palladium

d. Golde

48 / 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

49 / 60

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

a. Gold alloys

b. Composite resin

c. Amalgam

d. Ceramic

50 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 60 seconds

b. Phosphoric acid for 60 seconds

c. Polyacrylic acid for 10 seconds

d. Phosphoric acid for 10 seconds

51 / 60

Light source in the curing unit is usually 😕

a. Sun light

b. Infra red bulb

c. Ultraviolet light bulb

d. Tungsten halogen light bulb

52 / 60

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

a. Pheyl methacrylate

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

c. Poly (methyl methacrylate)

d. Polystyrene

53 / 60

Resistance of a liquid to motion is called 😕

a. Viscosity

b. Springiness

c. Creep

d. Diffusion

54 / 60

Metal has the following properties except 😕

a. Electroplated silver and copper are used in dies

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

c. Metal is any element that ionizes positively in solution

d. Pure metals are not useful in dentistry

55 / 60

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

a. Gypsum

b. Quartz

c. Silica

d. Water

56 / 60

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

a. Ag-Sn

b. Ag-Hg

c. Sn-Hg

d. Cu-Sn

57 / 60

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

a. Temperature of specificity

b. Heat temperature

c. Fusion temperature

d. Vapor temperature

58 / 60

Acrylic resins are used in which of the following ?

a. Anterior onlays

b. Denture bases

c. Ceramic ( porcelain )-fused-to-metal crowns

d. Posterior inlays

59 / 60

Which of the following initiator-accelerator systems is needed for a light-activated composite?

a. Organic acid-peroxide

b. Diketone-amine

c. Peroxide-amine

d. Organic acid-metal ion

60 / 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

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The average score is 42%

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