Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

a. Requires more mercury for trituration

b. Requires less amalgamation time

c. Have longer setting time

d. Requires higher forces of condensation

2 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Toluidine

b. Bis-phenol-A

c. Camphoroquinone

d. Benzoyl methyl ether

3 / 60

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

a. Decreased polymerization of the resin

b. Subsequent oxidation of the tertiary amine

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

d. Increased solubility of the resin

4 / 60

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

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

b. Should bond with dental porcelain

c. Should be brittle

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

5 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

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

b. Exactly after four minutes after kneading

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

d. When the material is glossy

6 / 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

7 / 60

For luting purpose, the film thickness should be 😕

a. minimum 50 μm

b. ideally 100 μm

c. up to 75 μm

d. 25 μm or less

8 / 60

Greening effect of porcelain is due to 😕

a. Platinum

b. Palladium

c. Silver

d. Golde

9 / 60

In an alloy oxygen scavenger is 😕

a. Silver

b. Copper

c. Zinc

d. Palladium

10 / 60

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

a. Higher creep

b. Higher strength

c. High corrosion

d. Low corrosion

11 / 60

Potato starch is contained in which impression material ?

a. Potassium sulfate

b. Impression compound

c. Agar agar

d. Impression plaster

12 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Polyether

b. Zinc oxide eugenol impression paste

c. Polyvinyl siloxane

d. Alginate

13 / 60

Silver has all the following characteristics except 😕

a. Addition of palladium to silver increases corrosion

b. Whitens when added to alloys

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

d. Silver points serve as a root canal filling material

14 / 60

One of the following statements which one is incorrect regarding addition silicones 😕

a. Undetectable distortion on removal

b. No evolution of any byproduct under all circumstances

c. Can be used in automixing devices

d. Dimensionally stable even after 1 week

15 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Phosphoric acid for 60 seconds

b. Polyacrylic acid for 10 seconds

c. Polyacrylic acid for 60 seconds

d. Phosphoric acid for 10 seconds

16 / 60

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

a. Boxing wax

b. Carding wax

c. Utility wax

d. Beading wax

17 / 60

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

a. Ag-Su

b. Ag-Hg

c. Sn-Hg

d. Cu-Sn

18 / 60

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

a. Has the toxic properties of unreacted mercury

b. Is combined primarily with silver

c. Composite restorative resins

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

19 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To prevent recurrent carries

b. To reduce discoloration

c. To reduce gamma II particule

d. Reduce surface microporosities

20 / 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. Oxide

d. Gamma II Phase

21 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. Pure zinc has no application in dentistry

b. It is low in strength

c. It does not oxidize

d. It is relatively soft and ductile

22 / 60

The strain at which the plastic strain develops may be represented by 😕

a. Elastic limit, yield strength, proportional limit

b. Toughness, rigidity, resilience

c. Yield strength, tensile strength, toughness

d. Elastic limit, modulus of elasticity, tensile strength

23 / 60

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

a. Floor carpeting

b. Baseboard heating

c. Wall carpeting

d. Amalgam scrap stored in a closed container

24 / 60

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

a. All are corrects

b. 0.05 mg Hg/m3 of air

c. 100 ng Hg/m3 of air

d. 30 ng Hg/m3 of air

25 / 60

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

a. They are attached to upper natural teeth with cements,

b. They are attached to natural teeth with cements,

c. Artificial acrylic teeth are attached

d. They are attached to lower natural teeth with cements,

26 / 60

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

a. Impact strength

b. Resilience

c. Toughness

d. Flexibility

27 / 60

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

a. Avoid touching freshly mixed amalgam

b. Sterilize amalgam scrap

c. Vacuum up a spill immediately

d. Avoid polishing amalgams

28 / 60

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

a. Flexibility

b. Resilience

c. Toughness

d. Modulus of elasticity

29 / 60

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

a. Montan and Japan coco

b. Carnauba and candellia

c. Spermitic and bees wax

d. Paraffin and microcrystalline wax

30 / 60

When the gold content of gold alloys increases 😕

a. The percentage elongation decrease

b. The hardness decrease

c. The corrosion resistance increases

d. Ductility decrease

31 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Is an irreversible hydrocolloid impression material

b. Will be shrink as a result of syneresis

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

d. Will take up water and expand if kept wet

32 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 37-450C

b. 45-600C

c. Far below the oral temperature

d. 100C higher than mouth temperature

33 / 60

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

a. Sn-Hg

b. Ag-Sn

c. Ag-Hg

d. Cu-Sn

34 / 60

The main advantage of composites compared to silicates cement is 😕

a. Practically insoluble in oral fluids

b. Color matching with the tooth structure is excellent

c. High modulus of resilience

d. Coefficient of thermal expansion close to tooth structure

35 / 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

36 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Wash impression for edentulous patients

b. Dual impression for Partially edentulous patients

c. Surgical paste

d. As interocclusal record material

37 / 60

The fluoride release from glass ionomer cement is 😕

a. 0.0005 mg during the first month

b. 0.075 mg during the first month

c. 0.75 mg during the first week

d. 0.005 mg during the first week

38 / 60

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

a. Organic acid-peroxide

b. Peroxide-amine

c. Diketone-amine

d. Organic acid-metal ion

39 / 60

The most commonly used implant type presently is 😕

a. Endosseous

b. Transosteal implant

c. Intramucosal implant

d. Subperiosteal

40 / 60

The greatest amount of dimensional change after setting is exhibited by 😕

a. Condensation silicones

b. Polyethers

c. Addition silicones

d. Polysulfides

41 / 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. 100 mg Hg/m3 of air

d. 0.05 mg Hg/m3 of air

42 / 60

Nickel sensitivity in the general population is 😕

a. 1% in the overall population

b. 11% for women

c. 3% for women

d. 3% for men

43 / 60

Which of the following properties would be of least importance, when selecting an impression material ?

a. Flow

b. Biocompatibility

c. Dimensional stability

d. Adhesion

44 / 60

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

a. Ag-Hg

b. Cu-Sn

c. Sn-Hg

d. Ag-Sn

45 / 60

Chemically cured resin shrinks:?

a. On the base only

b. Towards the center of bulk of material

c. Away from the light source

d. On the surface only

46 / 60

For proper wetting, contact angle should be ideally 😕

a. 600

b. 00

c. 450

d. 900

47 / 60

The restorative material used to restore a small portion of an anterior tooth should have which of the following properties ?

a. Amalgam

b. High strength

c. Esthetics

d. Ease of casting

48 / 60

Inorganic phase in a composite matrix 😕

a. Decreases the mechanical strength

b. Increases coefficient of thermal expansion

c. Increases the polymerization shrinkage

d. Increases the mechanical strength

49 / 60

Wrought metal 😕

a. Cannot be rendered corrosion resistant

b. Can be formed by working on a cast metal

c. Cannot be heat treated

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

50 / 60

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

a. Biocompatibility

b. Iatrogenesis

c. Teratogenesis

d. Carcinogenesis

51 / 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

52 / 60

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

a. An undertriturated mass is crumbly and dull.

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

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

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

53 / 60

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

a. Heat temperature

b. Vapor temperature

c. Fusion temperature

d. Temperature of specificity

54 / 60

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

a. Titanium-molybdenum-vanadium alloy

b. Platinum-aluminum-vanadium alloy

c. Titanium-platinum-aluminum alloy

d. Titanium-aluminum-vanadium alloy

55 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Get a smooth surface

b. Increase strength

c. Reduce porosity

d. Regulate the setting time

56 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Tensile strength increases

b. Compressive strength decreases

c. Corrosion increases

d. Corrosion decreases

57 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Prolonged healing time

b. Presence of fibrous tissue

c. Lesser bony apposition

d. Greater bony opposition

58 / 60

Porcelain denture teeth 😕

a. Are more resistant of abrasion than gold

b. Are easy to grind and polish

c. Have higher coefficient of thermal expansion than resin teeth

d. Have decreased abrasion resistance than dentin

59 / 60

Porosity in denture base resins can be due to 😕

a. Applying sufficient pressure during polymerization

b. Adequate mixing of liquid and powder components

c. Excess heating of resin above its boiling point

d. Well flasking of wax pattern

60 / 60

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

a. High alkalinity

b. No Protein lysing effect

c. Low alkalinity

d. No antibacterial action

Your score is

The average score is 29%

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