Biomaterial Test

5 votes, 5 avg

164

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Biomaterial Test

1 / 60

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

a. Amalgam

b. Metal

c. Gold alloy

d. Composite resin

2 / 60

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

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

b. Results in a marked expansion

c. Results in a sharp decrease in flow

d. Increases the setting time

3 / 60

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

a. Direct resin-filling material

b. Zinc phosphate

c. Amalgam

d. Silicate

4 / 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

5 / 60

Minimum light exposure time for composite resins should be 😕

a. 10 sec

b. 20 sec

c. 40 sec

d. 5 sec

6 / 60

Condensation of porcelain is done by all the methods except 😕

a. Spatulation method

b. Ceramming method

c. Brush addition technique

d. Vibration method

7 / 60

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

a. Organic acid-metal ion

b. Diketone-amine

c. Peroxide-amine

d. Organic acid-peroxide

8 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It is low in strength

b. Pure zinc has no application in dentistry

c. It is relatively soft and ductile

d. It does not oxidize

9 / 60

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

a. Toughness

b. Flexibility

c. Impact strength

d. Resilience

10 / 60

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

a. Subsequent oxidation of the tertiary amine

b. Increased solubility of the resin

c. Decreased polymerization of the resin

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

11 / 60

In dental plaster the main ingredient is 😕

a. Calcium sulfate dehydrate

b. Calcium sulfate hemihydarate

c. Calcium phosphate

d. Calcium anhydrate

12 / 60

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

a. Condensation silicone

b. Polyether

c. Polyvinyl siloxane

d. Polysulfied

13 / 60

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

a. 0.05 mg Hg/m3 of air

b. 100 ng Hg/m3 of air

c. 30 ng Hg/m3 of air

d. All are corrects

14 / 60

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

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

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

c. Microfilled

d. All are correct

15 / 60

The fluoride release from glass ionomer cement is 😕

a. 0.75 mg during the first week

b. 0.075 mg during the first month

c. 0.005 mg during the first week

d. 0.0005 mg during the first month

16 / 60

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

a. Is the oldest luting agent

b. Has an obtudant effect on the pulp

c. Is used as a permanent restorative material in adults

d. The least irritant to the pulp

17 / 60

The catalyst used for condensation silicones is 😕

a. Platinum

b. Stannous octoate

c. Lead dioxide

d. Oleic acid

18 / 60

A glaze is placed over the finished composite restoration to 😕

a. To reduce surface porosities

b. Create a rough surface that is less receptive to extrinsic stain and plaque retention

c. No provide a better peripheral seal

d. To change the shade

19 / 60

The main function of zinc in amalgam is 😕

a. To increase the longevity of amalgam after setting

b. To increase the shelf-life of an amalgam

c. To produce delayed expansion

d. To prevent the creep

20 / 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. Will take up water and expand if kept wet

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

21 / 60

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

a. 4 mm

b. 2 mm

c. 1 mm

d. 3 mm

22 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. Condense the unattacked gamma I particles

b. Condense the unattacked gamma II particles

c. To reduce gamma II particules

d. Condense the unattacked gamma particles

23 / 60

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

a. Sn-Hg

b. Ag-Hg

c. Ag-Sn

d. Cu-Sn

24 / 60

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

a. Artificial waxes teeth are attached

b. They are attached to natural teeth with cements,

c. Carbone steal

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

25 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Adhesive bonding between matrix and filler

b. Bonding between coupling agent and tooth structure

c. Bonding with tooth structure

d. Bonding between coupling agent and filler

26 / 60

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

a. Gold alloys

b. Composite restorative resins

c. Acrylic resin

d. Ceramic

27 / 60

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

a. Light from an argon laser will activate polymerization.

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

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

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

28 / 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 and zinc

d. The amount of copper

29 / 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

30 / 60

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

a. Utility wax

b. Carding wax

c. Beading wax

d. Boxing wax

31 / 60

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

a. Polyether

b. Polysulfides

c. Addition silicones

d. Condensation silicones

32 / 60

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

a. Impact stress

b. Compressive stress

c. Shear stress

d. Tensile stress

33 / 60

One of the disadvantages of using quartz as filler in restorative resin is 😕

a. It cause abrasion and wearing of opposing tooth surface

b. It cannot be polished

c. It has low affinity for resin matrix

d. It cannot be reduced to the size of microparticle composite

34 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Calcum hydroxide

b. Polycardoxylate

c. Zinc silicophoshpate

d. Zinc phosphate

35 / 60

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

a. Silicate cement

b. Composite resin

c. Glass ionomer cement

d. Unfilled acrylic resin

36 / 60

Ideal method firing of porcelain is by using 😕

a. Shorter firing at higher temperatures

b. Shorter firing at low temperatures

c. Longer firing at high temperatures

d. Longer firing at low temperatures

37 / 60

KHN of enamel is 😕

a. 600

b. 100

c. 300

d. 90-100

38 / 60

Regarding Knoop hardness number, which of the following material is closest to that of dentine (KHN 65) ?

a. Silicates

b. Pure gold

c. Amalgam

d. Composites

39 / 60

Setting of plaster of Paris is a result of 😕

a. Interaction between hemihydrates and water

b. Solubility difference between hemihydrates and dehydrate

c. Indirect interaction between hemihydrates

d. Loss of water from hemihydrates

40 / 60

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

a. Transosteal frames

b. Intramucosal frames

c. Endosseus implants

d. Subperiosteal

41 / 60

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

a. Low corrosion

b. Higher creep

c. High corrosion

d. Higher strength

42 / 60

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

a. It is a bio-inert material

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

c. This material in granular form and is difficult

d. It is produced in block or granula form

43 / 60

A potentially toxic element in base metal alloys is 😕

a. Beryllium

b. Molybdenum

c. Magnesium

d. Boron

44 / 60

In an alloy oxygen scavenger is 😕

a. Palladium

b. Zinc

c. Copper

d. Silver

45 / 60

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

a. Artificial acrylic teeth are attached

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

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

d. They are attached to natural teeth with cements,

46 / 60

Stearic acid in impression compound 😕

a. Reduces flow

b. Reduces plasticity

c. Increase setting time

d. Reduces brittleness

47 / 60

Chemically cured resin shrinks:?

a. On the surface only

b. Away from the light source

c. Towards the center of bulk of material

d. On the base only

48 / 60

The most commonly used implant type presently is 😕

a. Transosteal implant

b. Subperiosteal

c. Endosseous

d. Intramucosal implant

49 / 60

Resistance of a liquid to motion is called 😕

a. Diffusion

b. Creep

c. Springiness

d. Viscosity

50 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Surgical paste

b. Wash impression for edentulous patients

c. As interocclusal record material

d. Dual impression for Partially edentulous patients

51 / 60

Which of the following base is contraindicated for composites ?

a. Calcium hydroxide

b. Zinc phosphate

c. Zinc oxide eugenol

d. Glass ionomer cement

52 / 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. 0.04 mg Hg/m3 of air

b. 30 mg Hg/m3 of air

c. 100 mg Hg/m3 of air

d. 0.05 mg Hg/m3 of air

53 / 60

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

a. No Protein lysing effect

b. No antibacterial action

c. Low alkalinity

d. High alkalinity

54 / 60

Which of the following uses a hardened steel ball indenting tool ?

a. Brinell hardness test

b. Knoop hardness test

c. Rockwell hardness test

d. Vichers hardness test

55 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Low stiffness

b. Hydropholic in nature

c. High stiffiness

d. Can not be used as light cure material

56 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

a. When the material is glossy

b. Exactly after four minutes after kneading

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

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

57 / 60

Montan waxes have the following properties except 😕

a. Are mineral waxes

b. Obtained by extraction from lignite

c. Hard, brittle and lustrous

d. Have low melting points of 42oC

58 / 60

When the gold content of gold alloys increases 😕

a. The hardness decrease

b. The percentage elongation decrease

c. Ductility decrease

d. The corrosion resistance increases

59 / 60

The function of gum dammar in inlay wax is 😕

a. To improve smoothness of pattern

b. Less strength to wax

c. No smoothness of pattern

d. No resistance to carving

60 / 60

Elgiloy arch wire is 😕

a. Gold alloy

b. Cobalt-chromium-nickel alloy

c. β-titanium arch wire

d. Optical fiber arch wire

Your score is

The average score is 86%

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