Biomaterial Test

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Biomaterial Test

1 / 60

In deep caities, the resin which remains unpolymerized can cause 😕

a. Sagging of restoration

b. Secondary caries

c. Porosity in restoration

d. Pulp inflammation

2 / 60

In alginate impression the final gel is 😕

a. Sodium sulphate

b. Calcium alginate

c. Calcium sulphate

d. Sodium alginate

3 / 60

Working time of denture resin should be at least 😕

a. 10 minutes

b. 15 minutes

c. 5 minutes

d. 20 minutes

4 / 60

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

a. The amount of copper

b. The amount of copper and zinc

c. The amount of copper and tin

d. The amount of copper and silver

5 / 60

A potentially toxic element in base metal alloys is 😕

a. Molybdenum

b. Beryllium

c. Boron

d. Magnesium

6 / 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. Radiopaque

c. They are radiolucent.

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

7 / 60

Gold with high percentage elongation is best for 😕

a. To remove metallic oxide

b. To revert sagging during firing

c. Increase the bond strength

d. To improve the castability

8 / 60

A portion of a posterior tooth that is subject to high biting forces would likely be restored with which of the following ?

a. Composite resin

b. Glass ionomer

c. Amalgam

d. Acrylic resin

9 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Polycardoxylate

b. Zinc silicophoshpate

c. Calcum hydroxide

d. Zinc phosphate

10 / 60

Thermal conductivity is proportional to 😕

a. Area of conduction

b. Hardness of metal

c. Type of metal

d. Fusion temperature

11 / 60

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

a. Silicate cement

b. Glass ionomer cement

c. Unfilled acrylic resin

d. Composite resin

12 / 60

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

a. Polysulfides

b. Condensation silicones

c. Polyether

d. Addition silicones

13 / 60

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

a. Gold

b. Glass ionomer

c. Ceramic

d. Waxe

14 / 60

In an alloy oxygen scavenger is 😕

a. Zinc

b. Silver

c. Copper

d. Palladium

15 / 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 takes more time for curing

d. It has not more working time available

16 / 60

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

a. Addition silicone

b. Polyether

c. Polysulfide

d. Condensation silicone

17 / 60

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

a. Polysulfied

b. Polyether

c. Condensation silicone

d. Polyvinyl siloxane

18 / 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 does not oxidize

d. It is relatively soft and ductile

19 / 60

Potato starch is contained in which impression material ?

a. Agar agar

b. Potassium sulfate

c. Impression compound

d. Impression plaster

20 / 60

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

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

b. A cover over the mixing arms on a triturator

c. Mixing in a mortar and pestle

d. Triturating precapsulated alloy and mercury

21 / 60

The main function of zinc in amalgam is 😕

a. To prevent the creep

b. To increase the longevity of amalgam after setting

c. To increase the shelf-life of an amalgam

d. To produce delayed expansion

22 / 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 between coupling agent and filler

d. Bonding with tooth structure

23 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Polyvinyl siloxane

b. Zinc oxide eugenol impression paste

c. Alginate

d. Polyether

24 / 60

Adhesion in composites is due to 😕

a. Presence of smear layer

b. True chemical bonding to tooth structure

c. Mechanical interlocking

d. Cohesion

25 / 60

Elgiloy arch wire is 😕

a. Gold alloy

b. Optical fiber arch wire

c. β-titanium arch wire

d. Cobalt-chromium-nickel alloy

26 / 60

Which of the following statements about laboratory composites are true ?

a. Fiber reinforcement increases their strength but decrease their rigidity.

b. Restorations prepared from laboratory composites typically are cemented with zinc phosphate cement.

c. Bridge prepared from laboratory composites require a metal substructure.

d. Curing using light, heat, and pressure increase the wear resistance.

27 / 60

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

a. Has an obtudant effect on the pulp

b. The least irritant to the pulp

c. Is used as a permanent restorative material in adults

d. Is the oldest luting agent

28 / 60

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

a. Gamma II Phase

b. Oxide

c. Gamma I Phase

d. Sulphide

29 / 60

The main advantage of composites compared to silicates cement is 😕

a. High modulus of resilience

b. Color matching with the tooth structure is excellent

c. Practically insoluble in oral fluids

d. Coefficient of thermal expansion close to tooth structure

30 / 60

The catalyst used for condensation silicones is 😕

a. Lead dioxide

b. Oleic acid

c. Stannous octoate

d. Platinum

31 / 60

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

a. Barium glass

b. Quartz

c. Colloidal silica

d. Lithium aluminum silicate

32 / 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

33 / 60

A measure of ductility of a material is referred to as 😕

a. Flexibility

b. Percentage elongation

c. Yield strength

d. Proportional limit

34 / 60

The cracks formed on the ceramic during cooling because 😕

a. The inner layer cools more rapidly than the outer layer

b. The outer layer cools more rapidly than the interior

c. Due to external forces

d. The cooling of the outer and the inner layer occurs at the same rate

35 / 60

Porcelain denture teeth 😕

a. Have higher coefficient of thermal expansion than resin teeth

b. Are easy to grind and polish

c. Have decreased abrasion resistance than dentin

d. Are more resistant of abrasion than gold

36 / 60

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

a. Gold alloy

b. Amalgam

c. Silver alloys

d. Ceramic

37 / 60

Noble metal alloys are classified according to their 😕

a. Castability

b. Dental function

c. Malleability

d. Melting temperature

38 / 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. 100 ng Hg/m3 of air

c. 30 ng Hg/m3 of air

d. 0.05 mg Hg/m3 of air

39 / 60

KHN of enamel is 😕

a. 90-100

b. 600

c. 300

d. 100

40 / 60

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

a. Transosteal frames

b. Subperiosteal

c. Endosseus implants

d. Intramucosal frames

41 / 60

Glass ionomer cenment is not recommended for 😕

a. Class IV resoration

b. Class III restoration

c. Class I restoration

d. Class V restoration

42 / 60

Hand instruments for composites are made of 😕

a. Stainless steel

b. Teflon-coated metal

c. Carbon steel

d. Titanium

43 / 60

Porosity in denture base resins can be due to 😕

a. Adequate mixing of liquid and powder components

b. Excess heating of resin above its boiling point

c. Well flasking of wax pattern

d. Applying sufficient pressure during polymerization

44 / 60

Nickel in base metal alloys increase its 😕

a. S Ductility

b. Hardness and fusion temperature

c. Modulus of elasticity

d. Strength

45 / 60

Inorganic phase in a composite matrix 😕

a. Increases coefficient of thermal expansion

b. Increases the mechanical strength

c. Decreases the mechanical strength

d. Increases the polymerization shrinkage

46 / 60

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

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

b. Artificial waxes teeth are attached

c. Carbone steal

d. They are attached to natural teeth with cements,

47 / 60

Commonly used coloring agent in impression plaster is 😕

a. Metallic oxide

b. Congo red

c. Alizarin red

d. Indigo dye

48 / 60

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

a. No evolution of any byproduct under all circumstances

b. Undetectable distortion on removal

c. Can be used in automixing devices

d. Dimensionally stable even after 1 week

49 / 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 thermal insulation

d. Provide electrical insulation

50 / 60

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

a. They cannot be soldered or welded

b. Their hardness is comparable to stainless steel

c. They have excellent tarnish and corrosion resistance

d. They can be heat treated

51 / 60

Which has the highest viscoelastic property and requires more time to recover from deformation ?

a. Polyether

b. Addition silicone

c. Condensation silicone

d. Polysulfide

52 / 60

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

a. Gold alloys

b. Ceramic

c. Amalgam

d. Composite resin

53 / 60

The most commonly used implant type presently is 😕

a. Endosseous

b. Transosteal implant

c. Subperiosteal

d. Intramucosal implant

54 / 60

Clinical significance of smear layer :

a. Improve the strength of the composite

b. Provides calcium for adhesion of composites

c. Bonded to tooth structure and prevents composite adhesion

d. Increases the bonding action of the bonding agent

55 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Conserves the material

b. Decreases air voids in the restoration

c. Increases surface smoothness

d. Increases strength and abrasive resistance

56 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Facilitate mechanical bonding

b. Provide more strenght

c. Create tags

d. Remove smear layer

57 / 60

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

a. Zinc phosphate

b. Silicate

c. Amalgam

d. Direct resin-filling material

58 / 60

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

a. Addition silicones

b. Condensation silicones

c. Polyethers

d. Polysulfides

59 / 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

60 / 60

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

a. Shear stress

b. Tensile stress

c. Impact stress

d. Compressive stress

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