Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

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

b. It cause abrasion and wearing of opposing tooth surface

c. It has low affinity for resin matrix

d. It cannot be polished

2 / 60

Commonly used coloring agent in impression plaster is 😕

a. Metallic oxide

b. Congo red

c. Indigo dye

d. Alizarin red

3 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Bonding with tooth structure

b. Bonding between coupling agent and filler

c. Adhesive bonding between matrix and filler

d. Bonding between coupling agent and tooth structure

4 / 60

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

a. Can be used in automixing devices

b. Undetectable distortion on removal

c. Dimensionally stable even after 1 week

d. No evolution of any byproduct under all circumstances

5 / 60

Which of the following is the best choice of restorative material to achieve moderate to high strength, fluorite release, and esthetics ?

a. Hybrid ionomer

b. Composite

c. Compomer

d. Glass ionomer

6 / 60

Nickel in base metal alloys increase its 😕

a. S Ductility

b. Modulus of elasticity

c. Hardness and fusion temperature

d. Strength

7 / 60

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

a. Increases setting time

b. Decreases setting time

c. Does not alter setting time

d. Depends on rate of mixing

8 / 60

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

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

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

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

d. Light from an argon laser will activate polymerization.

9 / 60

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

a. They can be heat treated

b. They cannot be soldered or welded

c. They have excellent tarnish and corrosion resistance

d. Their hardness is comparable to stainless steel

10 / 60

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

a. Is the oldest luting agent

b. Is used as a permanent restorative material in adults

c. Has an obtudant effect on the pulp

d. The least irritant to the pulp

11 / 60

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

a. Silver alloys

b. Amalgam

c. Gold alloy

d. Ceramic

12 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Ferric oxide

b. Cobalt oxide

c. Chromium oxide

d. Chromium carbide

13 / 60

Commonly used viscosity controller in composites is 😕

a. Methyl methacrylate

b. Polyurethanes

c. Bis-GAM

d. TEG-DMA

14 / 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 lower natural teeth with cements,

c. They are attached to natural teeth with cements,

d. Artificial acrylic teeth are attached

15 / 60

Glass ionomer cenment is not recommended for 😕

a. Class I restoration

b. Class III restoration

c. Class V restoration

d. Class IV resoration

16 / 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. 0.05 mg Hg/m3 of air

d. 100 mg Hg/m3 of air

17 / 60

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

a. Oxide

b. Gamma I Phase

c. Sulphide

d. Gamma II Phase

18 / 60

For proper wetting, contact angle should be ideally 😕

a. 600

b. 450

c. 00

d. 900

19 / 60

Gold with high percentage elongation is best for 😕

a. Increase the bond strength

b. To remove metallic oxide

c. To revert sagging during firing

d. To improve the castability

20 / 60

A glaze is placed over the finished composite restoration to 😕

a. No provide a better peripheral seal

b. To reduce surface porosities

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

d. To change the shade

21 / 60

Resistance of a liquid to motion is called 😕

a. Springiness

b. Creep

c. Diffusion

d. Viscosity

22 / 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

23 / 60

Potato starch is contained in which impression material ?

a. Potassium sulfate

b. Agar agar

c. Impression compound

d. Impression plaster

24 / 60

Amalgam is less prone to corrosion 😕

a. If it contains zinc

b. If devoid of the gamma 2 phase

c. If it contains 25-27% of tin

d. If it contains 4-6% of copper

25 / 60

The desirable quality of porcelain is 😕

a. Translucency

b. Thermal expansion

c. Toughness without brittleness

d. Requirement of color

26 / 60

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

a. Composite restorative resins

b. Has the toxic properties of unreacted mercury

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

d. Is combined primarily with silver

27 / 60

Porcelain denture teeth 😕

a. Are easy to grind and polish

b. Have decreased abrasion resistance than dentin

c. Have higher coefficient of thermal expansion than resin teeth

d. Are more resistant of abrasion than gold

28 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Cost factor is high

b. Maximum details are not produced

c. Difficult to manipulate

d. Bond between agar and alginate is not very strong

29 / 60

Working time of denture resin should be at least 😕

a. 10 minutes

b. 20 minutes

c. 5 minutes

d. 15 minutes

30 / 60

Wet porcelain is condensed properly before firing to enhance all the properties except : ?

a. Reduce porosity

b. Reduce firing shrinkage

c. increase strength

d. Reduce brittleness

31 / 60

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

a. Biocompatibility

b. Dimensional stability

c. Adhesion

d. Flow

32 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Decreases air voids in the restoration

b. Conserves the material

c. Increases strength and abrasive resistance

d. Increases surface smoothness

33 / 60

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

a. They are attached to natural teeth with cements,

b. Carbone steal

c. Artificial waxes teeth are attached

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

34 / 60

Which of the following statements about compomers are true ?

a. They are two-paste systems that self-cure within 2 to 3 minutes.

b. They also are know as GIC

c. Because of their resin content, they require a bonding agent for adhesion to tooth structure.

d. They typically are recommended for class II restorations.

35 / 60

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

a. Amalgam

b. Ceramic

c. Composite resin

d. Gold alloys

36 / 60

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

a. Condensation silicones

b. Polysulfides

c. Addition silicones

d. Polyethers

37 / 60

Adhesion in composites is due to 😕

a. Cohesion

b. Presence of smear layer

c. Mechanical interlocking

d. True chemical bonding to tooth structure

38 / 60

Greening effect of porcelain is due to 😕

a. Silver

b. Platinum

c. Palladium

d. Golde

39 / 60

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

a. Sn-Hg

b. Cu-Sn

c. Ag-Hg

d. Ag-Su

40 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 45-600C

b. Far below the oral temperature

c. 37-450C

d. 100C higher than mouth temperature

41 / 60

Minimal thickness of base for adequate thermal insulation is 😕

a. 0.5 mm

b. 1 mm

c. 0.75 mm

d. 2 mm

42 / 60

Impression plaster is a 😕

a. Thermoplastic material

b. Reversible impression material

c. Mucostatic material

d. Mucocompressive material

43 / 60

Which of the following composite is recommended for non stress bearing anterior restoration ?

a. Hybrid composites

b. Conventional composites

c. Microfilled composites

d. Small particles

44 / 60

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

a. Poly (methyl methacrylate)

b. Pheyl methacrylate

c. Polystyrene

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

45 / 60

In a porcelain fused to metal restoration, when the coefficient of thermal expansion of metal and porcelain are different 😕

a. Porcelain will wear off

b. Porcelain will crack on cooling

c. Porcelain will not bond with metal

d. Porcelain will provide good shade

46 / 60

The byproduct in condensation silicones is 😕

a. Methyl alcohol

b. Propyl alcohol

c. Ethyl alcohol

d. Butyl alcohol

47 / 60

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

a. No antibacterial action

b. Low alkalinity

c. No Protein lysing effect

d. High alkalinity

48 / 60

Which of the following statements about adhesion of composite restorations to tooth structure are true ?

a. Bonding is achieved to enamel by application of an acid etchant followed by application of a bonding agent and then the composites resin.

b. The bonding agent forms a micromechanical bond with enamel but a chemical bond with dentin.

c. The bonding agent forms a hybrid layer with enamel.

d. Most bonding agent bond more effectively to a dry tooth surface.

49 / 60

Which of the following materials are used for dental implants ?

a. Titanium

b. Metal alloys

c. Cobalt and chromium alloys

d. Gold alloys

50 / 60

The physical properties most desirable in set amalgam are which of the following ?

a. Higher strength, high creep, high corrosion

b. Higher strength, low creep, low corrosion

c. Higher strength, high creep, low corrosion

d. Low strength, low creep, low corrosion

51 / 60

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

a. Composites

b. Pure gold

c. Amalgam

d. Silicates

52 / 60

Which one of the following is not true about high-copper dental amalgam restorations ?

a. Produce excessive creep

b. Contain both Sn and Ag in the composition as well

c. Better corrosion resistance than low-copper dental amalgams

d. Restorations are more brittle than low-copper versions

53 / 60

KHN of enamel is 😕

a. 90-100

b. 100

c. 600

d. 300

54 / 60

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

a. Flexibility

b. Toughness

c. Impact strength

d. Resilience

55 / 60

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

a. Vacuum up a spill immediately

b. Sterilize amalgam scrap

c. Avoid polishing amalgams

d. Avoid touching freshly mixed amalgam

56 / 60

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

a. Resilience

b. Toughness

c. Modulus of elasticity

d. Flexibility

57 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Polyether

b. Polyvinyl siloxane

c. Alginate

d. Zinc oxide eugenol impression paste

58 / 60

Alginate impression material deteriorates rapidly at 😕

a. Elevated temperature

b. Low temperature

c. Normal room temperature

d. Temperature does not cause any change in shelf-life

59 / 60

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

a. Mixing in a mortar and pestle

b. Triturating precapsulated alloy and mercury

c. A cover over the mixing arms on a triturator

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

60 / 60

Setting time of alginate can be better controlled by 😕

a. Mixing time

b. Chemical accelerators and retarders

c. Temperature of water used of mixing

d. Changing water: powder ratio

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The average score is 22%

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