Biomaterial Test

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Biomaterial Test

1 / 60

Proportional limit is defined as :

a. A deformation resulting from an applied load

b. The maximum force required to cause a structure to break

c. The stress/strain ratio within the elastic limit in a structure

d. The maximum stress that can be induced without permanent deformation

2 / 60

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

a. Gold alloy

b. Silver alloys

c. Amalgam

d. Ceramic

3 / 60

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

a. Polyether

b. Addition silicone

c. Polysulfide

d. Condensation silicone

4 / 60

Greening effect of porcelain is due to 😕

a. Golde

b. Silver

c. Platinum

d. Palladium

5 / 60

Porcelain denture teeth 😕

a. Have higher coefficient of thermal expansion than resin teeth

b. Are more resistant of abrasion than gold

c. Have decreased abrasion resistance than dentin

d. Are easy to grind and polish

6 / 60

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

a. Avoid touching freshly mixed amalgam

b. Avoid polishing amalgams

c. Vacuum up a spill immediately

d. Sterilize amalgam scrap

7 / 60

Gold with high percentage elongation is best for 😕

a. To improve the castability

b. To revert sagging during firing

c. To remove metallic oxide

d. Increase the bond strength

8 / 60

Silver in the set amalgam alloy tends to have the following effect 😕

a. Produces contraction

b. Decreases ductility

c. Hydrolyzes the water if contaminated

d. Decreases the setting time

9 / 60

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

a. Hybrid composites

b. Microfilled composites

c. Conventional composites

d. Small particles

10 / 60

The following statements about dental porcelains are true except 😕

a. Crystalline nature

b. It is brittle in nature

c. Undergoes discoloration

d. Undergoes firing shrinkage

11 / 60

Noble metal alloys are classified according to their 😕

a. Dental function

b. Malleability

c. Melting temperature

d. Castability

12 / 60

In alginate impression the final gel is 😕

a. Calcium alginate

b. Sodium alginate

c. Calcium sulphate

d. Sodium sulphate

13 / 60

In a porcelain fused to metal restoration, the porcelain is-bonded to metal by 😕

a. Hight ductility of metal

b. High malleafility of metal

c. Chemical bonding

d. Chemico-mechenical bonding

14 / 60

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

a. 1 mm

b. 3 mm

c. 2 mm

d. 4 mm

15 / 60

Hydrocolloid impression should be removed from the mouth with a sharp jerk because 😕

a. Faster rate of removal increases the yield strength

b. The brush heap structure of a gel responds more favorably to a sudden force

c. It is the easiest method of removal

d. It decreases the time for syneresis to occur

16 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can not lead to fungal growth

b. It can be cleaned properly

c. It can not lead to cleaned property

d. It has not to be changed over a period of time

17 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Toluidine

b. Benzoyl methyl ether

c. Camphoroquinone

d. Bis-phenol-A

18 / 60

For proper wetting, contact angle should be ideally 😕

a. 00

b. 450

c. 900

d. 600

19 / 60

In UV curing system the activator employed is 😕

a. Benzoin methyl ether

b. Methyl methacrylate

c. Dibutyl phthalate

d. Hydroquinone

20 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To reduce discoloration

b. To reduce gamma II particule

c. Reduce surface microporosities

d. To prevent recurrent carries

21 / 60

The main use of zinc oxide eugenol cement is 😕

a. Indirect pulp capping agent

b. Temporary restoration

c. Permanent restoration

d. Base

22 / 60

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

a. Composite resin

b. Amalgam

c. Metal

d. Gold alloy

23 / 60

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

a. Dimensionally stable even after 1 week

b. Undetectable distortion on removal

c. No evolution of any byproduct under all circumstances

d. Can be used in automixing devices

24 / 60

A small portion of an anterior tooth would most likely be restored with which of the following ?

a. Composite resin

b. Gold alloy

c. Porcelain

d. Amalgam

25 / 60

The temperature at which a solid changes into liquid is called 😕

a. Fusion temperature

b. Latent heat

c. Specific temperature

d. Temperature of vaporization

26 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. Under low temperature

b. Under compression

c. Several times in air

d. After metal is tempered

27 / 60

Commonly used coloring agent in impression plaster is 😕

a. Metallic oxide

b. Indigo dye

c. Alizarin red

d. Congo red

28 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Phosphoric acid for 60 seconds

b. Phosphoric acid for 10 seconds

c. Polyacrylic acid for 10 seconds

d. Polyacrylic acid for 60 seconds

29 / 60

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

a. Silicate

b. Amalgam

c. Zinc phosphate

d. Direct resin-filling material

30 / 60

Condensation of porcelain is done by all the methods except 😕

a. Ceramming method

b. Spatulation method

c. Vibration method

d. Brush addition technique

31 / 60

Light source in the curing unit is usually 😕

a. Ultraviolet light bulb

b. Tungsten halogen light bulb

c. Infra red bulb

d. Sun light

32 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Wash impression for edentulous patients

b. As interocclusal record material

c. Surgical paste

d. Dual impression for Partially edentulous patients

33 / 60

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

a. Ag-Su

b. Cu-Sn

c. Sn-Hg

d. Ag-Hg

34 / 60

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

a. They cannot be soldered or welded

b. They have excellent tarnish and corrosion resistance

c. They can be heat treated

d. Their hardness is comparable to stainless steel

35 / 60

Chemically cured resin shrinks:?

a. On the surface only

b. On the base only

c. Towards the center of bulk of material

d. Away from the light source

36 / 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. Mixing in a mortar and pestle

c. Triturating precapsulated alloy and mercury

d. A cover over the mixing arms on a triturator

37 / 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

38 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Polycardoxylate

b. Zinc silicophoshpate

c. Calcum hydroxide

d. Zinc phosphate

39 / 60

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

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

b. The most effective bonding agents contain copalite.

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

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

40 / 60

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

a. Higher creep

b. High corrosion

c. Low corrosion

d. Higher strength

41 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Silver

b. Copper

c. Cobalt

d. Nickel

42 / 60

Potato starch is contained in which impression material ?

a. Impression plaster

b. Impression compound

c. Agar agar

d. Potassium sulfate

43 / 60

Materials having coefficient of thermal expansion close to the tooth structure 😕

a. Silicate cement

b. Amalgam

c. Unfilled

d. Glass ionomer cement

44 / 60

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

a. Polyethers

b. Polysulfides

c. Addition silicones

d. Condensation silicones

45 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It is harder and has less flow

b. It is sticky

c. It provides luster to the pattern

d. It has low melting temperature

46 / 60

Working time of denture resin should be at least 😕

a. 15 minutes

b. 10 minutes

c. 20 minutes

d. 5 minutes

47 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Deflasking

b. Polishing

c. Packing

d. Curing

48 / 60

Stearic acid in impression compound 😕

a. Reduces flow

b. Increase setting time

c. Reduces plasticity

d. Reduces brittleness

49 / 60

Resistance of a liquid to motion is called 😕

a. Springiness

b. Viscosity

c. Diffusion

d. Creep

50 / 60

Which of the following statements about compomers are true ?

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

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

c. They also are know as GIC

d. They typically are recommended for class II restorations.

51 / 60

Calcium hydroxide is used for 😕

a. Reinforce the restoration

b. To prevent recurrent caries

c. Pulp capping

d. Reduce maginal leakage

52 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Is an irreversible hydrocolloid impression material

b. Will take up water and expand if kept wet

c. Will be shrink as a result of syneresis

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

53 / 60

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

a. Intramucosal frames

b. Transosteal frames

c. Subperiosteal

d. Endosseus implants

54 / 60

Metal has the following properties except 😕

a. Metal is any element that ionizes positively in solution

b. Electroplated silver and copper are used in dies

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

d. Pure metals are not useful in dentistry

55 / 60

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

a. It takes more time for curing

b. It has not more working time available

c. It is more sensitive to oxygen inhibitors

d. It has more working time available

56 / 60

The physical property measured in terms of the deformation of the structure per until dimensions is ?

a. Stress

b. Amorphous material

c. Space lattice

d. Strain

57 / 60

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

a. Silicates

b. Pure gold

c. Composites

d. Amalgam

58 / 60

KHN of enamel is 😕

a. 100

b. 90-100

c. 600

d. 300

59 / 60

The most commonly used implant type presently is 😕

a. Subperiosteal

b. Endosseous

c. Transosteal implant

d. Intramucosal implant

60 / 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

Your score is

The average score is 60%

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