Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

a. Cu-Sn

b. Sn-Hg

c. Ag-Su

d. Ag-Hg

2 / 60

Hand instruments for composites are made of 😕

a. Teflon-coated metal

b. Carbon steel

c. Stainless steel

d. Titanium

3 / 60

The tendency of stainless steel to break under repeated condition of cyclic stressing below the ultimate strength is 😕

a. Resilience

b. Fatigue

c. Creep

d. Ductility

4 / 60

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

a. Ceramic

b. Glass ionomer

c. Gold

d. Waxe

5 / 60

Which of the following statements apply to the packable composites ?

a. They are radiolucent.

b. Their depth of cure allows bulk polymerization, which has been shown to be clinically effective.

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

d. Radiopaque

6 / 60

Which of the following is a measure of resistance to fracture ?

a. Hardness

b. Brittleness

c. Toughness

d. Springiness

7 / 60

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

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

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

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

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

8 / 60

Oxalates, carbonates, potassium, trisodium phosphates are added to alginate as 😕

a. Reactors

b. Retarders

c. Accelerators

d. Fillers

9 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To prevent recurrent carries

b. To reduce discoloration

c. Reduce surface microporosities

d. To reduce gamma II particule

10 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Prolonged healing time

b. Greater bony opposition

c. Presence of fibrous tissue

d. Lesser bony apposition

11 / 60

Calcium hydroxide is used for 😕

a. Reduce maginal leakage

b. Reinforce the restoration

c. Pulp capping

d. To prevent recurrent caries

12 / 60

Proportional limit is defined as :

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

b. A deformation resulting from an applied load

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

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

13 / 60

A cavity varnish used for lining the preparation for a dental amalgam restoration will :

a. Provide thermal insulation

b. Provide electrical insulation

c. Provide strength of amalgam

d. Reduce early marginal leakage tooth structure

14 / 60

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

a. Unfilled acrylic resin

b. Composite resin

c. Glass ionomer cement

d. Silicate cement

15 / 60

Impression plaster is a 😕

a. Thermoplastic material

b. Mucocompressive material

c. Mucostatic material

d. Reversible impression material

16 / 60

Biting force in the molar region ranges from 😕

a. 1000-1300 N

b. 400-890 N

c. 600-1000 N

d. 900-1000 N

17 / 60

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

a. Rockwell hardness test

b. Knoop hardness test

c. Brinell hardness test

d. Vichers hardness test

18 / 60

The appropriate proportion of polymer to monomer component of dental resin by volume is generally 😕

a. 1:2

b. 3:1

c. 1:3

d. 2:1

19 / 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

20 / 60

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

a. Organic acid-peroxide

b. Peroxide-amine

c. Organic acid-metal ion

d. Diketone-amine

21 / 60

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

a. Latent heat

b. Fusion temperature

c. Temperature of vaporization

d. Specific temperature

22 / 60

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

a. Amorphous material

b. Strain

c. Stress

d. Space lattice

23 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Nickel

b. Cobalt

c. Silver

d. Copper

24 / 60

The common characteristic for pit and fissure sealant composite resins, acrylic appliances and elastomeric impression materials is :

a. All of them should be heated before using

b. All of them are polymers

c. All of them are a result of secondary reaction

d. All of them can be employed as anterior filling materials

25 / 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. 0.05 mg Hg/m3 of air

b. 0.04 mg Hg/m3 of air

c. 100 mg Hg/m3 of air

d. 30 mg Hg/m3 of air

26 / 60

Commonly used filler in composite is 😕

a. Colloidal silica

b. Quartz

c. Aluminum

d. Glass

27 / 60

Binder in the phosphate investment is 😕

a. Phosphoric acid

b. Cristobalite

c. Magnesium oxide and monoammonium phosphate

d. Manganese dioxide

28 / 60

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

a. Amalgam

b. Composite resin

c. Porcelain

d. Gold alloy

29 / 60

A direct restorative material used frequently to restore a portion of a posterior tooth that is subject to large biting forces would possess which of the following properties ?

a. High strength

b. Thermal insulation

c. Esthetics

d. Ease of casting

30 / 60

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

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

b. Faster rate of removal increases the yield strength

c. It is the easiest method of removal

d. It decreases the time for syneresis to occur

31 / 60

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

a. No antibacterial action

b. High alkalinity

c. Low alkalinity

d. No Protein lysing effect

32 / 60

The light from the visible light curing unit can cause 😕

a. Iritis

b. Retinal damage

c. Corneal ulceration

d. Cataract

33 / 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

34 / 60

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

a. Gamma I Phase

b. Gamma II Phase

c. Oxide

d. Sulphide

35 / 60

Of the four types of gold casting alloys, the most commonly used for crowns and bridges is 😕

a. Type III

b. Type II

c. Type I

d. Type IV

36 / 60

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

a. Does not alter setting time

b. Decreases setting time

c. Increases setting time

d. Depends on rate of mixing

37 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 60 seconds

b. Phosphoric acid for 60 seconds

c. Polyacrylic acid for 10 seconds

d. Phosphoric acid for 10 seconds

38 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Camphoroquinone

b. Bis-phenol-A

c. Benzoyl methyl ether

d. Toluidine

39 / 60

For proper wetting, contact angle should be ideally 😕

a. 600

b. 900

c. 00

d. 450

40 / 60

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

a. Temperature of specificity

b. Fusion temperature

c. Heat temperature

d. Vapor temperature

41 / 60

The function of gum dammar in inlay wax is 😕

a. No smoothness of pattern

b. No resistance to carving

c. To improve smoothness of pattern

d. Less strength to wax

42 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. After metal is tempered

b. Under compression

c. Under low temperature

d. Several times in air

43 / 60

In the cavities which are more than 2mm deep a light-cured restoration is 😕

a. Fifth generation bonding agent should be applied

b. Restoration should be build in increments

c. Not indicated

d. Cured for longer period

44 / 60

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

a. Teratogenesis

b. Biocompatibility

c. Carcinogenesis

d. Iatrogenesis

45 / 60

Impression compound is characterized by 😕

a. Crystalline in nature with definite melting point

b. Crystalline in nature with high thermal conductivity

c. Amorphous in nature with high thermal conductivity

d. Amorphous in nature with low thermal conductivity

46 / 60

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

a. Carnauba and candellia

b. Montan and Japan coco

c. Spermitic and bees wax

d. Paraffin and microcrystalline wax

47 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Decreases air voids in the restoration

b. Increases strength and abrasive resistance

c. Increases surface smoothness

d. Conserves the material

48 / 60

Commonly used coloring agent in impression plaster is 😕

a. Metallic oxide

b. Congo red

c. Alizarin red

d. Indigo dye

49 / 60

Amalgam is less prone to corrosion 😕

a. If devoid of the gamma 2 phase

b. If it contains 4-6% of copper

c. If it contains zinc

d. If it contains 25-27% of tin

50 / 60

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

a. Reduce brittleness

b. Reduce firing shrinkage

c. increase strength

d. Reduce porosity

51 / 60

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

a. Barium glass

b. Colloidal silica

c. Quartz

d. Lithium aluminum silicate

52 / 60

Potato starch is contained in which impression material ?

a. Impression plaster

b. Impression compound

c. Agar agar

d. Potassium sulfate

53 / 60

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

a. Pulp inflammation

b. Sagging of restoration

c. Porosity in restoration

d. Secondary caries

54 / 60

The following statements about dental porcelains are true except 😕

a. It is brittle in nature

b. Undergoes discoloration

c. Crystalline nature

d. Undergoes firing shrinkage

55 / 60

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

a. It cannot be polished

b. It has low affinity for resin matrix

c. It cause abrasion and wearing of opposing tooth surface

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

56 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It is relatively soft and ductile

b. It does not oxidize

c. Pure zinc has no application in dentistry

d. It is low in strength

57 / 60

The desirable quality of porcelain is 😕

a. Requirement of color

b. Toughness without brittleness

c. Thermal expansion

d. Translucency

58 / 60

Which of the following statements about laboratory composites are true ?

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

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

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

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

59 / 60

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

a. Ag-Sn

b. Cu-Sn

c. Sn-Hg

d. Ag-Hg

60 / 60

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

a. Higher strength, low creep, low corrosion

b. Higher strength, high creep, high corrosion

c. Low strength, low creep, low corrosion

d. Higher strength, high creep, low corrosion

Your score is

The average score is 62%

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