Biomaterial Test

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Biomaterial Test

1 / 60

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

a. Flow

b. Dimensional stability

c. Biocompatibility

d. Adhesion

2 / 60

Which one of the following is not a criterion for a failed high-copper dental amalgam restorations ?

a. Marginal ditching along occlusal margins

b. Wear facets along the occlusal contach areas

c. Creep of the restoration out of the cavity preparation in proximal areas

d. Micrographs of alloys particles.

3 / 60

Strength of dental porcelain is dependent on 😕

a. Composition

b. Rough

c. No internal structure

d. Resistance to fusion

4 / 60

Noble metal alloys are classified according to their 😕

a. Dental function

b. Castability

c. Melting temperature

d. Malleability

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

c. They are radiolucent.

d. Radiopaque

6 / 60

Light source in the curing unit is usually 😕

a. Sun light

b. Tungsten halogen light bulb

c. Ultraviolet light bulb

d. Infra red bulb

7 / 60

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

a. Polyether

b. Condensation silicone

c. Addition silicone

d. Polysulfide

8 / 60

Nickel in base metal alloys increase its 😕

a. S Ductility

b. Strength

c. Modulus of elasticity

d. Hardness and fusion temperature

9 / 60

Which of the following components acts as a refractory material in porcelain ?

a. Potash

b. Feldspar

c. Silica

d. Kaolin

10 / 60

Binder in the phosphate investment is 😕

a. Magnesium oxide and monoammonium phosphate

b. Manganese dioxide

c. Cristobalite

d. Phosphoric acid

11 / 60

Which of the following is called periphery wax ?

a. Sticky wax

b. Bite registration wax

c. Utility wax

d. Beading wax

12 / 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

13 / 60

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

a. Triturating precapsulated alloy and mercury

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

c. Mixing in a mortar and pestle

d. A cover over the mixing arms on a triturator

14 / 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.

15 / 60

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

a. Amalgam

b. Gold alloy

c. Porcelain

d. Composite resin

16 / 60

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

a. Decreases the setting time

b. Decreases ductility

c. Hydrolyzes the water if contaminated

d. Produces contraction

17 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It does not oxidize

b. It is low in strength

c. Pure zinc has no application in dentistry

d. It is relatively soft and ductile

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

c. Light from an argon laser will activate polymerization.

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

19 / 60

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

a. Reactors

b. Accelerators

c. Retarders

d. Fillers

20 / 60

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

a. Creep

b. Resilience

c. Fatigue

d. Ductility

21 / 60

Impression plaster is a 😕

a. Thermoplastic material

b. Reversible impression material

c. Mucostatic material

d. Mucocompressive material

22 / 60

Softening of impressing compound is best accomplished by 😕

a. Water bath

b. Open flame

c. Oil bath

d. Dry heat

23 / 60

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

a. Addition silicones

b. Polyethers

c. Condensation silicones

d. Polysulfides

24 / 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

c. The amount of copper and silver

d. The amount of copper and zinc

25 / 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. All are corrects

c. 30 ng Hg/m3 of air

d. 100 ng Hg/m3 of air

26 / 60

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

a. Carbone steal

b. Artificial waxes teeth are attached

c. They are attached to natural teeth with cements,

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

27 / 60

Thermal conductivity is proportional to 😕

a. Fusion temperature

b. Hardness of metal

c. Area of conduction

d. Type of metal

28 / 60

Ideally, the set amalgam should do which of the following ?

a. Have little dimensional change

b. Shrink significantly to provide space for correction products to seal the margins

c. Expand greatly to provide marginal seal against the tooth

d. Properties of amalgam

29 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Fritting

b. Vulcanizing

c. Sintering

d. Fusing

30 / 60

Alginate impression material deteriorates rapidly at 😕

a. Low temperature

b. Normal room temperature

c. Elevated temperature

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

31 / 60

The main ingredient of casting waxes is 😕

a. Paraffin wax

b. Carnauba wax

c. Candellila wax

d. Gum dammar

32 / 60

Calcium hydroxide is used for 😕

a. To prevent recurrent caries

b. Pulp capping

c. Reduce maginal leakage

d. Reinforce the restoration

33 / 60

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

a. Space lattice

b. Stress

c. Strain

d. Amorphous material

34 / 60

The fluoride release from glass ionomer cement is 😕

a. 0.005 mg during the first week

b. 0.75 mg during the first week

c. 0.075 mg during the first month

d. 0.0005 mg during the first month

35 / 60

Impression compound is characterized by 😕

a. Crystalline in nature with high thermal conductivity

b. Amorphous in nature with low thermal conductivity

c. Amorphous in nature with high thermal conductivity

d. Crystalline in nature with definite melting point

36 / 60

The most commonly used implant type presently is 😕

a. Intramucosal implant

b. Subperiosteal

c. Transosteal implant

d. Endosseous

37 / 60

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

a. Amalgam

b. Silver alloys

c. Gold alloy

d. Ceramic

38 / 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

39 / 60

Wrought metal 😕

a. Cannot be rendered corrosion resistant

b. Can be formed by pouring molten metal into a mold

c. Can be formed by working on a cast metal

d. Cannot be heat treated

40 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Hydropholic in nature

b. Can not be used as light cure material

c. High stiffiness

d. Low stiffness

41 / 60

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

a. Higher strength

b. High corrosion

c. Higher creep

d. Low corrosion

42 / 60

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

a. Cured for longer period

b. Restoration should be build in increments

c. Fifth generation bonding agent should be applied

d. Not indicated

43 / 60

Condensation of porcelain is done by all the methods except 😕

a. Brush addition technique

b. Spatulation method

c. Ceramming method

d. Vibration method

44 / 60

KHN of enamel is 😕

a. 300

b. 100

c. 600

d. 90-100

45 / 60

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

a. Sn-Hg

b. Ag-Sn

c. Ag-Hg

d. Cu-Sn

46 / 60

Stearic acid in impression compound 😕

a. Increase setting time

b. Reduces flow

c. Reduces brittleness

d. Reduces plasticity

47 / 60

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

a. They cannot be soldered or welded

b. They can be heat treated

c. Their hardness is comparable to stainless steel

d. They have excellent tarnish and corrosion resistance

48 / 60

Resistance of a liquid to motion is called 😕

a. Creep

b. Viscosity

c. Springiness

d. Diffusion

49 / 60

In an alloy oxygen scavenger is 😕

a. Palladium

b. Zinc

c. Copper

d. Silver

50 / 60

Gold casting alloys are classified as type I, II, III or IV among these, having highest hardness is 😕

a. Type IV

b. Type II

c. Type I

d. Type III

51 / 60

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

a. Vapor temperature

b. Temperature of specificity

c. Heat temperature

d. Fusion temperature

52 / 60

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

a. Low strength, low creep, low corrosion

b. Higher strength, low creep, low corrosion

c. Higher strength, high creep, low corrosion

d. Higher strength, high creep, high corrosion

53 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 60 seconds

b. Phosphoric acid for 10 seconds

c. Phosphoric acid for 60 seconds

d. Polyacrylic acid for 10 seconds

54 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Reduce porosity

b. Regulate the setting time

c. Get a smooth surface

d. Increase strength

55 / 60

The constituent that acts as a binder in the investment is 😕

a. Quartz

b. Silica

c. Water

d. Gypsum

56 / 60

Crystalline materials have 😕

a. No well-defined melting

b. Less stable space lattice

c. No space lattice

d. Well-defined melting

57 / 60

Chemically cured resin shrinks:?

a. On the base only

b. Away from the light source

c. Towards the center of bulk of material

d. On the surface only

58 / 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. 30 mg Hg/m3 of air

c. 100 mg Hg/m3 of air

d. 0.04 mg Hg/m3 of air

59 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Cobalt

b. Silver

c. Copper

d. Nickel

60 / 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

Your score is

The average score is 60%

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