Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 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

2 / 60

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

a. Composites

b. Pure gold

c. Silicates

d. Amalgam

3 / 60

Light source in the curing unit is usually 😕

a. Tungsten halogen light bulb

b. Ultraviolet light bulb

c. Infra red bulb

d. Sun light

4 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Can not be used as light cure material

b. Hydropholic in nature

c. Low stiffness

d. High stiffiness

5 / 60

Working time of denture resin should be at least 😕

a. 5 minutes

b. 15 minutes

c. 20 minutes

d. 10 minutes

6 / 60

Greening effect of porcelain is due to 😕

a. Silver

b. Golde

c. Platinum

d. Palladium

7 / 60

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

a. Higher strength

b. High corrosion

c. Low corrosion

d. Higher creep

8 / 60

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

a. Silica

b. Gypsum

c. Quartz

d. Water

9 / 60

A glaze is placed over the finished composite restoration to 😕

a. To change the shade

b. To reduce surface porosities

c. No provide a better peripheral seal

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

10 / 60

The main resin constituent of polishable composite resin is 😕

a. Polycaronate

b. Polymethyl methacrylate

c. Cyanoacrylate

d. Urethane dimethacrylate

11 / 60

Which of the following statements about compomers are true ?

a. They also are know as GIC

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

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.

12 / 60

Commonly used viscosity controller in composites is 😕

a. Methyl methacrylate

b. Bis-GAM

c. TEG-DMA

d. Polyurethanes

13 / 60

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

a. increase strength

b. Reduce brittleness

c. Reduce firing shrinkage

d. Reduce porosity

14 / 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

15 / 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. Compomer

c. Glass ionomer

d. Composite

16 / 60

Which of the following statements about laboratory composites are true ?

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

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

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

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

17 / 60

Hand instruments for composites are made of 😕

a. Stainless steel

b. Titanium

c. Teflon-coated metal

d. Carbon steel

18 / 60

Resistance of a liquid to motion is called 😕

a. Springiness

b. Diffusion

c. Creep

d. Viscosity

19 / 60

In dental porcelains metallic oxides provide 😕

a. Color and provides refractile property

b. Color and increases the strength

c. Color but decreases the strength

d. Provides refractile property and increases strength

20 / 60

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

a. Not indicated

b. Fifth generation bonding agent should be applied

c. Restoration should be build in increments

d. Cured for longer period

21 / 60

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

a. They are attached to lower natural teeth with cements,

b. They are attached to upper natural teeth with cements,

c. Artificial acrylic teeth are attached

d. They are attached to natural teeth with cements,

22 / 60

Oil of clove is sometimes used in preference to eugenal in ZOE paste because :

a. Reduces burning sensation of paste

b. It increases mixing property of paste and therefore improves impression recorded

c. Has a better reaction with zinc oxide

d. To increase setting time

23 / 60

KHN of enamel is 😕

a. 100

b. 90-100

c. 600

d. 300

24 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, mercury, copper and mercury

b. Silver, tin, palladium and zinc

c. Silver, tin, copper and zinc

d. Silver, mercury, copper and zinc

25 / 60

Most commonly used pit and fissure sealant is 😕

a. Unfilled acrylic

b. Bis-GMA resin

c. Polyurethane

d. Filled acrylic

26 / 60

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

a. Provide thermal insulation

b. Provide strength of amalgam

c. Provide electrical insulation

d. Reduce early marginal leakage tooth structure

27 / 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. 30 ng Hg/m3 of air

c. 100 ng Hg/m3 of air

d. 0.05 mg Hg/m3 of air

28 / 60

Which of these statements are correct in terms of preparing a correctly triturated mass of amalgam ?

a. An overmixed mass is removed readily from the capsule but is soupy in appearance.

b. Dental amalgam is a mixture of silver alloys and mercury.

c. An undertriturated mass is crumbly and dull.

d. A correctly triturated mass is a smooth homogeneous, and dull.

29 / 60

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

a. Decreases setting time

b. Depends on rate of mixing

c. Increases setting time

d. Does not alter setting time

30 / 60

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

a. Heat temperature

b. Fusion temperature

c. Vapor temperature

d. Temperature of specificity

31 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It is low in strength

b. It does not oxidize

c. Pure zinc has no application in dentistry

d. It is relatively soft and ductile

32 / 60

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

a. No antibacterial action

b. No Protein lysing effect

c. Low alkalinity

d. High alkalinity

33 / 60

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

a. Tensile stress

b. Shear stress

c. Impact stress

d. Compressive stress

34 / 60

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

a. Is used as a permanent restorative material in adults

b. The least irritant to the pulp

c. Has an obtudant effect on the pulp

d. Is the oldest luting agent

35 / 60

Minimum light exposure time for composite resins should be 😕

a. 20 sec

b. 5 sec

c. 40 sec

d. 10 sec

36 / 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

37 / 60

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

a. 3:1

b. 2:1

c. 1:3

d. 1:2

38 / 60

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

a. Cu-Sn

b. Ag-Hg

c. Ag-Su

d. Sn-Hg

39 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can be cleaned properly

b. It can not lead to fungal growth

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

d. It can not lead to cleaned property

40 / 60

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

a. Acrylic resin

b. Composite resin

c. Amalgam

d. Glass ionomer

41 / 60

Nickel in base metal alloys increase its 😕

a. Modulus of elasticity

b. Strength

c. S Ductility

d. Hardness and fusion temperature

42 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Bonding with tooth structure

b. Bonding between coupling agent and filler

c. Bonding between coupling agent and tooth structure

d. Adhesive bonding between matrix and filler

43 / 60

Stearic acid in impression compound 😕

a. Reduces brittleness

b. Reduces plasticity

c. Reduces flow

d. Increase setting time

44 / 60

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

a. Biocompatibility

b. Flow

c. Adhesion

d. Dimensional stability

45 / 60

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

a. Micrographs of alloys particles.

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

c. Wear facets along the occlusal contach areas

d. Marginal ditching along occlusal margins

46 / 60

Color stability of cold-cured resins is inferior to that of heat cured resins due to 😕

a. Decreased polymerization of the resin

b. Variation in the molecular weight of the resin (low mol wt)

c. Increased solubility of the resin

d. Subsequent oxidation of the tertiary amine

47 / 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

48 / 60

When a mechanical device is used for mixing addition silicones 😕

a. Mixing time is long

b. More possibilities of contamination

c. There is no greater uniformity in proportioning and mixing

d. Mixing time is reduced

49 / 60

Potato starch is contained in which impression material ?

a. Potassium sulfate

b. Impression plaster

c. Impression compound

d. Agar agar

50 / 60

The byproduct in condensation silicones is 😕

a. Butyl alcohol

b. Propyl alcohol

c. Methyl alcohol

d. Ethyl alcohol

51 / 60

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

a. All of them are polymers

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

c. All of them are a result of secondary reaction

d. All of them should be heated before using

52 / 60

Crystal structures of metals are all the following except 😕

a. Tetragonal

b. Circular

c. Cubic

d. Monoclinic

53 / 60

One of the following statements which one is incorrect regarding polyether :

a. The base paste consists of polyether polymer

b. Aromatic sulfonate ester acts as a cross linking agent

c. The main chain consists of copolymer of methylene oxide and tetrahydrofuran

d. The main chain of polyether consists of copolymer of ethylene oxide and tetrahydrofuran

54 / 60

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

a. Ag-Su

b. Sn-Hg

c. Ag-Hg

d. Cu-Sn

55 / 60

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

a. Condensation silicones

b. Polyether

c. Polysulfides

d. Addition silicones

56 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Polishing

b. Deflasking

c. Packing

d. Curing

57 / 60

If the light cure resin is curd in increments, it helps in 😕

a. Compensating polymerization shrinkage

b. Providing strength to the restoration

c. Saving the application of bonding agent

d. Achieving complete polymerization

58 / 60

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

a. Composite restorative resins

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

c. Has the toxic properties of unreacted mercury

d. Is combined primarily with silver

59 / 60

The main use of zinc oxide eugenol cement is 😕

a. Permanent restoration

b. Base

c. Temporary restoration

d. Indirect pulp capping agent

60 / 60

Distortion on removal from undercuts in addition silicones is very less due to 😕

a. Shrinkage of material

b. Stiffness of the material

c. Lowest strain in compression

d. Increased strain rate on unset material

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The average score is 42%

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