Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

Which of the following statements about laboratory composites are true ?

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

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

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

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

2 / 60

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

a. It cannot be polished

b. It cause abrasion and wearing of opposing tooth surface

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

d. It has low affinity for resin matrix

3 / 60

The strain at which the plastic strain develops may be represented by 😕

a. Elastic limit, yield strength, proportional limit

b. Toughness, rigidity, resilience

c. Elastic limit, modulus of elasticity, tensile strength

d. Yield strength, tensile strength, toughness

4 / 60

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

a. Is the oldest luting agent

b. Has an obtudant effect on the pulp

c. The least irritant to the pulp

d. Is used as a permanent restorative material in adults

5 / 60

Crystalline materials have 😕

a. No well-defined melting

b. Well-defined melting

c. Less stable space lattice

d. No space lattice

6 / 60

Calcium hydroxide is used for 😕

a. To prevent recurrent caries

b. Reduce maginal leakage

c. Pulp capping

d. Reinforce the restoration

7 / 60

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

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

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

c. The most effective bonding agents contain copalite.

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

8 / 60

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

a. Specific temperature

b. Latent heat

c. Fusion temperature

d. Temperature of vaporization

9 / 60

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

a. No Protein lysing effect

b. Low alkalinity

c. High alkalinity

d. No antibacterial action

10 / 60

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

a. Composite resin

b. Amalgam

c. Gold alloy

d. Metal

11 / 60

Commonly used coloring agent in impression plaster is 😕

a. Congo red

b. Indigo dye

c. Alizarin red

d. Metallic oxide

12 / 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. Cured for longer period

d. Not indicated

13 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. Several times in air

b. After metal is tempered

c. Under low temperature

d. Under compression

14 / 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.

15 / 60

The reason zinc oxide eugenol cement is used as a temporary restoration 😕

a. It does not form reparative dentin

b. It does not have anticariogenic activity

c. It has poor tensile strength

d. It has an obtudant effect

16 / 60

Chemically cured resin shrinks:?

a. On the base only

b. On the surface only

c. Towards the center of bulk of material

d. Away from the light source

17 / 60

Adhesion in composites is due to 😕

a. True chemical bonding to tooth structure

b. Presence of smear layer

c. Cohesion

d. Mechanical interlocking

18 / 60

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

a. Toughness

b. Brittleness

c. Springiness

d. Hardness

19 / 60

The following statements about dental porcelains are true except 😕

a. Undergoes firing shrinkage

b. Undergoes discoloration

c. It is brittle in nature

d. Crystalline nature

20 / 60

KHN of enamel is 😕

a. 100

b. 90-100

c. 600

d. 300

21 / 60

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

a. Ag-Sn

b. Cu-Sn

c. Ag-Hg

d. Sn-Hg

22 / 60

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

a. Pure gold

b. Amalgam

c. Silicates

d. Composites

23 / 60

Nickel in base metal alloys increase its 😕

a. Strength

b. S Ductility

c. Hardness and fusion temperature

d. Modulus of elasticity

24 / 60

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

a. Amorphous material

b. Space lattice

c. Strain

d. Stress

25 / 60

The fluoride release from glass ionomer cement is 😕

a. 0.005 mg during the first week

b. 0.075 mg during the first month

c. 0.75 mg during the first week

d. 0.0005 mg during the first month

26 / 60

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

a. Amalgam

b. Porcelain

c. Composite resin

d. Gold alloy

27 / 60

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

a. Silicate cement

b. Glass ionomer cement

c. Unfilled

d. Amalgam

28 / 60

The primary difference between low- and high-copper amalgams is which of the following ?

a. The amount of copper and zinc

b. The amount of copper and tin

c. The amount of copper

d. The amount of copper and silver

29 / 60

Light source in the curing unit is usually 😕

a. Ultraviolet light bulb

b. Sun light

c. Tungsten halogen light bulb

d. Infra red bulb

30 / 60

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

a. Produces contraction

b. Decreases the setting time

c. Decreases ductility

d. Hydrolyzes the water if contaminated

31 / 60

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

a. Iatrogenesis

b. Carcinogenesis

c. Teratogenesis

d. Biocompatibility

32 / 60

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

a. Impact strength

b. Toughness

c. Flexibility

d. Resilience

33 / 60

Working time of denture resin should be at least 😕

a. 5 minutes

b. 10 minutes

c. 15 minutes

d. 20 minutes

34 / 60

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

a. Pulp inflammation

b. Porosity in restoration

c. Secondary caries

d. Sagging of restoration

35 / 60

Potato starch is contained in which impression material ?

a. Potassium sulfate

b. Impression plaster

c. Impression compound

d. Agar agar

36 / 60

In UV curing system the activator employed is 😕

a. Hydroquinone

b. Dibutyl phthalate

c. Methyl methacrylate

d. Benzoin methyl ether

37 / 60

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

a. Dimensionally stable even after 1 week

b. No evolution of any byproduct under all circumstances

c. Can be used in automixing devices

d. Undetectable distortion on removal

38 / 60

Inorganic phase in a composite matrix 😕

a. Increases the mechanical strength

b. Increases the polymerization shrinkage

c. Decreases the mechanical strength

d. Increases coefficient of thermal expansion

39 / 60

Which of the following materials are used for dental implants ?

a. Metal alloys

b. Titanium

c. Gold alloys

d. Cobalt and chromium alloys

40 / 60

Setting time of alginate can be better controlled by 😕

a. Changing water: powder ratio

b. Chemical accelerators and retarders

c. Mixing time

d. Temperature of water used of mixing

41 / 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 typically are recommended for class II restorations.

d. They also are know as GIC

42 / 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 can not lead to cleaned property

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

43 / 60

Proportional limit is defined as :

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

b. A deformation resulting from an applied load

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

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

44 / 60

When a mechanical device is used for mixing addition silicones 😕

a. There is no greater uniformity in proportioning and mixing

b. Mixing time is long

c. Mixing time is reduced

d. More possibilities of contamination

45 / 60

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

a. 1:2

b. 2:1

c. 1:3

d. 3:1

46 / 60

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

a. Cu-Sn

b. Ag-Su

c. Sn-Hg

d. Ag-Hg

47 / 60

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

a. Potash

b. Silica

c. Feldspar

d. Kaolin

48 / 60

Acrylic resins are used in which of the following ?

a. Anterior onlays

b. Posterior inlays

c. Ceramic ( porcelain )-fused-to-metal crowns

d. Denture bases

49 / 60

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

a. Composite resin

b. Glass ionomer

c. Amalgam

d. Acrylic resin

50 / 60

Noble metal alloys are classified according to their 😕

a. Castability

b. Melting temperature

c. Malleability

d. Dental function

51 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Compressive strength decreases

b. Tensile strength increases

c. Corrosion increases

d. Corrosion decreases

52 / 60

The noble or base metal alloys used for PFM should have the following requisite :

a. Should be brittle

b. Should bond with dental porcelain

c. Its melting temperature should be low in comparison with firing temperature of porcelain

d. Coefficient of thermal expansion should not be compatible with porcelain

53 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Create tags

b. Remove smear layer

c. Provide more strenght

d. Facilitate mechanical bonding

54 / 60

Montan waxes have the following properties except 😕

a. Are mineral waxes

b. Obtained by extraction from lignite

c. Hard, brittle and lustrous

d. Have low melting points of 42oC

55 / 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

56 / 60

Silver has all the following characteristics except 😕

a. Addition of palladium to silver increases corrosion

b. Whitens when added to alloys

c. Silver points serve as a root canal filling material

d. Silver in pure form is not used in dental restorations

57 / 60

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

a. Gold alloy

b. Ceramic

c. Silver alloys

d. Amalgam

58 / 60

In alginate impression the final gel is 😕

a. Calcium sulphate

b. Calcium alginate

c. Sodium sulphate

d. Sodium alginate

59 / 60

Pick out the incorrect statement regarding alginate impressions 😕

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

b. Is an irreversible hydrocolloid impression material

c. Will be shrink as a result of syneresis

d. Will take up water and expand if kept wet

60 / 60

The most commonly used implant type presently is 😕

a. Subperiosteal

b. Intramucosal implant

c. Transosteal implant

d. Endosseous

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