Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

A measure of ductility of a material is referred to as 😕

a. Proportional limit

b. Percentage elongation

c. Flexibility

d. Yield strength

2 / 60

Proportional limit is defined as :

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

b. A deformation resulting from an applied load

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

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

3 / 60

Which of the following base is contraindicated for composites ?

a. Calcium hydroxide

b. Glass ionomer cement

c. Zinc oxide eugenol

d. Zinc phosphate

4 / 60

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

a. Reduce firing shrinkage

b. Reduce brittleness

c. increase strength

d. Reduce porosity

5 / 60

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

a. High malleafility of metal

b. Chemical bonding

c. Chemico-mechenical bonding

d. Hight ductility of metal

6 / 60

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

a. Ag-Su

b. Cu-Sn

c. Ag-Hg

d. Sn-Hg

7 / 60

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

a. Quartz

b. Silica

c. Water

d. Gypsum

8 / 60

Ideal method firing of porcelain is by using 😕

a. Shorter firing at low temperatures

b. Shorter firing at higher temperatures

c. Longer firing at low temperatures

d. Longer firing at high temperatures

9 / 60

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

a. Porcelain

b. Amalgam

c. Gold alloy

d. Composite resin

10 / 60

Wrought metal 😕

a. Can be formed by working on a cast metal

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

c. Cannot be rendered corrosion resistant

d. Cannot be heat treated

11 / 60

In a porcelain fused to metal restoration, when the coefficient of thermal expansion of metal and porcelain are different 😕

a. Porcelain will wear off

b. Porcelain will not bond with metal

c. Porcelain will crack on cooling

d. Porcelain will provide good shade

12 / 60

Which of the following polymer systems are used for the organic matrix in composites ?

a. Poly (methyl methacrylate)

b. Pheyl methacrylate

c. Bisphenol A-glycidyl methacrylate (Bis-GMA)

d. Polystyrene

13 / 60

Setting time of alginate can be better controlled by 😕

a. Temperature of water used of mixing

b. Chemical accelerators and retarders

c. Mixing time

d. Changing water: powder ratio

14 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Remove smear layer

b. Create tags

c. Facilitate mechanical bonding

d. Provide more strenght

15 / 60

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

a. 2:1

b. 1:2

c. 3:1

d. 1:3

16 / 60

In alginate impression the final gel is 😕

a. Calcium sulphate

b. Sodium alginate

c. Calcium alginate

d. Sodium sulphate

17 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 45-600C

b. 100C higher than mouth temperature

c. Far below the oral temperature

d. 37-450C

18 / 60

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

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

b. Should be brittle

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

d. Should bond with dental porcelain

19 / 60

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

a. Higher strength, high creep, high corrosion

b. Low strength, low creep, low corrosion

c. Higher strength, high creep, low corrosion

d. Higher strength, low creep, low corrosion

20 / 60

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

a. Provide electrical insulation

b. Provide strength of amalgam

c. Provide thermal insulation

d. Reduce early marginal leakage tooth structure

21 / 60

Clinical significance of smear layer :

a. Provides calcium for adhesion of composites

b. Bonded to tooth structure and prevents composite adhesion

c. Improve the strength of the composite

d. Increases the bonding action of the bonding agent

22 / 60

Acrylic resins are used in which of the following ?

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

b. Denture bases

c. Posterior inlays

d. Anterior onlays

23 / 60

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

a. Higher strength

b. Low corrosion

c. High corrosion

d. Higher creep

24 / 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. 4 mm

d. 2 mm

25 / 60

KHN of enamel is 😕

a. 90-100

b. 600

c. 300

d. 100

26 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

a. When the material is glossy

b. When it can be easily indented by a blunt instrument

c. Exactly after four minutes after kneading

d. When the material cannot be intended by a blunt instrument

27 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Ferric oxide

b. Chromium carbide

c. Cobalt oxide

d. Chromium oxide

28 / 60

The following statements about dental porcelains are true except 😕

a. Crystalline nature

b. It is brittle in nature

c. Undergoes firing shrinkage

d. Undergoes discoloration

29 / 60

Compared to lathe-cut alloy, spherical dental amalgam alloys 😕

a. Requires more mercury for trituration

b. Requires less amalgamation time

c. Have longer setting time

d. Requires higher forces of condensation

30 / 60

The desirable quality of porcelain is 😕

a. Thermal expansion

b. Toughness without brittleness

c. Translucency

d. Requirement of color

31 / 60

The main use of zinc oxide eugenol cement is 😕

a. Indirect pulp capping agent

b. Temporary restoration

c. Base

d. Permanent restoration

32 / 60

Greening effect of porcelain is due to 😕

a. Silver

b. Platinum

c. Golde

d. Palladium

33 / 60

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

a. Subsequent oxidation of the tertiary amine

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

c. Decreased polymerization of the resin

d. Increased solubility of the resin

34 / 60

The cracks formed on the ceramic during cooling because 😕

a. Due to external forces

b. The inner layer cools more rapidly than the outer layer

c. The outer layer cools more rapidly than the interior

d. The cooling of the outer and the inner layer occurs at the same rate

35 / 60

Nickel in base metal alloys increase its 😕

a. Strength

b. S Ductility

c. Hardness and fusion temperature

d. Modulus of elasticity

36 / 60

The most commonly employed alloy combination for use in implants is 😕

a. Titanium-molybdenum-vanadium alloy

b. Platinum-aluminum-vanadium alloy

c. Titanium-platinum-aluminum alloy

d. Titanium-aluminum-vanadium alloy

37 / 60

Crystalline materials have 😕

a. Less stable space lattice

b. Well-defined melting

c. No space lattice

d. No well-defined melting

38 / 60

Working time of denture resin should be at least 😕

a. 10 minutes

b. 20 minutes

c. 5 minutes

d. 15 minutes

39 / 60

Most commonly used pit and fissure sealant is 😕

a. Filled acrylic

b. Polyurethane

c. Unfilled acrylic

d. Bis-GMA resin

40 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. Pure zinc has no application in dentistry

b. It is relatively soft and ductile

c. It does not oxidize

d. It is low in strength

41 / 60

Impression compound is characterized by 😕

a. Amorphous in nature with low thermal conductivity

b. Amorphous in nature with high thermal conductivity

c. Crystalline in nature with high thermal conductivity

d. Crystalline in nature with definite melting point

42 / 60

Resistance of a liquid to motion is called 😕

a. Springiness

b. Creep

c. Viscosity

d. Diffusion

43 / 60

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

a. Silicate cement

b. Unfilled

c. Glass ionomer cement

d. Amalgam

44 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To reduce discoloration

b. Reduce surface microporosities

c. To reduce gamma II particule

d. To prevent recurrent carries

45 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, tin, palladium and zinc

b. Silver, mercury, copper and mercury

c. Silver, tin, copper and zinc

d. Silver, mercury, copper and zinc

46 / 60

Which of the following statements about curing of composites are true ?

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

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

c. Lights with both blue and red wavelengths are equally effective for polymerization.

d. Light from an argon laser will activate polymerization.

47 / 60

In UV curing system the activator employed is 😕

a. Dibutyl phthalate

b. Hydroquinone

c. Benzoin methyl ether

d. Methyl methacrylate

48 / 60

Light source in the curing unit is usually 😕

a. Infra red bulb

b. Sun light

c. Ultraviolet light bulb

d. Tungsten halogen light bulb

49 / 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

50 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Bonding between coupling agent and filler

b. Bonding between coupling agent and tooth structure

c. Bonding with tooth structure

d. Adhesive bonding between matrix and filler

51 / 60

The most commonly used implant type presently is 😕

a. Subperiosteal

b. Transosteal implant

c. Endosseous

d. Intramucosal implant

52 / 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. Ease of casting

b. Esthetics

c. High strength

d. Thermal insulation

53 / 60

The catalyst used for condensation silicones is 😕

a. Lead dioxide

b. Oleic acid

c. Platinum

d. Stannous octoate

54 / 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

55 / 60

Alginate impression material deteriorates rapidly at 😕

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

b. Elevated temperature

c. Low temperature

d. Normal room temperature

56 / 60

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

a. Teratogenesis

b. Biocompatibility

c. Carcinogenesis

d. Iatrogenesis

57 / 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. Proportioning mercury and alloy into a friction-fit capsule

d. A cover over the mixing arms on a triturator

58 / 60

Following are the functions of impression compound except 😕

a. To make special tray for final impression

b. To make individual die impression with copper band

c. To make impression of edentulous ridge

d. To record mucostatic impressions

59 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Bond between agar and alginate is not very strong

b. Cost factor is high

c. Difficult to manipulate

d. Maximum details are not produced

60 / 60

Bis-GMA is a reaction product of 😕

a. Bis-phenol-A and methyl methacrylate

b. Bis-phenol-A and urethane dimethacrylate

c. Bis-phenol-A and glycidyl methacrylate

d. Urethane dimethacrylate and glycidyl

Your score is

The average score is 53%

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