Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

a. Lithium aluminum silicate

b. Colloidal silica

c. Barium glass

d. Quartz

2 / 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. They have excellent tarnish and corrosion resistance

d. Their hardness is comparable to stainless steel

3 / 60

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

a. Reduce porosity

b. increase strength

c. Reduce firing shrinkage

d. Reduce brittleness

4 / 60

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

a. Light from an argon laser will activate polymerization.

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

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

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

5 / 60

Most commonly used pit and fissure sealant is 😕

a. Bis-GMA resin

b. Unfilled acrylic

c. Polyurethane

d. Filled acrylic

6 / 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

7 / 60

Which of the following is called periphery wax ?

a. Bite registration wax

b. Beading wax

c. Utility wax

d. Sticky wax

8 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Bonding with tooth structure

b. Bonding between coupling agent and filler

c. Adhesive bonding between matrix and filler

d. Bonding between coupling agent and tooth structure

9 / 60

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

a. Kaolin

b. Potash

c. Feldspar

d. Silica

10 / 60

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

a. Flexibility

b. Toughness

c. Resilience

d. Impact strength

11 / 60

Which of the following represents the maximum safe concentration of mercury vapor in the breathing zone for a 40-hour workweek ?

a. 30 ng Hg/m3 of air

b. 100 ng Hg/m3 of air

c. All are corrects

d. 0.05 mg Hg/m3 of air

12 / 60

Light source in the curing unit is usually 😕

a. Infra red bulb

b. Ultraviolet light bulb

c. Sun light

d. Tungsten halogen light bulb

13 / 60

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

a. No evolution of any byproduct under all circumstances

b. Undetectable distortion on removal

c. Dimensionally stable even after 1 week

d. Can be used in automixing devices

14 / 60

KHN of enamel is 😕

a. 300

b. 100

c. 600

d. 90-100

15 / 60

Setting of plaster of Paris is a result of 😕

a. Loss of water from hemihydrates

b. Interaction between hemihydrates and water

c. Indirect interaction between hemihydrates

d. Solubility difference between hemihydrates and dehydrate

16 / 60

The main use of zinc oxide eugenol cement is 😕

a. Temporary restoration

b. Base

c. Permanent restoration

d. Indirect pulp capping agent

17 / 60

Excess composite from the labial surfaces can be removed by using 😕

a. Diamond burs at high speed

b. Carbide burs at high speed

c. Carbide burs at low to medium speed

d. Diamond burs at low to medium speed

18 / 60

Gypsum investments should not be heated above 😕

a. 10000C

b. 4500C

c. 7000C

d. 17000C

19 / 60

Minimal thickness of base for adequate thermal insulation is 😕

a. 0.75 mm

b. 1 mm

c. 0.5 mm

d. 2 mm

20 / 60

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

a. Sn-Hg

b. Cu-Sn

c. Ag-Hg

d. Ag-Su

21 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To reduce gamma II particule

b. Reduce surface microporosities

c. To prevent recurrent carries

d. To reduce discoloration

22 / 60

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

a. Temperature of specificity

b. Heat temperature

c. Fusion temperature

d. Vapor temperature

23 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Polishing

b. Deflasking

c. Packing

d. Curing

24 / 60

Nickel in base metal alloys increase its 😕

a. S Ductility

b. Hardness and fusion temperature

c. Strength

d. Modulus of elasticity

25 / 60

The main advantage of composites compared to silicates cement is 😕

a. Color matching with the tooth structure is excellent

b. Practically insoluble in oral fluids

c. High modulus of resilience

d. Coefficient of thermal expansion close to tooth structure

26 / 60

Condensation of porcelain is done by all the methods except 😕

a. Brush addition technique

b. Ceramming method

c. Vibration method

d. Spatulation method

27 / 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. Marginal ditching along occlusal margins

d. Wear facets along the occlusal contach areas

28 / 60

Crystalline materials have 😕

a. Less stable space lattice

b. Well-defined melting

c. No space lattice

d. No well-defined melting

29 / 60

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

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

b. Has the toxic properties of unreacted mercury

c. Composite restorative resins

d. Is combined primarily with silver

30 / 60

Stearic acid in impression compound 😕

a. Reduces brittleness

b. Reduces flow

c. Reduces plasticity

d. Increase setting time

31 / 60

In an alloy oxygen scavenger is 😕

a. Copper

b. Zinc

c. Palladium

d. Silver

32 / 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. Glass ionomer

c. Compomer

d. Composite

33 / 60

Clinical significance of smear layer :

a. Provides calcium for adhesion of composites

b. Increases the bonding action of the bonding agent

c. Improve the strength of the composite

d. Bonded to tooth structure and prevents composite adhesion

34 / 60

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

a. Porcelain

b. Gold alloy

c. Amalgam

d. Composite resin

35 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, tin, copper and zinc

b. Silver, mercury, copper and mercury

c. Silver, tin, palladium and zinc

d. Silver, mercury, copper and zinc

36 / 60

The main function of zinc in amalgam is 😕

a. To prevent the creep

b. To increase the shelf-life of an amalgam

c. To increase the longevity of amalgam after setting

d. To produce delayed expansion

37 / 60

Impression plaster is a 😕

a. Thermoplastic material

b. Mucocompressive material

c. Reversible impression material

d. Mucostatic material

38 / 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 bond with dental porcelain

c. Should be brittle

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

39 / 60

The byproduct in condensation silicones is 😕

a. Butyl alcohol

b. Methyl alcohol

c. Propyl alcohol

d. Ethyl alcohol

40 / 60

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

a. 2:1

b. 1:3

c. 3:1

d. 1:2

41 / 60

Which of the following base is contraindicated for composites ?

a. Calcium hydroxide

b. Glass ionomer cement

c. Zinc phosphate

d. Zinc oxide eugenol

42 / 60

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

a. Platinum-aluminum-vanadium alloy

b. Titanium-molybdenum-vanadium alloy

c. Titanium-platinum-aluminum alloy

d. Titanium-aluminum-vanadium alloy

43 / 60

A glaze is placed over the finished composite restoration to 😕

a. To change the shade

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

c. To reduce surface porosities

d. No provide a better peripheral seal

44 / 60

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

a. To increase setting time

b. Reduces burning sensation of paste

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

d. Has a better reaction with zinc oxide

45 / 60

Which of the following composite is recommended for non stress bearing anterior restoration ?

a. Hybrid composites

b. Small particles

c. Microfilled composites

d. Conventional composites

46 / 60

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

a. Glass ionomer cement

b. Silicate cement

c. Amalgam

d. Unfilled

47 / 60

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

a. Sn-Hg

b. Ag-Sn

c. Cu-Sn

d. Ag-Hg

48 / 60

Resistance of a liquid to motion is called 😕

a. Creep

b. Diffusion

c. Springiness

d. Viscosity

49 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can be cleaned properly

b. It can not lead to cleaned property

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

d. It can not lead to fungal growth

50 / 60

When the gold content of gold alloys increases 😕

a. The hardness decrease

b. The percentage elongation decrease

c. Ductility decrease

d. The corrosion resistance increases

51 / 60

Impression compound is characterized by 😕

a. Amorphous in nature with high thermal conductivity

b. Crystalline in nature with high thermal conductivity

c. Crystalline in nature with definite melting point

d. Amorphous in nature with low thermal conductivity

52 / 60

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

a. Expand greatly to provide marginal seal against the tooth

b. Properties of amalgam

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

d. Have little dimensional change

53 / 60

The fluoride release from glass ionomer cement is 😕

a. 0.0005 mg during the first month

b. 0.75 mg during the first week

c. 0.005 mg during the first week

d. 0.075 mg during the first month

54 / 60

Alginate impression material deteriorates rapidly at 😕

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

b. Low temperature

c. Normal room temperature

d. Elevated temperature

55 / 60

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

a. Chemical bonding

b. Hight ductility of metal

c. Chemico-mechenical bonding

d. High malleafility of metal

56 / 60

The light-cured restorative resins have advantages over chemically activated restorative resins as 😕

a. It is more sensitive to oxygen inhibitors

b. It has not more working time available

c. It has more working time available

d. It takes more time for curing

57 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

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

b. Exactly after four minutes after kneading

c. When the material is glossy

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

58 / 60

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

a. They are attached to natural teeth with cements,

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

c. Artificial waxes teeth are attached

d. Carbone steal

59 / 60

Contamination of zinc-containing amalgam by moisture during triturating or condensation :

a. Results in a marked expansion

b. Has no appreciable effect on properties except to the susceptibility to tarnish

c. Results in a sharp decrease in flow

d. Increases the setting time

60 / 60

For each property, list the amalgam type (irregular low-copper, admixed high-copper, and spherical high-copper ) that has the highest value?.

a. Tensile strength spherical high-copper

b. 1-hour compressive strength spherical high-copper

c. Creep irregular high-copper

d. Creep irregular low-copper

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The average score is 42%

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