Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. Pure zinc has no application in dentistry

b. It does not oxidize

c. It is relatively soft and ductile

d. It is low in strength

2 / 60

Which has the highest viscoelastic property and requires more time to recover from deformation ?

a. Polyether

b. Polysulfide

c. Condensation silicone

d. Addition silicone

3 / 60

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

a. A cover over the mixing arms on a triturator

b. Triturating precapsulated alloy and mercury

c. Mixing in a mortar and pestle

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

4 / 60

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

a. Chemical bonding

b. Hight ductility of metal

c. High malleafility of metal

d. Chemico-mechenical bonding

5 / 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 cannot be intended by a blunt instrument

d. When the material is glossy

6 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Wash impression for edentulous patients

b. As interocclusal record material

c. Surgical paste

d. Dual impression for Partially edentulous patients

7 / 60

In alginate impression the final gel is 😕

a. Calcium alginate

b. Sodium alginate

c. Sodium sulphate

d. Calcium sulphate

8 / 60

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

a. To increase setting time

b. Has a better reaction with zinc oxide

c. Reduces burning sensation of paste

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

9 / 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 should be heated before using

c. All of them are a result of secondary reaction

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

10 / 60

Gypsum investments should not be heated above 😕

a. 7000C

b. 4500C

c. 17000C

d. 10000C

11 / 60

Which of the following statements about adhesion of composite restorations to tooth structure are true ?

a. Most bonding agent bond more effectively to a dry tooth surface.

b. Bonding is achieved to enamel by application of an acid etchant followed by application of a bonding agent and then the composites resin.

c. The bonding agent forms a hybrid layer with enamel.

d. The bonding agent forms a micromechanical bond with enamel but a chemical bond with dentin.

12 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Increase strength

b. Regulate the setting time

c. Get a smooth surface

d. Reduce porosity

13 / 60

Which of the following uses a hardened steel ball indenting tool ?

a. Vichers hardness test

b. Rockwell hardness test

c. Brinell hardness test

d. Knoop hardness test

14 / 60

Which of the following statements apply to the packable composites ?

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

b. Their depth of cure allows bulk polymerization, which has been shown to be clinically effective.

c. Radiopaque

d. They are radiolucent.

15 / 60

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

a. Porcelain will not bond with metal

b. Porcelain will provide good shade

c. Porcelain will wear off

d. Porcelain will crack on cooling

16 / 60

Impression plaster is a 😕

a. Mucocompressive material

b. Reversible impression material

c. Mucostatic material

d. Thermoplastic material

17 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Conserves the material

b. Increases surface smoothness

c. Decreases air voids in the restoration

d. Increases strength and abrasive resistance

18 / 60

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

a. Quartz

b. Gypsum

c. Water

d. Silica

19 / 60

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

a. Ag-Sn

b. Ag-Hg

c. Cu-Sn

d. Sn-Hg

20 / 60

Which of the following composites give rough surfaced finish ?

a. Conventional composites

b. Small particle filled composites

c. Hybrid composites

d. Microfilled composites

21 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 10 seconds

b. Phosphoric acid for 60 seconds

c. Phosphoric acid for 10 seconds

d. Polyacrylic acid for 60 seconds

22 / 60

Ideal method firing of porcelain is by using 😕

a. Longer firing at low temperatures

b. Shorter firing at low temperatures

c. Shorter firing at higher temperatures

d. Longer firing at high temperatures

23 / 60

Which of the following is the best choice of restorative material to achieve moderate to high strength, fluorite release, and esthetics ?

a. Composite

b. Compomer

c. Glass ionomer

d. Hybrid ionomer

24 / 60

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

a. Feldspar

b. Kaolin

c. Silica

d. Potash

25 / 60

A potentially toxic element in base metal alloys is 😕

a. Beryllium

b. Magnesium

c. Molybdenum

d. Boron

26 / 60

Which of the following material has a high coefficient of thermal expansion ?

a. Unfilled acrylic resin

b. Glass ionomer cement

c. Silicate cement

d. Composite resin

27 / 60

A glaze is placed over the finished composite restoration to 😕

a. To change the shade

b. No provide a better peripheral seal

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

d. To reduce surface porosities

28 / 60

Amalgam is less prone to corrosion 😕

a. If it contains 25-27% of tin

b. If it contains 4-6% of copper

c. If devoid of the gamma 2 phase

d. If it contains zinc

29 / 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. Creep irregular high-copper

c. Creep irregular low-copper

d. 1-hour compressive strength spherical high-copper

30 / 60

KHN of enamel is 😕

a. 300

b. 90-100

c. 100

d. 600

31 / 60

Silver has all the following characteristics except 😕

a. Whitens when added to alloys

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

c. Silver points serve as a root canal filling material

d. Addition of palladium to silver increases corrosion

32 / 60

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

a. Polysulfides

b. Addition silicones

c. Condensation silicones

d. Polyether

33 / 60

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

a. Unfilled

b. Amalgam

c. Silicate cement

d. Glass ionomer cement

34 / 60

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

a. Provide thermal insulation

b. Provide electrical insulation

c. Reduce early marginal leakage tooth structure

d. Provide strength of amalgam

35 / 60

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

a. The least irritant to the pulp

b. Is the oldest luting agent

c. Is used as a permanent restorative material in adults

d. Has an obtudant effect on the pulp

36 / 60

For luting purpose, the film thickness should be 😕

a. up to 75 μm

b. minimum 50 μm

c. 25 μm or less

d. ideally 100 μm

37 / 60

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

a. Sagging of restoration

b. Pulp inflammation

c. Secondary caries

d. Porosity in restoration

38 / 60

For proper wetting, contact angle should be ideally 😕

a. 450

b. 00

c. 900

d. 600

39 / 60

Stearic acid in impression compound 😕

a. Increase setting time

b. Reduces brittleness

c. Reduces flow

d. Reduces plasticity

40 / 60

The product that is formed on the surface of the amalgam restoration and frequently result in discoloration is 😕

a. Gamma II Phase

b. Sulphide

c. Gamma I Phase

d. Oxide

41 / 60

Minimal thickness of base for adequate thermal insulation is 😕

a. 0.75 mm

b. 2 mm

c. 1 mm

d. 0.5 mm

42 / 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

43 / 60

Light source in the curing unit is usually 😕

a. Ultraviolet light bulb

b. Sun light

c. Infra red bulb

d. Tungsten halogen light bulb

44 / 60

Which of the following is called periphery wax ?

a. Utility wax

b. Beading wax

c. Sticky wax

d. Bite registration wax

45 / 60

The main advantage of composites compared to silicates cement is 😕

a. Coefficient of thermal expansion close to tooth structure

b. Color matching with the tooth structure is excellent

c. Practically insoluble in oral fluids

d. High modulus of resilience

46 / 60

Softening of impressing compound is best accomplished by 😕

a. Open flame

b. Dry heat

c. Oil bath

d. Water bath

47 / 60

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

a. Percentage elongation

b. Flexibility

c. Proportional limit

d. Yield strength

48 / 60

Which one of the following office conditions minimize the health hazard from spilled mercury ?

a. Baseboard heating

b. Floor carpeting

c. Amalgam scrap stored in a closed container

d. fluorite release

49 / 60

Hand instruments for composites are made of 😕

a. Stainless steel

b. Titanium

c. Carbon steel

d. Teflon-coated metal

50 / 60

Which of the following metals currently are used in dental alloys ?

a. Ceramic

b. Waxe

c. Glass ionomer

d. Gold

51 / 60

Strain that occurs when the material is stressed to its proportional limit is called 😕

a. Toughness

b. Flexibility

c. Modulus of elasticity

d. Resilience

52 / 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

53 / 60

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

a. Low strength, low creep, low corrosion

b. Higher strength, high creep, low corrosion

c. Higher strength, high creep, high corrosion

d. Higher strength, low creep, low corrosion

54 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To reduce discoloration

b. To reduce gamma II particule

c. To prevent recurrent carries

d. Reduce surface microporosities

55 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Fritting

b. Sintering

c. Vulcanizing

d. Fusing

56 / 60

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

a. Pheyl methacrylate

b. Poly (methyl methacrylate)

c. Polystyrene

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

57 / 60

Cobalt-chromium alloy is mostly used for the construction of 😕

a. Endosseus implants

b. Intramucosal frames

c. Transosteal frames

d. Subperiosteal

58 / 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

59 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Corrosion increases

b. Corrosion decreases

c. Compressive strength decreases

d. Tensile strength increases

60 / 60

Most commonly used pit and fissure sealant is 😕

a. Filled acrylic

b. Bis-GMA resin

c. Unfilled acrylic

d. Polyurethane

Your score is

The average score is 42%

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