Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

a. Metal

b. Composite resin

c. Amalgam

d. Gold alloy

2 / 60

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

a. Compomer

b. Composite

c. Glass ionomer

d. Hybrid ionomer

3 / 60

When the gold content of gold alloys increases 😕

a. The corrosion resistance increases

b. The hardness decrease

c. The percentage elongation decrease

d. Ductility decrease

4 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. Condense the unattacked gamma particles

b. Condense the unattacked gamma II particles

c. Condense the unattacked gamma I particles

d. To reduce gamma II particules

5 / 60

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

a. Subperiosteal

b. Intramucosal frames

c. Transosteal frames

d. Endosseus implants

6 / 60

Bis-GMA is a reaction product of 😕

a. Bis-phenol-A and methyl methacrylate

b. Urethane dimethacrylate and glycidyl

c. Bis-phenol-A and glycidyl methacrylate

d. Bis-phenol-A and urethane dimethacrylate

7 / 60

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

a. 1:3

b. 1:2

c. 3:1

d. 2:1

8 / 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. Increased solubility of the resin

c. Decreased polymerization of the resin

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

9 / 60

Hydrocolloid impression should be removed from the mouth with a sharp jerk because 😕

a. It decreases the time for syneresis to occur

b. It is the easiest method of removal

c. Faster rate of removal increases the yield strength

d. The brush heap structure of a gel responds more favorably to a sudden force

10 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Polishing

b. Deflasking

c. Packing

d. Curing

11 / 60

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

a. No Protein lysing effect

b. No antibacterial action

c. High alkalinity

d. Low alkalinity

12 / 60

Which of the following composites give rough surfaced finish ?

a. Microfilled composites

b. Small particle filled composites

c. Conventional composites

d. Hybrid composites

13 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Polyether

b. Condensation silicones

c. Addition silicones

d. Polysulfides

14 / 60

A full crown on a maxillary anterior tooth may be restored with which of the following restorative materials ?

a. Ceramic

b. Composite resin

c. Gold alloys

d. Amalgam

15 / 60

Binder in the phosphate investment is 😕

a. Phosphoric acid

b. Magnesium oxide and monoammonium phosphate

c. Manganese dioxide

d. Cristobalite

16 / 60

Noble metal alloys are classified according to their 😕

a. Castability

b. Melting temperature

c. Dental function

d. Malleability

17 / 60

Biting force in the molar region ranges from 😕

a. 400-890 N

b. 900-1000 N

c. 1000-1300 N

d. 600-1000 N

18 / 60

The main advantage of composites compared to silicates cement is 😕

a. High modulus of resilience

b. Color matching with the tooth structure is excellent

c. Coefficient of thermal expansion close to tooth structure

d. Practically insoluble in oral fluids

19 / 60

Calcium hydroxide is used for 😕

a. Reduce maginal leakage

b. To prevent recurrent caries

c. Pulp capping

d. Reinforce the restoration

20 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Camphoroquinone

b. Bis-phenol-A

c. Benzoyl methyl ether

d. Toluidine

21 / 60

Which of the following waxes used to align of castings before soldering ?

a. Carding wax

b. Sticky wax

c. Base plate wax

d. Utility wax

22 / 60

Working time of denture resin should be at least 😕

a. 15 minutes

b. 10 minutes

c. 20 minutes

d. 5 minutes

23 / 60

Chemically cured resin shrinks:?

a. On the surface only

b. On the base only

c. Towards the center of bulk of material

d. Away from the light source

24 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Facilitate mechanical bonding

b. Remove smear layer

c. Create tags

d. Provide more strenght

25 / 60

The function of gum dammar in inlay wax is 😕

a. No resistance to carving

b. Less strength to wax

c. No smoothness of pattern

d. To improve smoothness of pattern

26 / 60

Adhesion in composites is due to 😕

a. Presence of smear layer

b. Mechanical interlocking

c. True chemical bonding to tooth structure

d. Cohesion

27 / 60

Porosity in denture base resins can be due to 😕

a. Excess heating of resin above its boiling point

b. Well flasking of wax pattern

c. Adequate mixing of liquid and powder components

d. Applying sufficient pressure during polymerization

28 / 60

Wrought metal 😕

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

b. Cannot be rendered corrosion resistant

c. Cannot be heat treated

d. Can be formed by working on a cast metal

29 / 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

30 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. Far below the oral temperature

b. 100C higher than mouth temperature

c. 37-450C

d. 45-600C

31 / 60

Silver has all the following characteristics except 😕

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

b. Whitens when added to alloys

c. Addition of palladium to silver increases corrosion

d. Silver points serve as a root canal filling material

32 / 60

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

a. Ceramic

b. Glass ionomer

c. Gold

d. Waxe

33 / 60

The greatest amount of dimensional change after setting is exhibited by 😕

a. Polysulfides

b. Polyethers

c. Condensation silicones

d. Addition silicones

34 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Greater bony opposition

b. Lesser bony apposition

c. Prolonged healing time

d. Presence of fibrous tissue

35 / 60

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

a. It has poor tensile strength

b. It has an obtudant effect

c. It does not form reparative dentin

d. It does not have anticariogenic activity

36 / 60

Setting of plaster of Paris is a result of 😕

a. Indirect interaction between hemihydrates

b. Interaction between hemihydrates and water

c. Solubility difference between hemihydrates and dehydrate

d. Loss of water from hemihydrates

37 / 60

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

a. Silica

b. Kaolin

c. Feldspar

d. Potash

38 / 60

The most commonly used implant type presently is 😕

a. Transosteal implant

b. Intramucosal implant

c. Endosseous

d. Subperiosteal

39 / 60

Which of the following initiator-accelerator systems is needed for a light-activated composite?

a. Peroxide-amine

b. Organic acid-metal ion

c. Diketone-amine

d. Organic acid-peroxide

40 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, mercury, copper and mercury

b. Silver, tin, copper and zinc

c. Silver, mercury, copper and zinc

d. Silver, tin, palladium and zinc

41 / 60

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

a. All of them should be heated before using

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

c. All of them are polymers

d. All of them are a result of secondary reaction

42 / 60

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

a. Provide strength of amalgam

b. Reduce early marginal leakage tooth structure

c. Provide electrical insulation

d. Provide thermal insulation

43 / 60

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

a. Triturating precapsulated alloy and mercury

b. Mixing in a mortar and pestle

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

d. A cover over the mixing arms on a triturator

44 / 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

45 / 60

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

a. Porcelain will provide good shade

b. Porcelain will crack on cooling

c. Porcelain will not bond with metal

d. Porcelain will wear off

46 / 60

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

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

b. Expand greatly to provide marginal seal against the tooth

c. Properties of amalgam

d. Have little dimensional change

47 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Reduce porosity

b. Get a smooth surface

c. Increase strength

d. Regulate the setting time

48 / 60

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

a. Amalgam scrap stored in a closed container

b. Floor carpeting

c. fluorite release

d. Baseboard heating

49 / 60

The main function of zinc in amalgam is 😕

a. To increase the shelf-life of an amalgam

b. To produce delayed expansion

c. To increase the longevity of amalgam after setting

d. To prevent the creep

50 / 60

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

a. Have longer setting time

b. Requires higher forces of condensation

c. Requires less amalgamation time

d. Requires more mercury for trituration

51 / 60

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

a. Increased strain rate on unset material

b. Stiffness of the material

c. Lowest strain in compression

d. Shrinkage of material

52 / 60

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

a. The base paste consists of polyether polymer

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

c. Aromatic sulfonate ester acts as a cross linking agent

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

53 / 60

The impression material which is routinely used in auto mixing devicee system is 😕

a. Condensation silicone

b. Polysulfied

c. Polyether

d. Polyvinyl siloxane

54 / 60

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

a. Resilience

b. Flexibility

c. Modulus of elasticity

d. Toughness

55 / 60

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

a. 0.05 mg Hg/m3 of air

b. 100 ng Hg/m3 of air

c. All are corrects

d. 30 ng Hg/m3 of air

56 / 60

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

a. Higher strength, low creep, low corrosion

b. Higher strength, high creep, high corrosion

c. Low strength, low creep, low corrosion

d. Higher strength, high creep, low corrosion

57 / 60

Softening of impressing compound is best accomplished by 😕

a. Dry heat

b. Water bath

c. Oil bath

d. Open flame

58 / 60

Potato starch is contained in which impression material ?

a. Potassium sulfate

b. Agar agar

c. Impression plaster

d. Impression compound

59 / 60

Clinical significance of smear layer :

a. Provides calcium for adhesion of composites

b. Bonded to tooth structure and prevents composite adhesion

c. Increases the bonding action of the bonding agent

d. Improve the strength of the composite

60 / 60

Inorganic phase in a composite matrix 😕

a. Decreases the mechanical strength

b. Increases coefficient of thermal expansion

c. Increases the mechanical strength

d. Increases the polymerization shrinkage

Your score is

The average score is 73%

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