Biomaterial Test

5 votes, 5 avg

164

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Biomaterial Test

1 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Adhesive bonding between matrix and filler

b. Bonding between coupling agent and tooth structure

c. Bonding with tooth structure

d. Bonding between coupling agent and filler

2 / 60

The byproduct in condensation silicones is 😕

a. Ethyl alcohol

b. Butyl alcohol

c. Propyl alcohol

d. Methyl alcohol

3 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Conserves the material

b. Increases strength and abrasive resistance

c. Decreases air voids in the restoration

d. Increases surface smoothness

4 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Bond between agar and alginate is not very strong

b. Maximum details are not produced

c. Cost factor is high

d. Difficult to manipulate

5 / 60

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

a. Acrylic resin

b. Amalgam

c. Glass ionomer

d. Composite resin

6 / 60

The tendency of stainless steel to break under repeated condition of cyclic stressing below the ultimate strength is 😕

a. Ductility

b. Resilience

c. Creep

d. Fatigue

7 / 60

Crystal structures of metals are all the following except 😕

a. Cubic

b. Monoclinic

c. Tetragonal

d. Circular

8 / 60

Which of these statements apply to the filler particles of composites ?

a. Microhybrid composites contain as much as 84% filler by weight.

b. Microfilled

c. All are correct

d. Microfilled composites contain more filler than all-purpose composites.

9 / 60

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

a. Cu-Sn

b. Sn-Hg

c. Ag-Su

d. Ag-Hg

10 / 60

Working time of denture resin should be at least 😕

a. 10 minutes

b. 20 minutes

c. 5 minutes

d. 15 minutes

11 / 60

A potentially toxic element in base metal alloys is 😕

a. Molybdenum

b. Boron

c. Beryllium

d. Magnesium

12 / 60

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

a. Transosteal frames

b. Subperiosteal

c. Intramucosal frames

d. Endosseus implants

13 / 60

Which of the following base is contraindicated for composites ?

a. Glass ionomer cement

b. Zinc oxide eugenol

c. Zinc phosphate

d. Calcium hydroxide

14 / 60

Most commonly used pit and fissure sealant is 😕

a. Unfilled acrylic

b. Filled acrylic

c. Bis-GMA resin

d. Polyurethane

15 / 60

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

a. Utility wax

b. Sticky wax

c. Base plate wax

d. Carding wax

16 / 60

Elgiloy arch wire is 😕

a. Optical fiber arch wire

b. β-titanium arch wire

c. Gold alloy

d. Cobalt-chromium-nickel alloy

17 / 60

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

a. Toughness

b. Impact strength

c. Resilience

d. Flexibility

18 / 60

Silver has all the following characteristics except 😕

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

b. Silver points serve as a root canal filling material

c. Whitens when added to alloys

d. Addition of palladium to silver increases corrosion

19 / 60

The following statements about dental porcelains are true except 😕

a. Undergoes discoloration

b. Crystalline nature

c. Undergoes firing shrinkage

d. It is brittle in nature

20 / 60

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

a. Waxe

b. Ceramic

c. Glass ionomer

d. Gold

21 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Fritting

b. Vulcanizing

c. Sintering

d. Fusing

22 / 60

The restorative material used to restore a small portion of an anterior tooth should have which of the following properties ?

a. Ease of casting

b. High strength

c. Amalgam

d. Esthetics

23 / 60

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

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

b. Mixing in a mortar and pestle

c. A cover over the mixing arms on a triturator

d. Triturating precapsulated alloy and mercury

24 / 60

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

a. Kaolin

b. Feldspar

c. Silica

d. Potash

25 / 60

Which of the following composites give rough surfaced finish ?

a. Hybrid composites

b. Conventional composites

c. Microfilled composites

d. Small particle filled composites

26 / 60

Softening of impressing compound is best accomplished by 😕

a. Water bath

b. Open flame

c. Oil bath

d. Dry heat

27 / 60

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

a. Glass ionomer cement

b. Unfilled acrylic resin

c. Silicate cement

d. Composite resin

28 / 60

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

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

b. The base paste consists of polyether polymer

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

d. Aromatic sulfonate ester acts as a cross linking agent

29 / 60

Metal has the following properties except 😕

a. Electroplated silver and copper are used in dies

b. Metal is any element that ionizes positively in solution

c. Pure metals are not useful in dentistry

d. All metals do not have same degrees of strength and plasticity

30 / 60

Ideal method firing of porcelain is by using 😕

a. Shorter firing at higher temperatures

b. Longer firing at high temperatures

c. Longer firing at low temperatures

d. Shorter firing at low temperatures

31 / 60

Which of the following is called periphery wax ?

a. Bite registration wax

b. Sticky wax

c. Utility wax

d. Beading wax

32 / 60

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

a. The amount of copper and tin

b. The amount of copper and silver

c. The amount of copper and zinc

d. The amount of copper

33 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Corrosion decreases

b. Tensile strength increases

c. Corrosion increases

d. Compressive strength decreases

34 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 45-600C

b. 37-450C

c. 100C higher than mouth temperature

d. Far below the oral temperature

35 / 60

Porcelain denture teeth 😕

a. Have decreased abrasion resistance than dentin

b. Have higher coefficient of thermal expansion than resin teeth

c. Are easy to grind and polish

d. Are more resistant of abrasion than gold

36 / 60

Which of these statements are correct in terms of preparing a correctly triturated mass of amalgam ?

a. An overmixed mass is removed readily from the capsule but is soupy in appearance.

b. A correctly triturated mass is a smooth homogeneous, and dull.

c. An undertriturated mass is crumbly and dull.

d. Dental amalgam is a mixture of silver alloys and mercury.

37 / 60

The catalyst used for condensation silicones is 😕

a. Lead dioxide

b. Platinum

c. Stannous octoate

d. Oleic acid

38 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Lesser bony apposition

b. Presence of fibrous tissue

c. Prolonged healing time

d. Greater bony opposition

39 / 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

40 / 60

Wrought metal 😕

a. Can be formed by working on a cast metal

b. Cannot be rendered corrosion resistant

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

d. Cannot be heat treated

41 / 60

Light source in the curing unit is usually 😕

a. Sun light

b. Tungsten halogen light bulb

c. Ultraviolet light bulb

d. Infra red bulb

42 / 60

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

a. Toughness

b. Springiness

c. Brittleness

d. Hardness

43 / 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.

44 / 60

All of the following are properties of Co-Cr-Ni wires except 😕

a. They can be heat treated

b. They cannot be soldered or welded

c. Their hardness is comparable to stainless steel

d. They have excellent tarnish and corrosion resistance

45 / 60

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

a. Higher strength, high creep, high corrosion

b. Higher strength, low creep, low corrosion

c. Low strength, low creep, low corrosion

d. Higher strength, high creep, low corrosion

46 / 60

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

a. 2:1

b. 3:1

c. 1:3

d. 1:2

47 / 60

In dental porcelains metallic oxides provide 😕

a. Provides refractile property and increases strength

b. Color and provides refractile property

c. Color and increases the strength

d. Color but decreases the strength

48 / 60

Commonly used coloring agent in impression plaster is 😕

a. Indigo dye

b. Congo red

c. Metallic oxide

d. Alizarin red

49 / 60

Minimum light exposure time for composite resins should be 😕

a. 40 sec

b. 10 sec

c. 5 sec

d. 20 sec

50 / 60

Alginate impression material deteriorates rapidly at 😕

a. Elevated temperature

b. Low temperature

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

d. Normal room temperature

51 / 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

52 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Addition silicones

b. Polysulfides

c. Polyether

d. Condensation silicones

53 / 60

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

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

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

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

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

54 / 60

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

a. Should be brittle

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

c. Should bond with dental porcelain

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

55 / 60

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

a. It has not more working time available

b. It has more working time available

c. It takes more time for curing

d. It is more sensitive to oxygen inhibitors

56 / 60

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

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

b. It is the easiest method of removal

c. Faster rate of removal increases the yield strength

d. It decreases the time for syneresis to occur

57 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Increase strength

b. Regulate the setting time

c. Reduce porosity

d. Get a smooth surface

58 / 60

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

a. Ag-Hg

b. Cu-Sn

c. Ag-Sn

d. Sn-Hg

59 / 60

Potato starch is contained in which impression material ?

a. Potassium sulfate

b. Agar agar

c. Impression compound

d. Impression plaster

60 / 60

Which of the following materials are used for dental implants ?

a. Metal alloys

b. Gold alloys

c. Cobalt and chromium alloys

d. Titanium

Your score is

The average score is 86%

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