Biomaterial Test

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Biomaterial Test

1 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Decreases air voids in the restoration

b. Conserves the material

c. Increases strength and abrasive resistance

d. Increases surface smoothness

2 / 60

In UV curing system the activator employed is 😕

a. Hydroquinone

b. Dibutyl phthalate

c. Methyl methacrylate

d. Benzoin methyl ether

3 / 60

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

a. Lights with both blue and red wavelengths are equally effective for 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. Light from an argon laser will activate polymerization.

4 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Vulcanizing

b. Fritting

c. Fusing

d. Sintering

5 / 60

Thermal conductivity is proportional to 😕

a. Hardness of metal

b. Area of conduction

c. Type of metal

d. Fusion temperature

6 / 60

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

a. Unfilled

b. Glass ionomer cement

c. Silicate cement

d. Amalgam

7 / 60

Hand instruments for composites are made of 😕

a. Teflon-coated metal

b. Titanium

c. Stainless steel

d. Carbon steel

8 / 60

Which of the following base is contraindicated for composites ?

a. Calcium hydroxide

b. Zinc phosphate

c. Zinc oxide eugenol

d. Glass ionomer cement

9 / 60

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

a. Can be used in automixing devices

b. No evolution of any byproduct under all circumstances

c. Dimensionally stable even after 1 week

d. Undetectable distortion on removal

10 / 60

Cavity varnish should not be applied when the following is used as a filling material 😕

a. Amalgam

b. Direct resin-filling material

c. Zinc phosphate

d. Silicate

11 / 60

Gypsum investments should not be heated above 😕

a. 7000C

b. 17000C

c. 4500C

d. 10000C

12 / 60

Metal has the following properties except 😕

a. Electroplated silver and copper are used in dies

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

c. Metal is any element that ionizes positively in solution

d. Pure metals are not useful in dentistry

13 / 60

When the gold content of gold alloys increases 😕

a. The hardness decrease

b. The corrosion resistance increases

c. Ductility decrease

d. The percentage elongation decrease

14 / 60

Which of the following properties would be of least importance, when selecting an impression material ?

a. Dimensional stability

b. Flow

c. Adhesion

d. Biocompatibility

15 / 60

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

a. Polyether

b. Addition silicones

c. Condensation silicones

d. Polysulfides

16 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Packing

b. Curing

c. Deflasking

d. Polishing

17 / 60

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

a. Artificial waxes teeth are attached

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

c. They are attached to natural teeth with cements,

d. Carbone steal

18 / 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

19 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. Under compression

b. After metal is tempered

c. Under low temperature

d. Several times in air

20 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Surgical paste

b. Wash impression for edentulous patients

c. Dual impression for Partially edentulous patients

d. As interocclusal record material

21 / 60

The most accurate polysulfide impressions are made by using a custom acrylic tray because 😕

a. More pressure can be applied during impression making

b. It can hold more amount of impression material

c. The tray does not distort during impression making

d. Custom tray made of plastic material ensures a uniform thickness of impression material

22 / 60

Condensation of porcelain is done by all the methods except 😕

a. Ceramming method

b. Vibration method

c. Spatulation method

d. Brush addition technique

23 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Benzoyl methyl ether

b. Camphoroquinone

c. Toluidine

d. Bis-phenol-A

24 / 60

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

a. Composite resin

b. Glass ionomer

c. Amalgam

d. Acrylic resin

25 / 60

Adhesion in composites is due to 😕

a. True chemical bonding to tooth structure

b. Mechanical interlocking

c. Cohesion

d. Presence of smear layer

26 / 60

Stearic acid in impression compound 😕

a. Reduces brittleness

b. Reduces plasticity

c. Increase setting time

d. Reduces flow

27 / 60

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

a. Chemical bonding

b. High malleafility of metal

c. Chemico-mechenical bonding

d. Hight ductility of metal

28 / 60

Which 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. Triturating precapsulated alloy and mercury

d. A cover over the mixing arms on a triturator

29 / 60

Minimum light exposure time for composite resins should be 😕

a. 5 sec

b. 10 sec

c. 20 sec

d. 40 sec

30 / 60

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

a. Higher creep

b. Higher strength

c. High corrosion

d. Low corrosion

31 / 60

The catalyst used for condensation silicones is 😕

a. Stannous octoate

b. Platinum

c. Oleic acid

d. Lead dioxide

32 / 60

The byproduct in condensation silicones is 😕

a. Butyl alcohol

b. Ethyl alcohol

c. Methyl alcohol

d. Propyl alcohol

33 / 60

Softening of impressing compound is best accomplished by 😕

a. Water bath

b. Dry heat

c. Open flame

d. Oil bath

34 / 60

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

a. Polysulfides

b. Condensation silicones

c. Polyethers

d. Addition silicones

35 / 60

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

a. Porcelain will crack on cooling

b. Porcelain will provide good shade

c. Porcelain will wear off

d. Porcelain will not bond with metal

36 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Will take up water and expand if kept wet

b. Is an irreversible hydrocolloid impression material

c. May exhibit a fluid exudates on the surface as a result of imbibitions

d. Will be shrink as a result of syneresis

37 / 60

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

a. 30 mg Hg/m3 of air

b. 0.04 mg Hg/m3 of air

c. 0.05 mg Hg/m3 of air

d. 100 mg Hg/m3 of air

38 / 60

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

a. Potash

b. Silica

c. Feldspar

d. Kaolin

39 / 60

Which of the following composites give rough surfaced finish ?

a. Microfilled composites

b. Conventional composites

c. Hybrid composites

d. Small particle filled composites

40 / 60

Glass ionomer cenment is not recommended for 😕

a. Class V restoration

b. Class III restoration

c. Class I restoration

d. Class IV resoration

41 / 60

Potato starch is contained in which impression material ?

a. Impression compound

b. Impression plaster

c. Agar agar

d. Potassium sulfate

42 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Zinc oxide eugenol impression paste

b. Alginate

c. Polyvinyl siloxane

d. Polyether

43 / 60

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

a. Carbide burs at low to medium speed

b. Diamond burs at low to medium speed

c. Carbide burs at high speed

d. Diamond burs at high speed

44 / 60

Calcium hydroxide is used for 😕

a. Pulp capping

b. Reinforce the restoration

c. Reduce maginal leakage

d. To prevent recurrent caries

45 / 60

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

a. Creep irregular high-copper

b. Tensile strength spherical high-copper

c. 1-hour compressive strength spherical high-copper

d. Creep irregular low-copper

46 / 60

Silver in the set amalgam alloy tends to have the following effect 😕

a. Decreases ductility

b. Produces contraction

c. Decreases the setting time

d. Hydrolyzes the water if contaminated

47 / 60

Light source in the curing unit is usually 😕

a. Ultraviolet light bulb

b. Sun light

c. Tungsten halogen light bulb

d. Infra red bulb

48 / 60

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

a. Requires more mercury for trituration

b. Requires higher forces of condensation

c. Requires less amalgamation time

d. Have longer setting time

49 / 60

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

a. It has more working time available

b. It has not more working time available

c. It is more sensitive to oxygen inhibitors

d. It takes more time for curing

50 / 60

Elgiloy arch wire is 😕

a. Cobalt-chromium-nickel alloy

b. Optical fiber arch wire

c. Gold alloy

d. β-titanium arch wire

51 / 60

For proper wetting, contact angle should be ideally 😕

a. 900

b. 00

c. 600

d. 450

52 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

a. Exactly after four minutes after kneading

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

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

d. When the material is glossy

53 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 10 seconds

b. Phosphoric acid for 60 seconds

c. Polyacrylic acid for 60 seconds

d. Phosphoric acid for 10 seconds

54 / 60

Which of the following is called periphery wax ?

a. Utility wax

b. Bite registration wax

c. Beading wax

d. Sticky wax

55 / 60

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

a. Toughness

b. Brittleness

c. Hardness

d. Springiness

56 / 60

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

a. Their hardness is comparable to stainless steel

b. They have excellent tarnish and corrosion resistance

c. They cannot be soldered or welded

d. They can be heat treated

57 / 60

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

a. Endosseus implants

b. Intramucosal frames

c. Subperiosteal

d. Transosteal frames

58 / 60

Crystal structures of metals are all the following except 😕

a. Cubic

b. Tetragonal

c. Monoclinic

d. Circular

59 / 60

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

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

b. Poly (methyl methacrylate)

c. Pheyl methacrylate

d. Polystyrene

60 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Nickel

b. Silver

c. Copper

d. Cobalt

Your score is

The average score is 73%

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