Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

Thickness of the gel between the tray and tissue for either agar or alginate should always be at least 😕

a. 4 mm

b. 3 mm

c. 2 mm

d. 1 mm

2 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Toluidine

b. Bis-phenol-A

c. Camphoroquinone

d. Benzoyl methyl ether

3 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Copper

b. Silver

c. Cobalt

d. Nickel

4 / 60

Gold casting alloys are classified as type I, II, III or IV among these, having highest hardness is 😕

a. Type II

b. Type III

c. Type I

d. Type IV

5 / 60

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

a. Silicate cement

b. Glass ionomer cement

c. Composite resin

d. Unfilled acrylic resin

6 / 60

Which of the following statements about laboratory composites are true ?

a. Fiber reinforcement increases their strength but decrease their rigidity.

b. Bridge prepared from laboratory composites require a metal substructure.

c. Curing using light, heat, and pressure increase the wear resistance.

d. Restorations prepared from laboratory composites typically are cemented with zinc phosphate cement.

7 / 60

Metal has the following properties except 😕

a. Pure metals are not useful in dentistry

b. Metal is any element that ionizes positively in solution

c. Electroplated silver and copper are used in dies

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

8 / 60

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

a. All are corrects

b. 0.05 mg Hg/m3 of air

c. 30 ng Hg/m3 of air

d. 100 ng Hg/m3 of air

9 / 60

When a mechanical device is used for mixing addition silicones 😕

a. More possibilities of contamination

b. Mixing time is reduced

c. Mixing time is long

d. There is no greater uniformity in proportioning and mixing

10 / 60

The main resin constituent of polishable composite resin is 😕

a. Polycaronate

b. Urethane dimethacrylate

c. Polymethyl methacrylate

d. Cyanoacrylate

11 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Alginate

b. Polyvinyl siloxane

c. Zinc oxide eugenol impression paste

d. Polyether

12 / 60

In dental plaster the main ingredient is 😕

a. Calcium sulfate hemihydarate

b. Calcium sulfate dehydrate

c. Calcium anhydrate

d. Calcium phosphate

13 / 60

Dental personnel can do which one of the following to limit their exposure to mercury ?

a. Vacuum up a spill immediately

b. Sterilize amalgam scrap

c. Avoid touching freshly mixed amalgam

d. Avoid polishing amalgams

14 / 60

KHN of enamel is 😕

a. 100

b. 90-100

c. 300

d. 600

15 / 60

The function of gum dammar in inlay wax is 😕

a. Less strength to wax

b. To improve smoothness of pattern

c. No smoothness of pattern

d. No resistance to carving

16 / 60

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

a. 1-hour compressive strength spherical high-copper

b. Creep irregular low-copper

c. Tensile strength spherical high-copper

d. Creep irregular high-copper

17 / 60

Acrylic resins are used in which of the following ?

a. Ceramic ( porcelain )-fused-to-metal crowns

b. Anterior onlays

c. Denture bases

d. Posterior inlays

18 / 60

Regarding Knoop hardness number, which of the following material is closest to that of dentine (KHN 65) ?

a. Silicates

b. Composites

c. Pure gold

d. Amalgam

19 / 60

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

a. Triturating precapsulated alloy and mercury

b. A cover over the mixing arms on a triturator

c. Mixing in a mortar and pestle

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

20 / 60

The desirable quality of porcelain is 😕

a. Requirement of color

b. Toughness without brittleness

c. Thermal expansion

d. Translucency

21 / 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)

22 / 60

Porcelain denture teeth 😕

a. Have higher coefficient of thermal expansion than resin teeth

b. Are easy to grind and polish

c. Have decreased abrasion resistance than dentin

d. Are more resistant of abrasion than gold

23 / 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. Glass ionomer

c. Amalgam

d. Composite resin

24 / 60

Condensation of porcelain is done by all the methods except 😕

a. Brush addition technique

b. Vibration method

c. Spatulation method

d. Ceramming method

25 / 60

Resistance of a liquid to motion is called 😕

a. Viscosity

b. Springiness

c. Creep

d. Diffusion

26 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Reduce porosity

b. Increase strength

c. Get a smooth surface

d. Regulate the setting time

27 / 60

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

a. Lithium aluminum silicate

b. Barium glass

c. Colloidal silica

d. Quartz

28 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. After metal is tempered

b. Under compression

c. Several times in air

d. Under low temperature

29 / 60

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

a. Has an obtudant effect on the pulp

b. Is the oldest luting agent

c. The least irritant to the pulp

d. Is used as a permanent restorative material in adults

30 / 60

Which of the following statements about compomers are true ?

a. Because of their resin content, they require a bonding agent for adhesion to tooth structure.

b. They also are know as GIC

c. They are two-paste systems that self-cure within 2 to 3 minutes.

d. They typically are recommended for class II restorations.

31 / 60

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

a. Condensation silicones

b. Addition silicones

c. Polyether

d. Polysulfides

32 / 60

Which of the following waxes is obtained from distillation of petroleum ?

a. Paraffin and microcrystalline wax

b. Spermitic and bees wax

c. Carnauba and candellia

d. Montan and Japan coco

33 / 60

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

a. Glass ionomer

b. Hybrid ionomer

c. Composite

d. Compomer

34 / 60

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

a. Requires higher forces of condensation

b. Requires more mercury for trituration

c. Requires less amalgamation time

d. Have longer setting time

35 / 60

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

a. The amount of copper and zinc

b. The amount of copper and tin

c. The amount of copper and silver

d. The amount of copper

36 / 60

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

a. Decreases the setting time

b. Produces contraction

c. Hydrolyzes the water if contaminated

d. Decreases ductility

37 / 60

The light from the visible light curing unit can cause 😕

a. Retinal damage

b. Iritis

c. Corneal ulceration

d. Cataract

38 / 60

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

a. Metal

b. Amalgam

c. Composite resin

d. Gold alloy

39 / 60

Crystalline materials have 😕

a. Well-defined melting

b. Less stable space lattice

c. No space lattice

d. No well-defined melting

40 / 60

Main disadvantage of denture base soft reliner is 😕

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

b. It can not lead to fungal growth

c. It can not lead to cleaned property

d. It can be cleaned properly

41 / 60

Working time of denture resin should be at least 😕

a. 10 minutes

b. 5 minutes

c. 15 minutes

d. 20 minutes

42 / 60

Color stability of cold-cured resins is inferior to that of heat cured resins due to 😕

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

b. Subsequent oxidation of the tertiary amine

c. Increased solubility of the resin

d. Decreased polymerization of the resin

43 / 60

Minimal thickness of base for adequate thermal insulation is 😕

a. 0.5 mm

b. 0.75 mm

c. 2 mm

d. 1 mm

44 / 60

The strain at which the plastic strain develops may be represented by 😕

a. Yield strength, tensile strength, toughness

b. Toughness, rigidity, resilience

c. Elastic limit, yield strength, proportional limit

d. Elastic limit, modulus of elasticity, tensile strength

45 / 60

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

a. Higher strength

b. High corrosion

c. Low corrosion

d. Higher creep

46 / 60

Ideal method firing of porcelain is by using 😕

a. Shorter firing at higher temperatures

b. Longer firing at high temperatures

c. Shorter firing at low temperatures

d. Longer firing at low temperatures

47 / 60

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

a. Sn-Hg

b. Cu-Sn

c. Ag-Sn

d. Ag-Hg

48 / 60

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

a. Should bond with dental porcelain

b. Should be brittle

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

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

49 / 60

Montan waxes have the following properties except 😕

a. Are mineral waxes

b. Have low melting points of 42oC

c. Obtained by extraction from lignite

d. Hard, brittle and lustrous

50 / 60

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

a. Porosity in restoration

b. Pulp inflammation

c. Sagging of restoration

d. Secondary caries

51 / 60

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

a. Undetectable distortion on removal

b. Dimensionally stable even after 1 week

c. Can be used in automixing devices

d. No evolution of any byproduct under all circumstances

52 / 60

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

a. Ag-Hg

b. Sn-Hg

c. Cu-Sn

d. Ag-Su

53 / 60

Which of the following materials are used for dental implants ?

a. Cobalt and chromium alloys

b. Gold alloys

c. Metal alloys

d. Titanium

54 / 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. A cover over the mixing arms on a triturator

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

55 / 60

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

a. Fusion temperature

b. Temperature of specificity

c. Heat temperature

d. Vapor temperature

56 / 60

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

a. Carding wax

b. Utility wax

c. Base plate wax

d. Sticky wax

57 / 60

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

a. Polysulfied

b. Polyvinyl siloxane

c. Polyether

d. Condensation silicone

58 / 60

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

a. Platinum-aluminum-vanadium alloy

b. Titanium-aluminum-vanadium alloy

c. Titanium-molybdenum-vanadium alloy

d. Titanium-platinum-aluminum alloy

59 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Vulcanizing

b. Sintering

c. Fusing

d. Fritting

60 / 60

Oxalates, carbonates, potassium, trisodium phosphates are added to alginate as 😕

a. Fillers

b. Reactors

c. Accelerators

d. Retarders

Your score is

The average score is 42%

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