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 is relatively soft and ductile

c. It does not oxidize

d. It is low in strength

2 / 60

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

a. 100 ng Hg/m3 of air

b. 30 ng Hg/m3 of air

c. 0.05 mg Hg/m3 of air

d. All are corrects

3 / 60

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

a. Resilience

b. Ductility

c. Creep

d. Fatigue

4 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Corrosion increases

b. Compressive strength decreases

c. Tensile strength increases

d. Corrosion decreases

5 / 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

6 / 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 high-copper

c. Tensile strength spherical high-copper

d. Creep irregular low-copper

7 / 60

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

a. Aromatic sulfonate ester acts as a cross linking agent

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

c. The base paste consists of polyether polymer

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

8 / 60

The main function of zinc in amalgam is 😕

a. To increase the shelf-life of an amalgam

b. To prevent the creep

c. To produce delayed expansion

d. To increase the longevity of amalgam after setting

9 / 60

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

a. Brinell hardness test

b. Rockwell hardness test

c. Vichers hardness test

d. Knoop hardness test

10 / 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)

11 / 60

The most commonly used implant type presently is 😕

a. Intramucosal implant

b. Transosteal implant

c. Endosseous

d. Subperiosteal

12 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Zinc oxide eugenol impression paste

b. Polyvinyl siloxane

c. Polyether

d. Alginate

13 / 60

A potentially toxic element in base metal alloys is 😕

a. Molybdenum

b. Boron

c. Beryllium

d. Magnesium

14 / 60

The byproduct in condensation silicones is 😕

a. Propyl alcohol

b. Methyl alcohol

c. Butyl alcohol

d. Ethyl alcohol

15 / 60

A direct restorative material used frequently to restore a portion of a posterior tooth that is subject to large biting forces would possess which of the following properties ?

a. Thermal insulation

b. Ease of casting

c. High strength

d. Esthetics

16 / 60

The main use of zinc oxide eugenol cement is 😕

a. Base

b. Temporary restoration

c. Permanent restoration

d. Indirect pulp capping agent

17 / 60

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

a. Sterilize amalgam scrap

b. Avoid touching freshly mixed amalgam

c. Vacuum up a spill immediately

d. Avoid polishing amalgams

18 / 60

If the light cure resin is curd in increments, it helps in 😕

a. Compensating polymerization shrinkage

b. Achieving complete polymerization

c. Providing strength to the restoration

d. Saving the application of bonding agent

19 / 60

Softening of impressing compound is best accomplished by 😕

a. Oil bath

b. Dry heat

c. Open flame

d. Water bath

20 / 60

A glaze is placed over the finished composite restoration to 😕

a. To reduce surface porosities

b. No provide a better peripheral seal

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

d. To change the shade

21 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Polishing

b. Packing

c. Deflasking

d. Curing

22 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Copper

b. Silver

c. Nickel

d. Cobalt

23 / 60

Resistance of a liquid to motion is called 😕

a. Diffusion

b. Viscosity

c. Springiness

d. Creep

24 / 60

Condensation of porcelain is done by all the methods except 😕

a. Ceramming method

b. Brush addition technique

c. Spatulation method

d. Vibration method

25 / 60

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

a. Hydrolyzes the water if contaminated

b. Decreases the setting time

c. Produces contraction

d. Decreases ductility

26 / 60

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

a. Pulp inflammation

b. Secondary caries

c. Porosity in restoration

d. Sagging of restoration

27 / 60

Polyether is different from other elastomers in the following aspects 😕

a. High stiffiness

b. Can not be used as light cure material

c. Hydropholic in nature

d. Low stiffness

28 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. Several times in air

b. After metal is tempered

c. Under compression

d. Under low temperature

29 / 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. Composite resin

d. Amalgam

30 / 60

Which of the following elastomers is suited for multiple cast pouring 😕

a. Polyether

b. Polysulfide

c. Addition silicone

d. Condensation silicone

31 / 60

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

a. Modulus of elasticity

b. Flexibility

c. Toughness

d. Resilience

32 / 60

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

a. Should bond with dental porcelain

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

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

d. Should be brittle

33 / 60

Montan waxes have the following properties except 😕

a. Have low melting points of 42oC

b. Obtained by extraction from lignite

c. Hard, brittle and lustrous

d. Are mineral waxes

34 / 60

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

a. Dimensionally stable even after 1 week

b. Can be used in automixing devices

c. No evolution of any byproduct under all circumstances

d. Undetectable distortion on removal

35 / 60

A small portion of an anterior tooth would most likely be restored with which of the following ?

a. Gold alloy

b. Amalgam

c. Composite resin

d. Porcelain

36 / 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

c. The amount of copper and tin

d. The amount of copper and silver

37 / 60

When the gold content of gold alloys increases 😕

a. The corrosion resistance increases

b. The percentage elongation decrease

c. Ductility decrease

d. The hardness decrease

38 / 60

Greening effect of porcelain is due to 😕

a. Palladium

b. Platinum

c. Silver

d. Golde

39 / 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

40 / 60

Minimum light exposure time for composite resins should be 😕

a. 5 sec

b. 20 sec

c. 40 sec

d. 10 sec

41 / 60

Acrylic resins are used in which of the following ?

a. Denture bases

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

c. Posterior inlays

d. Anterior onlays

42 / 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

43 / 60

Impression compound is characterized by 😕

a. Crystalline in nature with definite melting point

b. Crystalline in nature with high thermal conductivity

c. Amorphous in nature with low thermal conductivity

d. Amorphous in nature with high thermal conductivity

44 / 60

Ideal method firing of porcelain is by using 😕

a. Shorter firing at low temperatures

b. Shorter firing at higher temperatures

c. Longer firing at high temperatures

d. Longer firing at low temperatures

45 / 60

All are properties of waxes except 😕

a. Plastic deformation

b. Solidification shrinkage

c. Flow

d. Creep

46 / 60

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

a. They are attached to natural teeth with cements,

b. Artificial acrylic teeth are attached

c. They are attached to lower natural teeth with cements,

d. They are attached to upper natural teeth with cements,

47 / 60

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

a. Ceramic

b. Glass ionomer

c. Waxe

d. Gold

48 / 60

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

a. fluorite release

b. Amalgam scrap stored in a closed container

c. Floor carpeting

d. Baseboard heating

49 / 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

50 / 60

Full denture bases are usually made from which of the following materials ?

a. Acrylic resin

b. Composite restorative resins

c. Ceramic

d. Gold alloys

51 / 60

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

a. Higher strength

b. Low corrosion

c. Higher creep

d. High corrosion

52 / 60

Hand instruments for composites are made of 😕

a. Teflon-coated metal

b. Carbon steel

c. Titanium

d. Stainless steel

53 / 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. Decreased polymerization of the resin

c. Increased solubility of the resin

d. Subsequent oxidation of the tertiary amine

54 / 60

When a mechanical device is used for mixing addition silicones 😕

a. Mixing time is reduced

b. There is no greater uniformity in proportioning and mixing

c. More possibilities of contamination

d. Mixing time is long

55 / 60

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

a. Colloidal silica

b. Lithium aluminum silicate

c. Quartz

d. Barium glass

56 / 60

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

a. Silver alloys

b. Gold alloy

c. Ceramic

d. Amalgam

57 / 60

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

a. Chemico-mechenical bonding

b. High malleafility of metal

c. Chemical bonding

d. Hight ductility of metal

58 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Zinc phosphate

b. Zinc silicophoshpate

c. Polycardoxylate

d. Calcum hydroxide

59 / 60

Which one of the following is not a criterion for a failed high-copper dental amalgam restorations ?

a. Creep of the restoration out of the cavity preparation in proximal areas

b. Marginal ditching along occlusal margins

c. Micrographs of alloys particles.

d. Wear facets along the occlusal contach areas

60 / 60

Bis-GMA is a reaction product of 😕

a. Bis-phenol-A and urethane dimethacrylate

b. Bis-phenol-A and methyl methacrylate

c. Urethane dimethacrylate and glycidyl

d. Bis-phenol-A and glycidyl methacrylate

Your score is

The average score is 42%

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