Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 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

2 / 60

One of the disadvantages of using quartz as filler in restorative resin is 😕

a. It has low affinity for resin matrix

b. It cause abrasion and wearing of opposing tooth surface

c. It cannot be reduced to the size of microparticle composite

d. It cannot be polished

3 / 60

Which of the following statements about laboratory composites are true ?

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

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

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

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

4 / 60

Which of the following composites give rough surfaced finish ?

a. Small particle filled composites

b. Conventional composites

c. Hybrid composites

d. Microfilled composites

5 / 60

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

a. Cu-Sn

b. Ag-Hg

c. Sn-Hg

d. Ag-Sn

6 / 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

7 / 60

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

a. Composites

b. Pure gold

c. Amalgam

d. Silicates

8 / 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

9 / 60

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

a. Cu-Sn

b. Ag-Sn

c. Sn-Hg

d. Ag-Hg

10 / 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. Amalgam

d. Gold alloys

11 / 60

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

a. Adhesion

b. Dimensional stability

c. Flow

d. Biocompatibility

12 / 60

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

a. Acrylic resin

b. Gold alloys

c. Composite restorative resins

d. Ceramic

13 / 60

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

a. Reactors

b. Retarders

c. Fillers

d. Accelerators

14 / 60

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

a. Shrinkage of material

b. Stiffness of the material

c. Increased strain rate on unset material

d. Lowest strain in compression

15 / 60

Wet porcelain is condensed properly before firing to enhance all the properties except : ?

a. increase strength

b. Reduce firing shrinkage

c. Reduce porosity

d. Reduce brittleness

16 / 60

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

a. Diamond burs at high speed

b. Diamond burs at low to medium speed

c. Carbide burs at low to medium speed

d. Carbide burs at high speed

17 / 60

Wrought metal 😕

a. Cannot be heat treated

b. Can be formed by working on a cast metal

c. Cannot be rendered corrosion resistant

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

18 / 60

Amalgam is less prone to corrosion 😕

a. If it contains 4-6% of copper

b. If it contains 25-27% of tin

c. If devoid of the gamma 2 phase

d. If it contains zinc

19 / 60

Which of the following is called periphery wax ?

a. Bite registration wax

b. Utility wax

c. Sticky wax

d. Beading wax

20 / 60

Minimal thickness of base for adequate thermal insulation is 😕

a. 2 mm

b. 0.75 mm

c. 0.5 mm

d. 1 mm

21 / 60

In the cavities which are more than 2mm deep a light-cured restoration is 😕

a. Not indicated

b. Restoration should be build in increments

c. Cured for longer period

d. Fifth generation bonding agent should be applied

22 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It is low in strength

b. It does not oxidize

c. It is relatively soft and ductile

d. Pure zinc has no application in dentistry

23 / 60

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

a. Triturating precapsulated alloy and mercury

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

c. Mixing in a mortar and pestle

d. A cover over the mixing arms on a triturator

24 / 60

When a mechanical device is used for mixing addition silicones 😕

a. Mixing time is reduced

b. Mixing time is long

c. There is no greater uniformity in proportioning and mixing

d. More possibilities of contamination

25 / 60

Oil of clove is sometimes used in preference to eugenal in ZOE paste because :

a. Reduces burning sensation of paste

b. Has a better reaction with zinc oxide

c. To increase setting time

d. It increases mixing property of paste and therefore improves impression recorded

26 / 60

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

a. Sticky wax

b. Carding wax

c. Base plate wax

d. Utility wax

27 / 60

The catalyst used for condensation silicones is 😕

a. Lead dioxide

b. Oleic acid

c. Stannous octoate

d. Platinum

28 / 60

Which statements are true for bonding of amalgam to tooth structure ?

a. The most effective bonding agents contain copalite.

b. The use of amalgam bonding reduces marginal leakage of amalgam restorations.

c. The use of amalgam bonding restores the strength of the clinical crown to its original condition.

d. Shear bond strength using amalgam bonding to teeth in clinically proven to be as high as that for bonding composites to teeth.

29 / 60

Which of the following statements is incorrect regarding hydroxyapatite as an implant material ?

a. It is a bio-inert material

b. This material in granular form and is difficult

c. It is used for augmenting alveolar ridges of filling bony defects

d. It is produced in block or granula form

30 / 60

Greening effect of porcelain is due to 😕

a. Palladium

b. Silver

c. Golde

d. Platinum

31 / 60

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

a. Pulp inflammation

b. Secondary caries

c. Sagging of restoration

d. Porosity in restoration

32 / 60

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

a. Carbone steal

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

c. Artificial waxes teeth are attached

d. They are attached to natural teeth with cements,

33 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Cobalt

b. Silver

c. Copper

d. Nickel

34 / 60

KHN of enamel is 😕

a. 300

b. 90-100

c. 100

d. 600

35 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Increases surface smoothness

b. Decreases air voids in the restoration

c. Conserves the material

d. Increases strength and abrasive resistance

36 / 60

Softening of impressing compound is best accomplished by 😕

a. Open flame

b. Water bath

c. Oil bath

d. Dry heat

37 / 60

Calcium hydroxide is used for 😕

a. To prevent recurrent caries

b. Pulp capping

c. Reinforce the restoration

d. Reduce maginal leakage

38 / 60

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

a. All of them are a result of secondary reaction

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

c. All of them are polymers

d. All of them should be heated before using

39 / 60

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

a. They can be heat treated

b. Their hardness is comparable to stainless steel

c. They cannot be soldered or welded

d. They have excellent tarnish and corrosion resistance

40 / 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

41 / 60

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

a. Polyvinyl siloxane

b. Condensation silicone

c. Polyether

d. Polysulfied

42 / 60

Porosity in denture base resins can be due to 😕

a. Excess heating of resin above its boiling point

b. Applying sufficient pressure during polymerization

c. Adequate mixing of liquid and powder components

d. Well flasking of wax pattern

43 / 60

For proper wetting, contact angle should be ideally 😕

a. 00

b. 450

c. 900

d. 600

44 / 60

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

a. Produces contraction

b. Decreases the setting time

c. Hydrolyzes the water if contaminated

d. Decreases ductility

45 / 60

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

a. Brittleness

b. Springiness

c. Hardness

d. Toughness

46 / 60

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

a. Amalgam

b. Direct resin-filling material

c. Silicate

d. Zinc phosphate

47 / 60

Light source in the curing unit is usually 😕

a. Infra red bulb

b. Sun light

c. Ultraviolet light bulb

d. Tungsten halogen light bulb

48 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Difficult to manipulate

b. Bond between agar and alginate is not very strong

c. Cost factor is high

d. Maximum details are not produced

49 / 60

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

a. Requires higher forces of condensation

b. Have longer setting time

c. Requires less amalgamation time

d. Requires more mercury for trituration

50 / 60

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

a. Glass ionomer

b. Acrylic resin

c. Composite resin

d. Amalgam

51 / 60

Which one of the following is not true about high-copper dental amalgam restorations ?

a. Contain both Sn and Ag in the composition as well

b. Produce excessive creep

c. Restorations are more brittle than low-copper versions

d. Better corrosion resistance than low-copper dental amalgams

52 / 60

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

a. Sn-Hg

b. Cu-Sn

c. Ag-Hg

d. Ag-Su

53 / 60

Metal has the following properties except 😕

a. Metal is any element that ionizes positively in solution

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

c. Electroplated silver and copper are used in dies

d. Pure metals are not useful in dentistry

54 / 60

All are properties of waxes except 😕

a. Flow

b. Plastic deformation

c. Solidification shrinkage

d. Creep

55 / 60

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

a. fluorite release

b. Baseboard heating

c. Floor carpeting

d. Amalgam scrap stored in a closed container

56 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. Far below the oral temperature

b. 45-600C

c. 37-450C

d. 100C higher than mouth temperature

57 / 60

Silver has all the following characteristics except 😕

a. Addition of palladium to silver increases corrosion

b. Silver points serve as a root canal filling material

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

d. Whitens when added to alloys

58 / 60

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

a. Polyethers

b. Addition silicones

c. Condensation silicones

d. Polysulfides

59 / 60

Montan waxes have the following properties except 😕

a. Have low melting points of 42oC

b. Hard, brittle and lustrous

c. Obtained by extraction from lignite

d. Are mineral waxes

60 / 60

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

a. Mixing in a mortar and pestle

b. Triturating precapsulated alloy and mercury

c. A cover over the mixing arms on a triturator

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

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