Biomaterial Test

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Biomaterial Test

1 / 60

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

a. Polystyrene

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

c. Poly (methyl methacrylate)

d. Pheyl methacrylate

2 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Nickel

b. Cobalt

c. Copper

d. Silver

3 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Prolonged healing time

b. Lesser bony apposition

c. Presence of fibrous tissue

d. Greater bony opposition

4 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Corrosion increases

b. Compressive strength decreases

c. Corrosion decreases

d. Tensile strength increases

5 / 60

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

a. Porcelain will not bond with metal

b. Porcelain will crack on cooling

c. Porcelain will wear off

d. Porcelain will provide good shade

6 / 60

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

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

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

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

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

7 / 60

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

a. Polysulfide

b. Addition silicone

c. Polyether

d. Condensation silicone

8 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To reduce gamma II particule

b. Reduce surface microporosities

c. To prevent recurrent carries

d. To reduce discoloration

9 / 60

Clinical significance of smear layer :

a. Provides calcium for adhesion of composites

b. Bonded to tooth structure and prevents composite adhesion

c. Improve the strength of the composite

d. Increases the bonding action of the bonding agent

10 / 60

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

a. Tensile strength spherical high-copper

b. 1-hour compressive strength spherical high-copper

c. Creep irregular low-copper

d. Creep irregular high-copper

11 / 60

Ideal method firing of porcelain is by using 😕

a. Longer firing at low temperatures

b. Shorter firing at low temperatures

c. Longer firing at high temperatures

d. Shorter firing at higher temperatures

12 / 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

13 / 60

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

a. They have excellent tarnish and corrosion resistance

b. They can be heat treated

c. They cannot be soldered or welded

d. Their hardness is comparable to stainless steel

14 / 60

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

a. Type IV

b. Type III

c. Type I

d. Type II

15 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Decreases air voids in the restoration

b. Conserves the material

c. Increases surface smoothness

d. Increases strength and abrasive resistance

16 / 60

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

a. No evolution of any byproduct under all circumstances

b. Undetectable distortion on removal

c. Can be used in automixing devices

d. Dimensionally stable even after 1 week

17 / 60

Which of the following materials are used for dental implants ?

a. Cobalt and chromium alloys

b. Gold alloys

c. Metal alloys

d. Titanium

18 / 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. 30 ng Hg/m3 of air

c. 0.05 mg Hg/m3 of air

d. 100 ng Hg/m3 of air

19 / 60

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

a. Amalgam

b. Gold alloy

c. Ceramic

d. Silver alloys

20 / 60

In alginate impression the final gel is 😕

a. Sodium sulphate

b. Calcium sulphate

c. Calcium alginate

d. Sodium alginate

21 / 60

Adhesion in composites is due to 😕

a. Cohesion

b. Mechanical interlocking

c. True chemical bonding to tooth structure

d. Presence of smear layer

22 / 60

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

a. Knoop hardness test

b. Vichers hardness test

c. Rockwell hardness test

d. Brinell hardness test

23 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Condensation silicones

b. Polyether

c. Addition silicones

d. Polysulfides

24 / 60

The light from the visible light curing unit can cause 😕

a. Retinal damage

b. Iritis

c. Cataract

d. Corneal ulceration

25 / 60

The catalyst used for condensation silicones is 😕

a. Lead dioxide

b. Platinum

c. Stannous octoate

d. Oleic acid

26 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Benzoyl methyl ether

b. Toluidine

c. Bis-phenol-A

d. Camphoroquinone

27 / 60

Crystalline materials have 😕

a. No well-defined melting

b. Well-defined melting

c. No space lattice

d. Less stable space lattice

28 / 60

Most commonly used pit and fissure sealant is 😕

a. Bis-GMA resin

b. Filled acrylic

c. Unfilled acrylic

d. Polyurethane

29 / 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

30 / 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

31 / 60

Which of the following statements about laboratory composites are true ?

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

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

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

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

32 / 60

The desirable quality of porcelain is 😕

a. Translucency

b. Thermal expansion

c. Requirement of color

d. Toughness without brittleness

33 / 60

Following are the functions of impression compound except 😕

a. To record mucostatic impressions

b. To make impression of edentulous ridge

c. To make special tray for final impression

d. To make individual die impression with copper band

34 / 60

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

a. Platinum-aluminum-vanadium alloy

b. Titanium-aluminum-vanadium alloy

c. Titanium-platinum-aluminum alloy

d. Titanium-molybdenum-vanadium alloy

35 / 60

A cavity varnish used for lining the preparation for a dental amalgam restoration will :

a. Reduce early marginal leakage tooth structure

b. Provide strength of amalgam

c. Provide thermal insulation

d. Provide electrical insulation

36 / 60

When a mechanical device is used for mixing addition silicones 😕

a. Mixing time is long

b. More possibilities of contamination

c. Mixing time is reduced

d. There is no greater uniformity in proportioning and mixing

37 / 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

38 / 60

The main resin constituent of polishable composite resin is 😕

a. Urethane dimethacrylate

b. Polycaronate

c. Polymethyl methacrylate

d. Cyanoacrylate

39 / 60

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

a. Addition silicones

b. Condensation silicones

c. Polyethers

d. Polysulfides

40 / 60

Which has the highest viscoelastic property and requires more time to recover from deformation ?

a. Addition silicone

b. Polyether

c. Condensation silicone

d. Polysulfide

41 / 60

A glaze is placed over the finished composite restoration to 😕

a. To change the shade

b. To reduce surface porosities

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

d. No provide a better peripheral seal

42 / 60

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

a. Achieving complete polymerization

b. Compensating polymerization shrinkage

c. Providing strength to the restoration

d. Saving the application of bonding agent

43 / 60

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

a. Restorations are more brittle than low-copper versions

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

c. Produce excessive creep

d. Better corrosion resistance than low-copper dental amalgams

44 / 60

Working time of denture resin should be at least 😕

a. 20 minutes

b. 5 minutes

c. 15 minutes

d. 10 minutes

45 / 60

Commonly used filler in composite is 😕

a. Aluminum

b. Quartz

c. Glass

d. Colloidal silica

46 / 60

Noble metal alloys are classified according to their 😕

a. Dental function

b. Castability

c. Malleability

d. Melting temperature

47 / 60

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

a. High corrosion

b. Higher creep

c. Higher strength

d. Low corrosion

48 / 60

Once amalgamation has occurred, which of the following is true of mercury ?

a. Composite restorative resins

b. Can form at the surface of amalgam restorations if heated to 0° C

c. Is combined primarily with silver

d. Has the toxic properties of unreacted mercury

49 / 60

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

a. Vacuum up a spill immediately

b. Avoid polishing amalgams

c. Avoid touching freshly mixed amalgam

d. Sterilize amalgam scrap

50 / 60

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

a. Retarders

b. Reactors

c. Fillers

d. Accelerators

51 / 60

Which of the following composite is recommended for non stress bearing anterior restoration ?

a. Microfilled composites

b. Conventional composites

c. Hybrid composites

d. Small particles

52 / 60

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

a. Lowest strain in compression

b. Stiffness of the material

c. Shrinkage of material

d. Increased strain rate on unset material

53 / 60

Which one 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

54 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It provides luster to the pattern

b. It is harder and has less flow

c. It has low melting temperature

d. It is sticky

55 / 60

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

a. Increased solubility of the resin

b. Subsequent oxidation of the tertiary amine

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

d. Decreased polymerization of the resin

56 / 60

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

a. Toughness

b. Hardness

c. Springiness

d. Brittleness

57 / 60

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

a. Cured for longer period

b. Not indicated

c. Restoration should be build in increments

d. Fifth generation bonding agent should be applied

58 / 60

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

a. 2 mm

b. 4 mm

c. 3 mm

d. 1 mm

59 / 60

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

a. Sn-Hg

b. Ag-Su

c. Cu-Sn

d. Ag-Hg

60 / 60

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

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

b. Artificial acrylic teeth are attached

c. They are attached to natural teeth with cements,

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

Your score is

The average score is 61%

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