Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

a. Polysulfide

b. Condensation silicone

c. Polyether

d. Addition silicone

2 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. Under low temperature

b. After metal is tempered

c. Under compression

d. Several times in air

3 / 60

Proportional limit is defined as :

a. The maximum stress that can be induced without permanent deformation

b. A deformation resulting from an applied load

c. The stress/strain ratio within the elastic limit in a structure

d. The maximum force required to cause a structure to break

4 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 37-450C

b. 100C higher than mouth temperature

c. Far below the oral temperature

d. 45-600C

5 / 60

Which of the following composites give rough surfaced finish ?

a. Small particle filled composites

b. Hybrid composites

c. Conventional composites

d. Microfilled composites

6 / 60

Glass ionomer cenment is not recommended for 😕

a. Class I restoration

b. Class III restoration

c. Class V restoration

d. Class IV resoration

7 / 60

Ideally, the set amalgam should do which of the following ?

a. Properties of amalgam

b. Expand greatly to provide marginal seal against the tooth

c. Shrink significantly to provide space for correction products to seal the margins

d. Have little dimensional change

8 / 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. Triturating precapsulated alloy and mercury

c. A cover over the mixing arms on a triturator

d. Mixing in a mortar and pestle

9 / 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 produced in block or granula form

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

10 / 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 II

d. Type I

11 / 60

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

a. Carding wax

b. Base plate wax

c. Utility wax

d. Sticky wax

12 / 60

The energy absorbed by a material when it is stressed to its proportional limit is 😕

a. Impact strength

b. Toughness

c. Flexibility

d. Resilience

13 / 60

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

a. Ag-Hg

b. Ag-Su

c. Cu-Sn

d. Sn-Hg

14 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Benzoyl methyl ether

b. Toluidine

c. Bis-phenol-A

d. Camphoroquinone

15 / 60

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

a. Compensating polymerization shrinkage

b. Providing strength to the restoration

c. Achieving complete polymerization

d. Saving the application of bonding agent

16 / 60

Stearic acid in impression compound 😕

a. Increase setting time

b. Reduces brittleness

c. Reduces flow

d. Reduces plasticity

17 / 60

Alginate impression material deteriorates rapidly at 😕

a. Temperature does not cause any change in shelf-life

b. Normal room temperature

c. Elevated temperature

d. Low temperature

18 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

a. When the material is glossy

b. Exactly after four minutes after kneading

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

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

19 / 60

For luting purpose, the film thickness should be 😕

a. up to 75 μm

b. ideally 100 μm

c. minimum 50 μm

d. 25 μm or less

20 / 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

21 / 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 electrical insulation

d. Provide thermal insulation

22 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Addition silicones

b. Polyether

c. Condensation silicones

d. Polysulfides

23 / 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

24 / 60

For proper wetting, contact angle should be ideally 😕

a. 900

b. 00

c. 600

d. 450

25 / 60

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

a. Condensation silicones

b. Polysulfides

c. Addition silicones

d. Polyether

26 / 60

The main resin constituent of polishable composite resin is 😕

a. Cyanoacrylate

b. Urethane dimethacrylate

c. Polymethyl methacrylate

d. Polycaronate

27 / 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

28 / 60

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

a. Paraffin and microcrystalline wax

b. Spermitic and bees wax

c. Montan and Japan coco

d. Carnauba and candellia

29 / 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

30 / 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

31 / 60

Contamination of zinc-containing amalgam by moisture during triturating or condensation :

a. Results in a sharp decrease in flow

b. Has no appreciable effect on properties except to the susceptibility to tarnish

c. Results in a marked expansion

d. Increases the setting time

32 / 60

Which of the following properties are higher for microhybrid composites than for microfilled composites ?

a. Thermal expansion

b. Water sorption

c. Polymerization shrinkage

d. Modulus of elasticity

33 / 60

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

a. Condensation silicones

b. Addition silicones

c. Polyethers

d. Polysulfides

34 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Cobalt

b. Nickel

c. Silver

d. Copper

35 / 60

Amalgam is less prone to corrosion 😕

a. If devoid of the gamma 2 phase

b. If it contains 25-27% of tin

c. If it contains zinc

d. If it contains 4-6% of copper

36 / 60

The main function of zinc in amalgam is 😕

a. To prevent the creep

b. To increase the longevity of amalgam after setting

c. To produce delayed expansion

d. To increase the shelf-life of an amalgam

37 / 60

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

a. They are attached to natural teeth with cements,

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

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

d. Artificial acrylic teeth are attached

38 / 60

Commonly used filler in composite is 😕

a. Colloidal silica

b. Glass

c. Quartz

d. Aluminum

39 / 60

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

a. Has a better reaction with zinc oxide

b. To increase setting time

c. Reduces burning sensation of paste

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

40 / 60

Resistance of a liquid to motion is called 😕

a. Creep

b. Springiness

c. Diffusion

d. Viscosity

41 / 60

The appropriate proportion of polymer to monomer component of dental resin by volume is generally 😕

a. 2:1

b. 3:1

c. 1:2

d. 1:3

42 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can be cleaned properly

b. It can not lead to fungal growth

c. It can not lead to cleaned property

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

43 / 60

Which of these statements are correct in terms of preparing a correctly triturated mass of amalgam ?

a. A correctly triturated mass is a smooth homogeneous, and dull.

b. Dental amalgam is a mixture of silver alloys and mercury.

c. An undertriturated mass is crumbly and dull.

d. An overmixed mass is removed readily from the capsule but is soupy in appearance.

44 / 60

Light source in the curing unit is usually 😕

a. Infra red bulb

b. Sun light

c. Tungsten halogen light bulb

d. Ultraviolet light bulb

45 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. Reduce surface microporosities

b. To prevent recurrent carries

c. To reduce discoloration

d. To reduce gamma II particule

46 / 60

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

a. Higher creep

b. High corrosion

c. Higher strength

d. Low corrosion

47 / 60

Greater ratio fo zinc oxide to eugenol will have the following effect on setting time 😕

a. Increases setting time

b. Does not alter setting time

c. Decreases setting time

d. Depends on rate of mixing

48 / 60

Which of these statements apply to the filler particles of composites ?

a. Microfilled composites contain more filler than all-purpose composites.

b. Microfilled

c. Microhybrid composites contain as much as 84% filler by weight.

d. All are correct

49 / 60

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

a. Vichers hardness test

b. Brinell hardness test

c. Rockwell hardness test

d. Knoop hardness test

50 / 60

A full crown on a maxillary anterior tooth may be restored with which of the following restorative materials ?

a. Amalgam

b. Ceramic

c. Gold alloys

d. Composite resin

51 / 60

In dental plaster the main ingredient is 😕

a. Calcium phosphate

b. Calcium anhydrate

c. Calcium sulfate dehydrate

d. Calcium sulfate hemihydarate

52 / 60

Which of the following initiator-accelerator systems is needed for a light-activated composite?

a. Organic acid-peroxide

b. Peroxide-amine

c. Diketone-amine

d. Organic acid-metal ion

53 / 60

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

a. Titanium-platinum-aluminum alloy

b. Titanium-molybdenum-vanadium alloy

c. Platinum-aluminum-vanadium alloy

d. Titanium-aluminum-vanadium alloy

54 / 60

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

a. Before light activation, the base and catalyst pastes are mixed.

b. Light from an argon laser will activate polymerization.

c. Exposure times of 2 to 3 seconds are needed for polymerization with visible light.

d. Lights with both blue and red wavelengths are equally effective for polymerization.

55 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Facilitate mechanical bonding

b. Create tags

c. Provide more strenght

d. Remove smear layer

56 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Packing

b. Deflasking

c. Curing

d. Polishing

57 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Cost factor is high

b. Maximum details are not produced

c. Difficult to manipulate

d. Bond between agar and alginate is not very strong

58 / 60

Porcelain denture teeth 😕

a. Are more resistant of abrasion than gold

b. Have higher coefficient of thermal expansion than resin teeth

c. Have decreased abrasion resistance than dentin

d. Are easy to grind and polish

59 / 60

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

a. Springiness

b. Toughness

c. Brittleness

d. Hardness

60 / 60

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

a. Retarders

b. Accelerators

c. Reactors

d. Fillers

Your score is

The average score is 42%

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