Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

Condensation of porcelain is done by all the methods except 😕

a. Vibration method

b. Brush addition technique

c. Ceramming method

d. Spatulation method

2 / 60

Hydrocolloid impression should be removed from the mouth with a sharp jerk because 😕

a. Faster rate of removal increases the yield strength

b. It decreases the time for syneresis to occur

c. The brush heap structure of a gel responds more favorably to a sudden force

d. It is the easiest method of removal

3 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can not lead to fungal growth

b. It can not lead to cleaned property

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

d. It can be cleaned properly

4 / 60

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

a. Ag-Sn

b. Cu-Sn

c. Sn-Hg

d. Ag-Hg

5 / 60

Impression compound is characterized by 😕

a. Crystalline in nature with definite melting point

b. Amorphous in nature with low thermal conductivity

c. Crystalline in nature with high thermal conductivity

d. Amorphous in nature with high thermal conductivity

6 / 60

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

a. Amalgam

b. Zinc phosphate

c. Direct resin-filling material

d. Silicate

7 / 60

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

a. Higher creep

b. Higher strength

c. High corrosion

d. Low corrosion

8 / 60

Gypsum investments should not be heated above 😕

a. 4500C

b. 7000C

c. 10000C

d. 17000C

9 / 60

Greening effect of porcelain is due to 😕

a. Silver

b. Golde

c. Platinum

d. Palladium

10 / 60

Which of the following statements about compomers are true ?

a. They typically are recommended for class II restorations.

b. They also are know as GIC

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

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

11 / 60

Crystal structures of metals are all the following except 😕

a. Monoclinic

b. Cubic

c. Circular

d. Tetragonal

12 / 60

The light from the visible light curing unit can cause 😕

a. Cataract

b. Iritis

c. Corneal ulceration

d. Retinal damage

13 / 60

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

a. Toughness

b. Impact strength

c. Flexibility

d. Resilience

14 / 60

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

a. Gold alloys

b. Composite resin

c. Ceramic

d. Amalgam

15 / 60

The desirable quality of porcelain is 😕

a. Translucency

b. Toughness without brittleness

c. Requirement of color

d. Thermal expansion

16 / 60

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

a. It cannot be polished

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

c. It cause abrasion and wearing of opposing tooth surface

d. It has low affinity for resin matrix

17 / 60

Silver has all the following characteristics except 😕

a. Silver points serve as a root canal filling material

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

c. Addition of palladium to silver increases corrosion

d. Whitens when added to alloys

18 / 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

19 / 60

Following are the functions of impression compound except 😕

a. To make individual die impression with copper band

b. To record mucostatic impressions

c. To make impression of edentulous ridge

d. To make special tray for final impression

20 / 60

The main advantage of composites compared to silicates cement is 😕

a. High modulus of resilience

b. Coefficient of thermal expansion close to tooth structure

c. Color matching with the tooth structure is excellent

d. Practically insoluble in oral fluids

21 / 60

Acrylic resins are used in which of the following ?

a. Anterior onlays

b. Posterior inlays

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

d. Denture bases

22 / 60

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

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

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

c. Light from an argon laser will activate polymerization.

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

23 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Corrosion increases

b. Tensile strength increases

c. Compressive strength decreases

d. Corrosion decreases

24 / 60

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

a. Polyether

b. Condensation silicones

c. Polysulfides

d. Addition silicones

25 / 60

Glass ionomer cenment is not recommended for 😕

a. Class V restoration

b. Class I restoration

c. Class IV resoration

d. Class III restoration

26 / 60

Resistance of a liquid to motion is called 😕

a. Creep

b. Viscosity

c. Diffusion

d. Springiness

27 / 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. High strength

b. Thermal insulation

c. Esthetics

d. Ease of casting

28 / 60

Ideal method firing of porcelain is by using 😕

a. Longer firing at high temperatures

b. Shorter firing at higher temperatures

c. Shorter firing at low temperatures

d. Longer firing at low temperatures

29 / 60

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

a. Results in a sharp decrease in flow

b. Results in a marked expansion

c. Increases the setting time

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

30 / 60

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

a. Heat temperature

b. Vapor temperature

c. Fusion temperature

d. Temperature of specificity

31 / 60

The catalyst used for condensation silicones is 😕

a. Lead dioxide

b. Platinum

c. Stannous octoate

d. Oleic acid

32 / 60

The type of stress to which dental amalgam is more resistant to 😕

a. Impact stress

b. Shear stress

c. Tensile stress

d. Compressive stress

33 / 60

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

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

b. Should be brittle

c. Should bond with dental porcelain

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

34 / 60

When a mechanical device is used for mixing addition silicones 😕

a. Mixing time is reduced

b. More possibilities of contamination

c. Mixing time is long

d. There is no greater uniformity in proportioning and mixing

35 / 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. Better corrosion resistance than low-copper dental amalgams

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

d. Produce excessive creep

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

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

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

37 / 60

In dental porcelains metallic oxides provide 😕

a. Color and provides refractile property

b. Color and increases the strength

c. Color but decreases the strength

d. Provides refractile property and increases strength

38 / 60

Which of the following properties of calcium hydroxide cement help in the formation of reparative dentin ?

a. No antibacterial action

b. No Protein lysing effect

c. High alkalinity

d. Low alkalinity

39 / 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 consists of copolymer of methylene oxide and tetrahydrofuran

c. The base paste consists of polyether polymer

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

40 / 60

Which of the following is called periphery wax ?

a. Bite registration wax

b. Sticky wax

c. Utility wax

d. Beading wax

41 / 60

Hand instruments for composites are made of 😕

a. Titanium

b. Teflon-coated metal

c. Stainless steel

d. Carbon steel

42 / 60

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

a. Sn-Hg

b. Ag-Su

c. Ag-Hg

d. Cu-Sn

43 / 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

44 / 60

The light-cured restorative resins have advantages over chemically activated restorative resins as 😕

a. It takes more time for curing

b. It has more working time available

c. It is more sensitive to oxygen inhibitors

d. It has not more working time available

45 / 60

Chemically cured resin shrinks:?

a. On the base only

b. On the surface only

c. Towards the center of bulk of material

d. Away from the light source

46 / 60

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

a. This material in granular form and is difficult

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

c. It is produced in block or granula form

d. It is a bio-inert material

47 / 60

Which of the following is used to alter contour of impression trays ?

a. Carding wax

b. Boxing wax

c. Beading wax

d. Utility wax

48 / 60

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

a. Saving the application of bonding agent

b. Compensating polymerization shrinkage

c. Achieving complete polymerization

d. Providing strength to the restoration

49 / 60

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

a. Flexibility

b. Toughness

c. Modulus of elasticity

d. Resilience

50 / 60

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

a. Barium glass

b. Lithium aluminum silicate

c. Colloidal silica

d. Quartz

51 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. Under compression

b. After metal is tempered

c. Several times in air

d. Under low temperature

52 / 60

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

a. 2:1

b. 1:3

c. 1:2

d. 3:1

53 / 60

Adhesion in composites is due to 😕

a. Mechanical interlocking

b. True chemical bonding to tooth structure

c. Presence of smear layer

d. Cohesion

54 / 60

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

a. A cover over the mixing arms on a triturator

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

c. Triturating precapsulated alloy and mercury

d. Mixing in a mortar and pestle

55 / 60

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

a. Water sorption

b. Thermal expansion

c. Polymerization shrinkage

d. Modulus of elasticity

56 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To reduce discoloration

b. To reduce gamma II particule

c. Reduce surface microporosities

d. To prevent recurrent carries

57 / 60

Potato starch is contained in which impression material ?

a. Impression compound

b. Potassium sulfate

c. Impression plaster

d. Agar agar

58 / 60

Elgiloy arch wire is 😕

a. Cobalt-chromium-nickel alloy

b. β-titanium arch wire

c. Gold alloy

d. Optical fiber arch wire

59 / 60

Clinical significance of smear layer :

a. Provides calcium for adhesion of composites

b. Increases the bonding action of the bonding agent

c. Bonded to tooth structure and prevents composite adhesion

d. Improve the strength of the composite

60 / 60

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

a. Polysulfied

b. Polyvinyl siloxane

c. Polyether

d. Condensation silicone

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