Biomaterial Test

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Biomaterial Test

1 / 60

Minimal thickness of base for adequate thermal insulation is 😕

a. 0.75 mm

b. 1 mm

c. 0.5 mm

d. 2 mm

2 / 60

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

a. 2:1

b. 1:3

c. 3:1

d. 1:2

3 / 60

When a mechanical device is used for mixing addition silicones 😕

a. Mixing time is long

b. There is no greater uniformity in proportioning and mixing

c. More possibilities of contamination

d. Mixing time is reduced

4 / 60

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

a. Porcelain

b. Amalgam

c. Gold alloy

d. Composite resin

5 / 60

The temperature at which a solid changes into liquid is called 😕

a. Latent heat

b. Specific temperature

c. Fusion temperature

d. Temperature of vaporization

6 / 60

The restorative material used to restore a small portion of an anterior tooth should have which of the following properties ?

a. Esthetics

b. Amalgam

c. Ease of casting

d. High strength

7 / 60

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

a. Ceramic

b. Amalgam

c. Composite resin

d. Gold alloys

8 / 60

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

a. Expand greatly to provide marginal seal against the tooth

b. Properties of amalgam

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

d. Have little dimensional change

9 / 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 should be heated before using

d. All of them are polymers

10 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Ferric oxide

b. Cobalt oxide

c. Chromium carbide

d. Chromium oxide

11 / 60

Elgiloy arch wire is 😕

a. β-titanium arch wire

b. Cobalt-chromium-nickel alloy

c. Gold alloy

d. Optical fiber arch wire

12 / 60

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

a. Flexibility

b. Toughness

c. Resilience

d. Impact strength

13 / 60

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

a. Should be brittle

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

c. Should bond with dental porcelain

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

14 / 60

The function of gum dammar in inlay wax is 😕

a. To improve smoothness of pattern

b. No resistance to carving

c. No smoothness of pattern

d. Less strength to wax

15 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Silver

b. Cobalt

c. Nickel

d. Copper

16 / 60

The main function of zinc in amalgam is 😕

a. To increase the longevity of amalgam after setting

b. To produce delayed expansion

c. To prevent the creep

d. To increase the shelf-life of an amalgam

17 / 60

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

a. It is a bio-inert material

b. It is produced in block or granula form

c. This material in granular form and is difficult

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

18 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. To reduce gamma II particules

b. Condense the unattacked gamma I particles

c. Condense the unattacked gamma II particles

d. Condense the unattacked gamma particles

19 / 60

Setting of plaster of Paris is a result of 😕

a. Interaction between hemihydrates and water

b. Solubility difference between hemihydrates and dehydrate

c. Loss of water from hemihydrates

d. Indirect interaction between hemihydrates

20 / 60

Acrylic resins are used in which of the following ?

a. Posterior inlays

b. Denture bases

c. Anterior onlays

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

21 / 60

KHN of enamel is 😕

a. 90-100

b. 300

c. 100

d. 600

22 / 60

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

a. Carbone steal

b. They are attached to natural teeth with cements,

c. Artificial waxes teeth are attached

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

23 / 60

In dental plaster the main ingredient is 😕

a. Calcium anhydrate

b. Calcium sulfate dehydrate

c. Calcium sulfate hemihydarate

d. Calcium phosphate

24 / 60

When the gold content of gold alloys increases 😕

a. The corrosion resistance increases

b. The hardness decrease

c. The percentage elongation decrease

d. Ductility decrease

25 / 60

Binder in the phosphate investment is 😕

a. Cristobalite

b. Phosphoric acid

c. Manganese dioxide

d. Magnesium oxide and monoammonium phosphate

26 / 60

Adhesion in composites is due to 😕

a. Mechanical interlocking

b. True chemical bonding to tooth structure

c. Cohesion

d. Presence of smear layer

27 / 60

Inorganic phase in a composite matrix 😕

a. Increases the polymerization shrinkage

b. Decreases the mechanical strength

c. Increases the mechanical strength

d. Increases coefficient of thermal expansion

28 / 60

The following statements about dental porcelains are true except 😕

a. It is brittle in nature

b. Undergoes firing shrinkage

c. Undergoes discoloration

d. Crystalline nature

29 / 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

30 / 60

Noble metal alloys are classified according to their 😕

a. Melting temperature

b. Castability

c. Malleability

d. Dental function

31 / 60

The constituent that acts as a binder in the investment is 😕

a. Gypsum

b. Water

c. Quartz

d. Silica

32 / 60

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

a. Silver alloys

b. Amalgam

c. Gold alloy

d. Ceramic

33 / 60

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

a. Amalgam

b. Gold alloy

c. Composite resin

d. Metal

34 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Reduce porosity

b. Get a smooth surface

c. Regulate the setting time

d. Increase strength

35 / 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. 1 mm

d. 3 mm

36 / 60

Montan waxes have the following properties except 😕

a. Obtained by extraction from lignite

b. Have low melting points of 42oC

c. Hard, brittle and lustrous

d. Are mineral waxes

37 / 60

A measure of ductility of a material is referred to as 😕

a. Proportional limit

b. Percentage elongation

c. Flexibility

d. Yield strength

38 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

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

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

c. When the material is glossy

d. Exactly after four minutes after kneading

39 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Decreases air voids in the restoration

b. Conserves the material

c. Increases strength and abrasive resistance

d. Increases surface smoothness

40 / 60

The desirable quality of porcelain is 😕

a. Requirement of color

b. Toughness without brittleness

c. Translucency

d. Thermal expansion

41 / 60

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

a. Sn-Hg

b. Ag-Sn

c. Ag-Hg

d. Cu-Sn

42 / 60

In UV curing system the activator employed is 😕

a. Hydroquinone

b. Dibutyl phthalate

c. Benzoin methyl ether

d. Methyl methacrylate

43 / 60

Which of the following statements apply to the packable composites ?

a. Their depth of cure allows bulk polymerization, which has been shown to be clinically effective.

b. Radiopaque

c. Their wear rate is low (3.5 μm/year). Which is similar to that of amalgam.

d. They are radiolucent.

44 / 60

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

a. Type III

b. Type II

c. Type IV

d. Type I

45 / 60

For luting purpose, the film thickness should be 😕

a. minimum 50 μm

b. ideally 100 μm

c. 25 μm or less

d. up to 75 μm

46 / 60

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

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

b. Aromatic sulfonate ester acts as a cross linking agent

c. The base paste consists of polyether polymer

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

47 / 60

Light source in the curing unit is usually 😕

a. Tungsten halogen light bulb

b. Sun light

c. Ultraviolet light bulb

d. Infra red bulb

48 / 60

Glass ionomer cenment is not recommended for 😕

a. Class I restoration

b. Class IV resoration

c. Class V restoration

d. Class III restoration

49 / 60

Ideal method firing of porcelain is by using 😕

a. Shorter firing at low temperatures

b. Longer firing at high temperatures

c. Shorter firing at higher temperatures

d. Longer firing at low temperatures

50 / 60

The most accurate polysulfide impressions are made by using a custom acrylic tray because 😕

a. Custom tray made of plastic material ensures a uniform thickness of impression material

b. More pressure can be applied during impression making

c. It can hold more amount of impression material

d. The tray does not distort during impression making

51 / 60

The light from the visible light curing unit can cause 😕

a. Cataract

b. Iritis

c. Retinal damage

d. Corneal ulceration

52 / 60

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

a. Sagging of restoration

b. Secondary caries

c. Porosity in restoration

d. Pulp inflammation

53 / 60

The most commonly used implant type presently is 😕

a. Intramucosal implant

b. Subperiosteal

c. Transosteal implant

d. Endosseous

54 / 60

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

a. Accelerators

b. Retarders

c. Fillers

d. Reactors

55 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Addition silicones

b. Polyether

c. Polysulfides

d. Condensation silicones

56 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Zinc silicophoshpate

b. Calcum hydroxide

c. Zinc phosphate

d. Polycardoxylate

57 / 60

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

a. Polysulfides

b. Addition silicones

c. Condensation silicones

d. Polyether

58 / 60

The main use of zinc oxide eugenol cement is 😕

a. Temporary restoration

b. Base

c. Indirect pulp capping agent

d. Permanent restoration

59 / 60

Side effects and complications resulting from treatment by a physician or dentist is 😕

a. Carcinogenesis

b. Teratogenesis

c. Iatrogenesis

d. Biocompatibility

60 / 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

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