Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

a. Increases the setting time

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

c. Results in a marked expansion

d. Results in a sharp decrease in flow

2 / 60

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

a. Secondary caries

b. Porosity in restoration

c. Sagging of restoration

d. Pulp inflammation

3 / 60

In UV curing system the activator employed is 😕

a. Methyl methacrylate

b. Hydroquinone

c. Benzoin methyl ether

d. Dibutyl phthalate

4 / 60

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

a. Decreased polymerization of the resin

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

c. Increased solubility of the resin

d. Subsequent oxidation of the tertiary amine

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

c. Aromatic sulfonate ester acts as a cross linking agent

d. The base paste consists of polyether polymer

6 / 60

The cracks formed on the ceramic during cooling because 😕

a. The inner layer cools more rapidly than the outer layer

b. The outer layer cools more rapidly than the interior

c. Due to external forces

d. The cooling of the outer and the inner layer occurs at the same rate

7 / 60

The physical properties most desirable in set amalgam are which of the following ?

a. Higher strength, low creep, low corrosion

b. Higher strength, high creep, high corrosion

c. Low strength, low creep, low corrosion

d. Higher strength, high creep, low corrosion

8 / 60

Cobalt-chromium alloy is mostly used for the construction of 😕

a. Intramucosal frames

b. Transosteal frames

c. Endosseus implants

d. Subperiosteal

9 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Surgical paste

b. As interocclusal record material

c. Dual impression for Partially edentulous patients

d. Wash impression for edentulous patients

10 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Packing

b. Deflasking

c. Curing

d. Polishing

11 / 60

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

a. Condensation silicone

b. Polyether

c. Polysulfide

d. Addition silicone

12 / 60

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

a. Not indicated

b. Fifth generation bonding agent should be applied

c. Cured for longer period

d. Restoration should be build in increments

13 / 60

Calcium hydroxide is used for 😕

a. Pulp capping

b. Reduce maginal leakage

c. Reinforce the restoration

d. To prevent recurrent caries

14 / 60

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

a. Ceramic

b. Amalgam

c. Gold alloys

d. Composite resin

15 / 60

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

a. It is more sensitive to oxygen inhibitors

b. It takes more time for curing

c. It has more working time available

d. It has not more working time available

16 / 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

17 / 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 high speed

d. Carbide burs at low to medium speed

18 / 60

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

a. It can hold more amount of impression material

b. The tray does not distort during impression making

c. More pressure can be applied during impression making

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

19 / 60

Which of the following represents the maximum safe concentration of mercury vapor in the breathing zone for a 40-hour workweek ?

a. 30 ng Hg/m3 of air

b. All are corrects

c. 0.05 mg Hg/m3 of air

d. 100 ng Hg/m3 of air

20 / 60

The light from the visible light curing unit can cause 😕

a. Iritis

b. Cataract

c. Corneal ulceration

d. Retinal damage

21 / 60

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

a. Latent heat

b. Fusion temperature

c. Specific temperature

d. Temperature of vaporization

22 / 60

The main resin constituent of polishable composite resin is 😕

a. Polymethyl methacrylate

b. Cyanoacrylate

c. Urethane dimethacrylate

d. Polycaronate

23 / 60

When a mechanical device is used for mixing addition silicones 😕

a. There is no greater uniformity in proportioning and mixing

b. Mixing time is long

c. More possibilities of contamination

d. Mixing time is reduced

24 / 60

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

a. Adhesion

b. Flow

c. Biocompatibility

d. Dimensional stability

25 / 60

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

a. Utility wax

b. Base plate wax

c. Sticky wax

d. Carding wax

26 / 60

Most commonly used pit and fissure sealant is 😕

a. Unfilled acrylic

b. Bis-GMA resin

c. Filled acrylic

d. Polyurethane

27 / 60

Which of the following statements is true regarding zinc phosphate cement ?

a. Has an obtudant effect on the pulp

b. The least irritant to the pulp

c. Is used as a permanent restorative material in adults

d. Is the oldest luting agent

28 / 60

Which of the following statements about compomers are true ?

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

b. They also are know as GIC

c. They typically are recommended for class II restorations.

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

29 / 60

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

a. It is produced in block or granula form

b. It is a bio-inert material

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

d. This material in granular form and is difficult

30 / 60

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

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

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

c. All are correct

d. Microfilled

31 / 60

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

a. Polyether

b. Polyvinyl siloxane

c. Polysulfied

d. Condensation silicone

32 / 60

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

a. 1:2

b. 3:1

c. 1:3

d. 2:1

33 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Camphoroquinone

b. Toluidine

c. Benzoyl methyl ether

d. Bis-phenol-A

34 / 60

Acrylic resins are used in which of the following ?

a. Denture bases

b. Posterior inlays

c. Anterior onlays

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

35 / 60

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

a. Ag-Su

b. Sn-Hg

c. Ag-Hg

d. Cu-Sn

36 / 60

Gypsum investments should not be heated above 😕

a. 10000C

b. 4500C

c. 7000C

d. 17000C

37 / 60

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

a. Toughness

b. Springiness

c. Brittleness

d. Hardness

38 / 60

Setting of plaster of Paris is a result of 😕

a. Interaction between hemihydrates and water

b. Indirect interaction between hemihydrates

c. Loss of water from hemihydrates

d. Solubility difference between hemihydrates and dehydrate

39 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Bonding between coupling agent and filler

b. Adhesive bonding between matrix and filler

c. Bonding with tooth structure

d. Bonding between coupling agent and tooth structure

40 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 10 seconds

b. Phosphoric acid for 10 seconds

c. Polyacrylic acid for 60 seconds

d. Phosphoric acid for 60 seconds

41 / 60

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

a. Composite resin

b. Glass ionomer

c. Amalgam

d. Acrylic resin

42 / 60

The fluoride release from glass ionomer cement is 😕

a. 0.005 mg during the first week

b. 0.75 mg during the first week

c. 0.0005 mg during the first month

d. 0.075 mg during the first month

43 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Facilitate mechanical bonding

b. Provide more strenght

c. Remove smear layer

d. Create tags

44 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Polyether

b. Polysulfides

c. Addition silicones

d. Condensation silicones

45 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Ferric oxide

b. Chromium carbide

c. Chromium oxide

d. Cobalt oxide

46 / 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. Proportioning mercury and alloy into a friction-fit capsule

d. A cover over the mixing arms on a triturator

47 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

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

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

c. When the material is glossy

d. Exactly after four minutes after kneading

48 / 60

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

a. Hybrid composites

b. Conventional composites

c. Small particles

d. Microfilled composites

49 / 60

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

a. Type I

b. Type II

c. Type III

d. Type IV

50 / 60

Which of the following is recommended as an adhesive to trays with polysulfides ?

a. Polydimethyl siloxane

b. Ethyl silicate

c. Styrene-acrylonitrile

d. Acrylic resin

51 / 60

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

a. Amalgam

b. Gold alloy

c. Composite resin

d. Porcelain

52 / 60

A potentially toxic element in base metal alloys is 😕

a. Boron

b. Molybdenum

c. Beryllium

d. Magnesium

53 / 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

54 / 60

For proper wetting, contact angle should be ideally 😕

a. 900

b. 600

c. 00

d. 450

55 / 60

Resistance of a liquid to motion is called 😕

a. Creep

b. Springiness

c. Diffusion

d. Viscosity

56 / 60

In an alloy oxygen scavenger is 😕

a. Copper

b. Palladium

c. Silver

d. Zinc

57 / 60

Which of the following base is contraindicated for composites ?

a. Calcium hydroxide

b. Zinc phosphate

c. Zinc oxide eugenol

d. Glass ionomer cement

58 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can not lead to fungal growth

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

c. It can not lead to cleaned property

d. It can be cleaned properly

59 / 60

Materials having coefficient of thermal expansion close to the tooth structure 😕

a. Glass ionomer cement

b. Silicate cement

c. Amalgam

d. Unfilled

60 / 60

Light source in the curing unit is usually 😕

a. Ultraviolet light bulb

b. Sun light

c. Tungsten halogen light bulb

d. Infra red bulb

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The average score is 48%

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