Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can not lead to cleaned property

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

c. It can be cleaned properly

d. It can not lead to fungal growth

2 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Corrosion decreases

b. Compressive strength decreases

c. Tensile strength increases

d. Corrosion increases

3 / 60

Following are the functions of impression compound except 😕

a. To record mucostatic impressions

b. To make individual die impression with copper band

c. To make impression of edentulous ridge

d. To make special tray for final impression

4 / 60

Which of the following statements apply to the packable composites ?

a. They are radiolucent.

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

c. Radiopaque

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

5 / 60

In dental plaster the main ingredient is 😕

a. Calcium anhydrate

b. Calcium sulfate dehydrate

c. Calcium phosphate

d. Calcium sulfate hemihydarate

6 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Benzoyl methyl ether

b. Camphoroquinone

c. Bis-phenol-A

d. Toluidine

7 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Polysulfides

b. Polyether

c. Addition silicones

d. Condensation silicones

8 / 60

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

a. Transosteal frames

b. Intramucosal frames

c. Endosseus implants

d. Subperiosteal

9 / 60

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

a. 4 mm

b. 3 mm

c. 1 mm

d. 2 mm

10 / 60

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

a. Flexibility

b. Impact strength

c. Toughness

d. Resilience

11 / 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

12 / 60

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

a. Polysulfide

b. Polyether

c. Addition silicone

d. Condensation silicone

13 / 60

Potato starch is contained in which impression material ?

a. Impression compound

b. Impression plaster

c. Agar agar

d. Potassium sulfate

14 / 60

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

a. Condensation silicones

b. Polyether

c. Polysulfides

d. Addition silicones

15 / 60

Which of the following is the best choice of restorative material to achieve moderate to high strength, fluorite release, and esthetics ?

a. Glass ionomer

b. Hybrid ionomer

c. Composite

d. Compomer

16 / 60

Porosity in denture base resins can be due to 😕

a. Well flasking of wax pattern

b. Applying sufficient pressure during polymerization

c. Adequate mixing of liquid and powder components

d. Excess heating of resin above its boiling point

17 / 60

When a mechanical device is used for mixing addition silicones 😕

a. There is no greater uniformity in proportioning and mixing

b. More possibilities of contamination

c. Mixing time is reduced

d. Mixing time is long

18 / 60

Which of the following materials are used for dental implants ?

a. Titanium

b. Cobalt and chromium alloys

c. Gold alloys

d. Metal alloys

19 / 60

Bis-GMA is a reaction product of 😕

a. Bis-phenol-A and urethane dimethacrylate

b. Urethane dimethacrylate and glycidyl

c. Bis-phenol-A and methyl methacrylate

d. Bis-phenol-A and glycidyl methacrylate

20 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Will be shrink as a result of syneresis

b. Is an irreversible hydrocolloid impression material

c. May exhibit a fluid exudates on the surface as a result of imbibitions

d. Will take up water and expand if kept wet

21 / 60

Setting of plaster of Paris is a result of 😕

a. Solubility difference between hemihydrates and dehydrate

b. Interaction between hemihydrates and water

c. Loss of water from hemihydrates

d. Indirect interaction between hemihydrates

22 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, tin, copper and zinc

b. Silver, mercury, copper and zinc

c. Silver, mercury, copper and mercury

d. Silver, tin, palladium and zinc

23 / 60

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

a. Does not alter setting time

b. Decreases setting time

c. Depends on rate of mixing

d. Increases setting time

24 / 60

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

a. Colloidal silica

b. Lithium aluminum silicate

c. Barium glass

d. Quartz

25 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Facilitate mechanical bonding

b. Remove smear layer

c. Create tags

d. Provide more strenght

26 / 60

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

a. Amalgam

b. Composite resin

c. Gold alloy

d. Porcelain

27 / 60

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

a. Their hardness is comparable to stainless steel

b. They cannot be soldered or welded

c. They can be heat treated

d. They have excellent tarnish and corrosion resistance

28 / 60

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

a. No evolution of any byproduct under all circumstances

b. Can be used in automixing devices

c. Undetectable distortion on removal

d. Dimensionally stable even after 1 week

29 / 60

Amalgam is less prone to corrosion 😕

a. If it contains 4-6% of copper

b. If devoid of the gamma 2 phase

c. If it contains zinc

d. If it contains 25-27% of tin

30 / 60

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

a. Porcelain will crack on cooling

b. Porcelain will provide good shade

c. Porcelain will wear off

d. Porcelain will not bond with metal

31 / 60

Which of the following office conditions minimize the health hazard from spilled mercury ?

a. Baseboard heating

b. Floor carpeting

c. Amalgam scrap stored in a closed container

d. Wall carpeting

32 / 60

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

a. Cu-Sn

b. Ag-Sn

c. Sn-Hg

d. Ag-Hg

33 / 60

Hand instruments for composites are made of 😕

a. Titanium

b. Carbon steel

c. Stainless steel

d. Teflon-coated metal

34 / 60

Silver in the set amalgam alloy tends to have the following effect 😕

a. Decreases ductility

b. Produces contraction

c. Hydrolyzes the water if contaminated

d. Decreases the setting time

35 / 60

Binder in the phosphate investment is 😕

a. Magnesium oxide and monoammonium phosphate

b. Cristobalite

c. Phosphoric acid

d. Manganese dioxide

36 / 60

Which statements are true for bonding of amalgam to tooth structure ?

a. The most effective bonding agents contain copalite.

b. The use of amalgam bonding restores the strength of the clinical crown to its original condition.

c. The use of amalgam bonding reduces marginal leakage of amalgam restorations.

d. Shear bond strength using amalgam bonding to teeth in clinically proven to be as high as that for bonding composites to teeth.

37 / 60

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

a. Teratogenesis

b. Biocompatibility

c. Carcinogenesis

d. Iatrogenesis

38 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Bond between agar and alginate is not very strong

b. Difficult to manipulate

c. Maximum details are not produced

d. Cost factor is high

39 / 60

Regarding Knoop hardness number, which of the following material is closest to that of dentine (KHN 65) ?

a. Silicates

b. Amalgam

c. Pure gold

d. Composites

40 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Decreases air voids in the restoration

b. Increases strength and abrasive resistance

c. Increases surface smoothness

d. Conserves the material

41 / 60

The desirable quality of porcelain is 😕

a. Toughness without brittleness

b. Requirement of color

c. Translucency

d. Thermal expansion

42 / 60

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

a. Biocompatibility

b. Flow

c. Adhesion

d. Dimensional stability

43 / 60

The strain at which the plastic strain develops may be represented by 😕

a. Toughness, rigidity, resilience

b. Elastic limit, modulus of elasticity, tensile strength

c. Elastic limit, yield strength, proportional limit

d. Yield strength, tensile strength, toughness

44 / 60

In UV curing system the activator employed is 😕

a. Dibutyl phthalate

b. Methyl methacrylate

c. Hydroquinone

d. Benzoin methyl ether

45 / 60

Working time of denture resin should be at least 😕

a. 5 minutes

b. 10 minutes

c. 20 minutes

d. 15 minutes

46 / 60

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

a. Providing strength to the restoration

b. Achieving complete polymerization

c. Saving the application of bonding agent

d. Compensating polymerization shrinkage

47 / 60

The catalyst used for condensation silicones is 😕

a. Platinum

b. Stannous octoate

c. Lead dioxide

d. Oleic acid

48 / 60

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

a. Amalgam

b. Composite resin

c. Gold alloys

d. Ceramic

49 / 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. Mixing in a mortar and pestle

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

d. Triturating precapsulated alloy and mercury

50 / 60

Impression compound is characterized by 😕

a. Amorphous in nature with high thermal conductivity

b. Crystalline in nature with high thermal conductivity

c. Crystalline in nature with definite melting point

d. Amorphous in nature with low thermal conductivity

51 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Chromium oxide

b. Chromium carbide

c. Cobalt oxide

d. Ferric oxide

52 / 60

Polyether is different from other elastomers in the following aspects 😕

a. High stiffiness

b. Can not be used as light cure material

c. Low stiffness

d. Hydropholic in nature

53 / 60

Commonly used coloring agent in impression plaster is 😕

a. Alizarin red

b. Indigo dye

c. Congo red

d. Metallic oxide

54 / 60

The following statements about dental porcelains are true except 😕

a. Undergoes firing shrinkage

b. Undergoes discoloration

c. It is brittle in nature

d. Crystalline nature

55 / 60

Compared to lathe-cut alloy, spherical dental amalgam alloys 😕

a. Requires more mercury for trituration

b. Have longer setting time

c. Requires higher forces of condensation

d. Requires less amalgamation time

56 / 60

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

a. Springiness

b. Toughness

c. Hardness

d. Brittleness

57 / 60

Which of the following composites give rough surfaced finish ?

a. Conventional composites

b. Hybrid composites

c. Small particle filled composites

d. Microfilled composites

58 / 60

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

a. Higher creep

b. Higher strength

c. Low corrosion

d. High corrosion

59 / 60

Minimal thickness of base for adequate thermal insulation is 😕

a. 0.5 mm

b. 0.75 mm

c. 1 mm

d. 2 mm

60 / 60

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

a. It cannot be polished

b. It cause abrasion and wearing of opposing tooth surface

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

d. It has low affinity for resin matrix

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The average score is 48%

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