Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

A cavity varnish used for lining the preparation for a dental amalgam restoration will :

a. Provide electrical insulation

b. Provide strength of amalgam

c. Provide thermal insulation

d. Reduce early marginal leakage tooth structure

2 / 60

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

a. Elastic limit, yield strength, proportional limit

b. Elastic limit, modulus of elasticity, tensile strength

c. Yield strength, tensile strength, toughness

d. Toughness, rigidity, resilience

3 / 60

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

a. Springiness

b. Toughness

c. Hardness

d. Brittleness

4 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Wash impression for edentulous patients

b. Dual impression for Partially edentulous patients

c. Surgical paste

d. As interocclusal record material

5 / 60

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

a. Temperature of vaporization

b. Fusion temperature

c. Specific temperature

d. Latent heat

6 / 60

Following are the functions of impression compound except 😕

a. To make impression of edentulous ridge

b. To record mucostatic impressions

c. To make special tray for final impression

d. To make individual die impression with copper band

7 / 60

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

a. Hybrid composites

b. Microfilled composites

c. Conventional composites

d. Small particles

8 / 60

Stearic acid in impression compound 😕

a. Reduces plasticity

b. Reduces flow

c. Reduces brittleness

d. Increase setting time

9 / 60

Gypsum investments should not be heated above 😕

a. 17000C

b. 7000C

c. 10000C

d. 4500C

10 / 60

A glaze is placed over the finished composite restoration to 😕

a. No provide a better peripheral seal

b. Create a rough surface that is less receptive to extrinsic stain and plaque retention

c. To change the shade

d. To reduce surface porosities

11 / 60

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

a. Silicate cement

b. Amalgam

c. Unfilled

d. Glass ionomer cement

12 / 60

Calcium hydroxide is used for 😕

a. Reinforce the restoration

b. To prevent recurrent caries

c. Reduce maginal leakage

d. Pulp capping

13 / 60

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

a. Fillers

b. Reactors

c. Retarders

d. Accelerators

14 / 60

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

a. 30 mg Hg/m3 of air

b. 0.05 mg Hg/m3 of air

c. 100 mg Hg/m3 of air

d. 0.04 mg Hg/m3 of air

15 / 60

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

a. Biocompatibility

b. Carcinogenesis

c. Teratogenesis

d. Iatrogenesis

16 / 60

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

a. Type I

b. Type IV

c. Type II

d. Type III

17 / 60

Binder in the phosphate investment is 😕

a. Cristobalite

b. Magnesium oxide and monoammonium phosphate

c. Phosphoric acid

d. Manganese dioxide

18 / 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

19 / 60

Nickel sensitivity in the general population is 😕

a. 11% for women

b. 3% for women

c. 1% in the overall population

d. 3% for men

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

c. They are radiolucent.

d. Radiopaque

21 / 60

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

a. The base paste consists of polyether polymer

b. Aromatic sulfonate ester acts as a cross linking agent

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

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

22 / 60

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

a. Carnauba and candellia

b. Montan and Japan coco

c. Spermitic and bees wax

d. Paraffin and microcrystalline wax

23 / 60

Which of the following statements about adhesion of composite restorations to tooth structure are true ?

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

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

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

d. Bonding is achieved to enamel by application of an acid etchant followed by application of a bonding agent and then the composites resin.

24 / 60

Working time of denture resin should be at least 😕

a. 15 minutes

b. 10 minutes

c. 20 minutes

d. 5 minutes

25 / 60

Which of the following metals currently are used in dental alloys ?

a. Gold

b. Waxe

c. Glass ionomer

d. Ceramic

26 / 60

Which of the following is called periphery wax ?

a. Sticky wax

b. Beading wax

c. Bite registration wax

d. Utility wax

27 / 60

Wrought metal 😕

a. Can be formed by pouring molten metal into a mold

b. Cannot be heat treated

c. Can be formed by working on a cast metal

d. Cannot be rendered corrosion resistant

28 / 60

Adhesion in composites is due to 😕

a. True chemical bonding to tooth structure

b. Mechanical interlocking

c. Presence of smear layer

d. Cohesion

29 / 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. Higher strength, high creep, low corrosion

d. Low strength, low creep, low corrosion

30 / 60

For proper wetting, contact angle should be ideally 😕

a. 00

b. 600

c. 900

d. 450

31 / 60

Crystal structures of metals are all the following except 😕

a. Circular

b. Cubic

c. Monoclinic

d. Tetragonal

32 / 60

KHN of enamel is 😕

a. 600

b. 100

c. 90-100

d. 300

33 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Compressive strength decreases

b. Tensile strength increases

c. Corrosion decreases

d. Corrosion increases

34 / 60

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

a. Low alkalinity

b. No Protein lysing effect

c. No antibacterial action

d. High alkalinity

35 / 60

Once amalgamation has occurred, which of the following is true of mercury ?

a. Is combined primarily with silver

b. Has the toxic properties of unreacted mercury

c. Can form at the surface of amalgam restorations if heated to 0° C

d. Composite restorative resins

36 / 60

All are properties of waxes except 😕

a. Solidification shrinkage

b. Creep

c. Flow

d. Plastic deformation

37 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, mercury, copper and mercury

b. Silver, tin, palladium and zinc

c. Silver, mercury, copper and zinc

d. Silver, tin, copper and zinc

38 / 60

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

a. Base plate wax

b. Sticky wax

c. Utility wax

d. Carding wax

39 / 60

For luting purpose, the film thickness should be 😕

a. ideally 100 μm

b. up to 75 μm

c. 25 μm or less

d. minimum 50 μm

40 / 60

The main advantage of composites compared to silicates cement is 😕

a. Color matching with the tooth structure is excellent

b. Coefficient of thermal expansion close to tooth structure

c. High modulus of resilience

d. Practically insoluble in oral fluids

41 / 60

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

a. Compressive stress

b. Shear stress

c. Impact stress

d. Tensile stress

42 / 60

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

a. Saving the application of bonding agent

b. Providing strength to the restoration

c. Compensating polymerization shrinkage

d. Achieving complete polymerization

43 / 60

The physical property measured in terms of the deformation of the structure per until dimensions is ?

a. Stress

b. Amorphous material

c. Space lattice

d. Strain

44 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Will be shrink as a result of syneresis

b. Will take up water and expand if kept wet

c. Is an irreversible hydrocolloid impression material

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

45 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 100C higher than mouth temperature

b. 37-450C

c. 45-600C

d. Far below the oral temperature

46 / 60

Excess composite from the labial surfaces can be removed by using 😕

a. Diamond burs at high speed

b. Carbide burs at high speed

c. Carbide burs at low to medium speed

d. Diamond burs at low to medium speed

47 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Increases strength and abrasive resistance

b. Increases surface smoothness

c. Decreases air voids in the restoration

d. Conserves the material

48 / 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 is the easiest method of removal

c. It decreases the time for syneresis to occur

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

49 / 60

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

a. Gold alloy

b. Composite resin

c. Amalgam

d. Porcelain

50 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Cobalt oxide

b. Chromium carbide

c. Ferric oxide

d. Chromium oxide

51 / 60

The main ingredient of casting waxes is 😕

a. Carnauba wax

b. Paraffin wax

c. Candellila wax

d. Gum dammar

52 / 60

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

a. Acrylic resin

b. Polydimethyl siloxane

c. Styrene-acrylonitrile

d. Ethyl silicate

53 / 60

In dental plaster the main ingredient is 😕

a. Calcium sulfate hemihydarate

b. Calcium sulfate dehydrate

c. Calcium phosphate

d. Calcium anhydrate

54 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It has low melting temperature

b. It is harder and has less flow

c. It provides luster to the pattern

d. It is sticky

55 / 60

The common characteristic for pit and fissure sealant composite resins, acrylic appliances and elastomeric impression materials is :

a. All of them should be heated before using

b. All of them are a result of secondary reaction

c. All of them can be employed as anterior filling materials

d. All of them are polymers

56 / 60

The catalyst used for condensation silicones is 😕

a. Oleic acid

b. Platinum

c. Stannous octoate

d. Lead dioxide

57 / 60

Gold with high percentage elongation is best for 😕

a. To improve the castability

b. Increase the bond strength

c. To remove metallic oxide

d. To revert sagging during firing

58 / 60

Which of the following statements about compomers are true ?

a. They typically are recommended for class II restorations.

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

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

d. They also are know as GIC

59 / 60

The main resin constituent of polishable composite resin is 😕

a. Cyanoacrylate

b. Polycaronate

c. Urethane dimethacrylate

d. Polymethyl methacrylate

60 / 60

Noble metal alloys are classified according to their 😕

a. Castability

b. Melting temperature

c. Malleability

d. Dental function

Your score is

The average score is 47%

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