Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

The greatest amount of dimensional change after setting is exhibited by 😕

a. Addition silicones

b. Polysulfides

c. Condensation silicones

d. Polyethers

2 / 60

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

a. Spermitic and bees wax

b. Montan and Japan coco

c. Paraffin and microcrystalline wax

d. Carnauba and candellia

3 / 60

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

a. Flow

b. Biocompatibility

c. Adhesion

d. Dimensional stability

4 / 60

Setting time of alginate can be better controlled by 😕

a. Mixing time

b. Changing water: powder ratio

c. Temperature of water used of mixing

d. Chemical accelerators and retarders

5 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 10 seconds

b. Polyacrylic acid for 60 seconds

c. Phosphoric acid for 60 seconds

d. Phosphoric acid for 10 seconds

6 / 60

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

a. Temperature of vaporization

b. Latent heat

c. Fusion temperature

d. Specific temperature

7 / 60

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

a. It is a bio-inert material

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

c. This material in granular form and is difficult

d. It is produced in block or granula form

8 / 60

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

a. Composite restorative resins

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

c. Is combined primarily with silver

d. Has the toxic properties of unreacted mercury

9 / 60

The main function of zinc in amalgam is 😕

a. To increase the longevity of amalgam after setting

b. To increase the shelf-life of an amalgam

c. To prevent the creep

d. To produce delayed expansion

10 / 60

Greening effect of porcelain is due to 😕

a. Palladium

b. Golde

c. Platinum

d. Silver

11 / 60

Which of the following is called periphery wax ?

a. Beading wax

b. Bite registration wax

c. Sticky wax

d. Utility wax

12 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 45-600C

b. 100C higher than mouth temperature

c. 37-450C

d. Far below the oral temperature

13 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. Several times in air

b. Under compression

c. Under low temperature

d. After metal is tempered

14 / 60

Porosity in denture base resins can be due to 😕

a. Adequate mixing of liquid and powder components

b. Well flasking of wax pattern

c. Applying sufficient pressure during polymerization

d. Excess heating of resin above its boiling point

15 / 60

The byproduct in condensation silicones is 😕

a. Methyl alcohol

b. Ethyl alcohol

c. Butyl alcohol

d. Propyl alcohol

16 / 60

Which of the following materials are used for dental implants ?

a. Gold alloys

b. Cobalt and chromium alloys

c. Titanium

d. Metal alloys

17 / 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

18 / 60

When the gold content of gold alloys increases 😕

a. The hardness decrease

b. The corrosion resistance increases

c. The percentage elongation decrease

d. Ductility decrease

19 / 60

Which of the following uses a hardened steel ball indenting tool ?

a. Vichers hardness test

b. Rockwell hardness test

c. Knoop hardness test

d. Brinell hardness test

20 / 60

Which of the following material has a high coefficient of thermal expansion ?

a. Glass ionomer cement

b. Unfilled acrylic resin

c. Composite resin

d. Silicate cement

21 / 60

Metal has the following properties except 😕

a. All metals do not have same degrees of strength and plasticity

b. Metal is any element that ionizes positively in solution

c. Pure metals are not useful in dentistry

d. Electroplated silver and copper are used in dies

22 / 60

Which of the following polymer systems are used for the organic matrix in composites ?

a. Pheyl methacrylate

b. Poly (methyl methacrylate)

c. Bisphenol A-glycidyl methacrylate (Bis-GMA)

d. Polystyrene

23 / 60

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

a. Polysulfied

b. Polyvinyl siloxane

c. Polyether

d. Condensation silicone

24 / 60

Thermal conductivity is proportional to 😕

a. Type of metal

b. Area of conduction

c. Fusion temperature

d. Hardness of metal

25 / 60

Adhesion in composites is due to 😕

a. Presence of smear layer

b. True chemical bonding to tooth structure

c. Mechanical interlocking

d. Cohesion

26 / 60

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

a. Ag-Sn

b. Ag-Hg

c. Sn-Hg

d. Cu-Sn

27 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Lesser bony apposition

b. Presence of fibrous tissue

c. Prolonged healing time

d. Greater bony opposition

28 / 60

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

a. 1 mm

b. 3 mm

c. 2 mm

d. 4 mm

29 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Silver

b. Copper

c. Nickel

d. Cobalt

30 / 60

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

a. Diamond burs at low to medium speed

b. Carbide burs at low to medium speed

c. Carbide burs at high speed

d. Diamond burs at high speed

31 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It has low melting temperature

b. It provides luster to the pattern

c. It is harder and has less flow

d. It is sticky

32 / 60

For each property, list the amalgam type (irregular low-copper, admixed high-copper, and spherical high-copper ) that has the highest value?.

a. 1-hour compressive strength spherical high-copper

b. Creep irregular low-copper

c. Tensile strength spherical high-copper

d. Creep irregular high-copper

33 / 60

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

a. Low alkalinity

b. High alkalinity

c. No antibacterial action

d. No Protein lysing effect

34 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Will take up water and expand if kept wet

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

c. Will be shrink as a result of syneresis

d. Is an irreversible hydrocolloid impression material

35 / 60

Clinical significance of smear layer :

a. Bonded to tooth structure and prevents composite adhesion

b. Provides calcium for adhesion of composites

c. Improve the strength of the composite

d. Increases the bonding action of the bonding agent

36 / 60

Wrought metal 😕

a. Cannot be rendered corrosion resistant

b. Can be formed by working on a cast metal

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

d. Cannot be heat treated

37 / 60

Which of the following components acts as a refractory material in porcelain ?

a. Kaolin

b. Silica

c. Potash

d. Feldspar

38 / 60

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

a. Ceramic

b. Silver alloys

c. Amalgam

d. Gold alloy

39 / 60

Commonly used viscosity controller in composites is 😕

a. Methyl methacrylate

b. Polyurethanes

c. TEG-DMA

d. Bis-GAM

40 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Toluidine

b. Benzoyl methyl ether

c. Camphoroquinone

d. Bis-phenol-A

41 / 60

Gold with high percentage elongation is best for 😕

a. To revert sagging during firing

b. To remove metallic oxide

c. Increase the bond strength

d. To improve the castability

42 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Bond between agar and alginate is not very strong

b. Maximum details are not produced

c. Cost factor is high

d. Difficult to manipulate

43 / 60

Commonly used filler in composite is 😕

a. Aluminum

b. Colloidal silica

c. Glass

d. Quartz

44 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, tin, copper and zinc

b. Silver, mercury, copper and mercury

c. Silver, tin, palladium and zinc

d. Silver, mercury, copper and zinc

45 / 60

Nickel sensitivity in the general population is 😕

a. 3% for men

b. 11% for women

c. 3% for women

d. 1% in the overall population

46 / 60

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

a. Provide thermal insulation

b. Provide strength of amalgam

c. Reduce early marginal leakage tooth structure

d. Provide electrical insulation

47 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It is low in strength

b. It does not oxidize

c. Pure zinc has no application in dentistry

d. It is relatively soft and ductile

48 / 60

Resistance of a liquid to motion is called 😕

a. Springiness

b. Creep

c. Viscosity

d. Diffusion

49 / 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 sharp decrease in flow

d. Results in a marked expansion

50 / 60

In UV curing system the activator employed is 😕

a. Benzoin methyl ether

b. Dibutyl phthalate

c. Hydroquinone

d. Methyl methacrylate

51 / 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.

52 / 60

The product that is formed on the surface of the amalgam restoration and frequently result in discoloration is 😕

a. Oxide

b. Gamma I Phase

c. Gamma II Phase

d. Sulphide

53 / 60

Which of these statements are correct in terms of preparing a correctly triturated mass of amalgam ?

a. Dental amalgam is a mixture of silver alloys and mercury.

b. A correctly triturated mass is a smooth homogeneous, and dull.

c. An overmixed mass is removed readily from the capsule but is soupy in appearance.

d. An undertriturated mass is crumbly and dull.

54 / 60

Potato starch is contained in which impression material ?

a. Potassium sulfate

b. Impression compound

c. Agar agar

d. Impression plaster

55 / 60

The most commonly used implant type presently is 😕

a. Intramucosal implant

b. Transosteal implant

c. Endosseous

d. Subperiosteal

56 / 60

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

a. Pulp inflammation

b. Sagging of restoration

c. Secondary caries

d. Porosity in restoration

57 / 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. The base paste consists of polyether polymer

d. Aromatic sulfonate ester acts as a cross linking agent

58 / 60

The reason zinc oxide eugenol cement is used as a temporary restoration 😕

a. It has an obtudant effect

b. It does not form reparative dentin

c. It has poor tensile strength

d. It does not have anticariogenic activity

59 / 60

Alginate impression material deteriorates rapidly at 😕

a. Elevated temperature

b. Temperature does not cause any change in shelf-life

c. Normal room temperature

d. Low temperature

60 / 60

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

a. Not indicated

b. Cured for longer period

c. Restoration should be build in increments

d. Fifth generation bonding agent should be applied

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