Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 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. 0.04 mg Hg/m3 of air

c. 100 mg Hg/m3 of air

d. 0.05 mg Hg/m3 of air

2 / 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.

3 / 60

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

a. The most effective bonding agents contain copalite.

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

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

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

4 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Packing

b. Deflasking

c. Polishing

d. Curing

5 / 60

Which of the following mixing methods permits the escape of dental amalgam mercury vapor ?

a. Triturating precapsulated alloy and mercury

b. A cover over the mixing arms on a triturator

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

d. Mixing in a mortar and pestle

6 / 60

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

a. Brinell hardness test

b. Vichers hardness test

c. Knoop hardness test

d. Rockwell hardness test

7 / 60

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

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

b. Have little dimensional change

c. Properties of amalgam

d. Expand greatly to provide marginal seal against the tooth

8 / 60

A glaze is placed over the finished composite restoration to 😕

a. To change the shade

b. To reduce surface porosities

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

d. No provide a better peripheral seal

9 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. Pure zinc has no application in dentistry

b. It does not oxidize

c. It is relatively soft and ductile

d. It is low in strength

10 / 60

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

a. Porcelain

b. Composite resin

c. Amalgam

d. Gold alloy

11 / 60

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

a. Percentage elongation

b. Proportional limit

c. Yield strength

d. Flexibility

12 / 60

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

a. Biocompatibility

b. Adhesion

c. Flow

d. Dimensional stability

13 / 60

Elgiloy arch wire is 😕

a. Gold alloy

b. β-titanium arch wire

c. Optical fiber arch wire

d. Cobalt-chromium-nickel alloy

14 / 60

Metal has the following properties except 😕

a. Electroplated silver and copper are used in dies

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

c. Metal is any element that ionizes positively in solution

d. Pure metals are not useful in dentistry

15 / 60

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

a. Polyvinyl siloxane

b. Condensation silicone

c. Polysulfied

d. Polyether

16 / 60

Strength of dental porcelain is dependent on 😕

a. No internal structure

b. Rough

c. Resistance to fusion

d. Composition

17 / 60

Which of the following materials are used for dental implants ?

a. Gold alloys

b. Titanium

c. Metal alloys

d. Cobalt and chromium alloys

18 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It is harder and has less flow

b. It is sticky

c. It provides luster to the pattern

d. It has low melting temperature

19 / 60

Distortion on removal from undercuts in addition silicones is very less due to 😕

a. Lowest strain in compression

b. Increased strain rate on unset material

c. Stiffness of the material

d. Shrinkage of material

20 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Bonding between coupling agent and filler

b. Bonding between coupling agent and tooth structure

c. Bonding with tooth structure

d. Adhesive bonding between matrix and filler

21 / 60

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

a. Higher strength, high creep, low corrosion

b. Higher strength, low creep, low corrosion

c. Higher strength, high creep, high corrosion

d. Low strength, low creep, low corrosion

22 / 60

Setting of plaster of Paris is a result of 😕

a. Loss of water from hemihydrates

b. Interaction between hemihydrates and water

c. Indirect interaction between hemihydrates

d. Solubility difference between hemihydrates and dehydrate

23 / 60

The most commonly employed alloy combination for use in implants is 😕

a. Titanium-molybdenum-vanadium alloy

b. Titanium-platinum-aluminum alloy

c. Titanium-aluminum-vanadium alloy

d. Platinum-aluminum-vanadium alloy

24 / 60

Impression plaster is a 😕

a. Reversible impression material

b. Thermoplastic material

c. Mucocompressive material

d. Mucostatic material

25 / 60

Nickel sensitivity in the general population is 😕

a. 1% in the overall population

b. 11% for women

c. 3% for men

d. 3% for women

26 / 60

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

a. Fusion temperature

b. Latent heat

c. Temperature of vaporization

d. Specific temperature

27 / 60

Setting time of alginate can be better controlled by 😕

a. Chemical accelerators and retarders

b. Mixing time

c. Temperature of water used of mixing

d. Changing water: powder ratio

28 / 60

Main disadvantage of denture base soft reliner is 😕

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

b. It can be cleaned properly

c. It can not lead to fungal growth

d. It can not lead to cleaned property

29 / 60

Which of the following is used to alter contour of impression trays ?

a. Boxing wax

b. Carding wax

c. Utility wax

d. Beading wax

30 / 60

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

a. Quartz

b. Lithium aluminum silicate

c. Barium glass

d. Colloidal silica

31 / 60

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

a. It has low affinity for resin matrix

b. It cause abrasion and wearing of opposing tooth surface

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

d. It cannot be polished

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

Calcium hydroxide is used for 😕

a. Reduce maginal leakage

b. Pulp capping

c. Reinforce the restoration

d. To prevent recurrent caries

34 / 60

Which one of the following is not true about high-copper dental amalgam restorations ?

a. Produce excessive creep

b. Better corrosion resistance than low-copper dental amalgams

c. Restorations are more brittle than low-copper versions

d. Contain both Sn and Ag in the composition as well

35 / 60

All are properties of waxes except 😕

a. Solidification shrinkage

b. Creep

c. Flow

d. Plastic deformation

36 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. To reduce gamma II particules

b. Condense the unattacked gamma II particles

c. Condense the unattacked gamma particles

d. Condense the unattacked gamma I particles

37 / 60

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

a. Stress

b. Strain

c. Space lattice

d. Amorphous material

38 / 60

Working time of denture resin should be at least 😕

a. 20 minutes

b. 10 minutes

c. 15 minutes

d. 5 minutes

39 / 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

40 / 60

Hydrocolloid impression should be removed from the mouth with a sharp jerk because 😕

a. It decreases the time for syneresis to occur

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

c. Faster rate of removal increases the yield strength

d. It is the easiest method of removal

41 / 60

In dental porcelains metallic oxides provide 😕

a. Provides refractile property and increases strength

b. Color but decreases the strength

c. Color and provides refractile property

d. Color and increases the strength

42 / 60

Crystalline materials have 😕

a. No well-defined melting

b. Less stable space lattice

c. No space lattice

d. Well-defined melting

43 / 60

Wrought metal 😕

a. Cannot be rendered corrosion resistant

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

c. Can be formed by working on a cast metal

d. Cannot be heat treated

44 / 60

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

a. Ag-Su

b. Ag-Hg

c. Sn-Hg

d. Cu-Sn

45 / 60

Biting force in the molar region ranges from 😕

a. 400-890 N

b. 600-1000 N

c. 1000-1300 N

d. 900-1000 N

46 / 60

The main advantage of composites compared to silicates cement is 😕

a. Practically insoluble in oral fluids

b. Coefficient of thermal expansion close to tooth structure

c. Color matching with the tooth structure is excellent

d. High modulus of resilience

47 / 60

Full denture bases are usually made from which of the following materials ?

a. Acrylic resin

b. Composite restorative resins

c. Ceramic

d. Gold alloys

48 / 60

The catalyst used for condensation silicones is 😕

a. Oleic acid

b. Lead dioxide

c. Platinum

d. Stannous octoate

49 / 60

The main resin constituent of polishable composite resin is 😕

a. Urethane dimethacrylate

b. Cyanoacrylate

c. Polycaronate

d. Polymethyl methacrylate

50 / 60

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

a. Type III

b. Type I

c. Type II

d. Type IV

51 / 60

Inorganic phase in a composite matrix 😕

a. Decreases the mechanical strength

b. Increases the mechanical strength

c. Increases the polymerization shrinkage

d. Increases coefficient of thermal expansion

52 / 60

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

a. Waxe

b. Gold

c. Glass ionomer

d. Ceramic

53 / 60

Porosity in denture base resins can be due to 😕

a. Excess heating of resin above its boiling point

b. Applying sufficient pressure during polymerization

c. Adequate mixing of liquid and powder components

d. Well flasking of wax pattern

54 / 60

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

a. Porosity in restoration

b. Secondary caries

c. Pulp inflammation

d. Sagging of restoration

55 / 60

For proper wetting, contact angle should be ideally 😕

a. 00

b. 900

c. 450

d. 600

56 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Will take up water and expand if kept wet

b. Will be shrink as a result of syneresis

c. Is an irreversible hydrocolloid impression material

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

57 / 60

Wet porcelain is condensed properly before firing to enhance all the properties except : ?

a. Reduce brittleness

b. Reduce firing shrinkage

c. Reduce porosity

d. increase strength

58 / 60

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

a. Ethyl silicate

b. Acrylic resin

c. Polydimethyl siloxane

d. Styrene-acrylonitrile

59 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Tensile strength increases

b. Compressive strength decreases

c. Corrosion decreases

d. Corrosion increases

60 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Copper

b. Silver

c. Nickel

d. Cobalt

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The average score is 42%

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