Biomaterial Test

5 votes, 5 avg

164

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Biomaterial Test

1 / 60

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

a. Silicate cement

b. Glass ionomer cement

c. Unfilled acrylic resin

d. Composite resin

2 / 60

A direct restorative material used frequently to restore a portion of a posterior tooth that is subject to large biting forces would possess which of the following properties ?

a. Ease of casting

b. High strength

c. Thermal insulation

d. Esthetics

3 / 60

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

a. Condensation silicone

b. Addition silicone

c. Polyether

d. Polysulfide

4 / 60

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

a. Gold alloy

b. Metal

c. Composite resin

d. Amalgam

5 / 60

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

a. Waxe

b. Ceramic

c. Gold

d. Glass ionomer

6 / 60

KHN of enamel is 😕

a. 90-100

b. 100

c. 300

d. 600

7 / 60

In a porcelain fused to metal restoration, the porcelain is-bonded to metal by 😕

a. Chemico-mechenical bonding

b. High malleafility of metal

c. Hight ductility of metal

d. Chemical bonding

8 / 60

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

a. Mixing in a mortar and pestle

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

c. A cover over the mixing arms on a triturator

d. Triturating precapsulated alloy and mercury

9 / 60

Greening effect of porcelain is due to 😕

a. Golde

b. Palladium

c. Silver

d. Platinum

10 / 60

Stearic acid in impression compound 😕

a. Reduces plasticity

b. Reduces flow

c. Reduces brittleness

d. Increase setting time

11 / 60

Most commonly used pit and fissure sealant is 😕

a. Unfilled acrylic

b. Filled acrylic

c. Bis-GMA resin

d. Polyurethane

12 / 60

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

a. It is the easiest method of removal

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

c. It decreases the time for syneresis to occur

d. Faster rate of removal increases the yield strength

13 / 60

Metal has the following properties except 😕

a. Pure metals are not useful in dentistry

b. Metal is any element that ionizes positively in solution

c. Electroplated silver and copper are used in dies

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

14 / 60

Of the four types of gold casting alloys, the most commonly used for crowns and bridges is 😕

a. Type II

b. Type III

c. Type IV

d. Type I

15 / 60

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

a. Composite resin

b. Amalgam

c. Porcelain

d. Gold alloy

16 / 60

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

a. Silver alloys

b. Amalgam

c. Gold alloy

d. Ceramic

17 / 60

Calcium hydroxide is used for 😕

a. Pulp capping

b. Reduce maginal leakage

c. Reinforce the restoration

d. To prevent recurrent caries

18 / 60

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

a. Ceramic

b. Composite restorative resins

c. Gold alloys

d. Acrylic resin

19 / 60

Which of the following properties are higher for microhybrid composites than for microfilled composites ?

a. Water sorption

b. Modulus of elasticity

c. Thermal expansion

d. Polymerization shrinkage

20 / 60

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

a. Polystyrene

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

c. Poly (methyl methacrylate)

d. Pheyl methacrylate

21 / 60

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

a. Depends on rate of mixing

b. Decreases setting time

c. Does not alter setting time

d. Increases setting time

22 / 60

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

a. Carnauba and candellia

b. Spermitic and bees wax

c. Paraffin and microcrystalline wax

d. Montan and Japan coco

23 / 60

Crystalline materials have 😕

a. Less stable space lattice

b. No well-defined melting

c. No space lattice

d. Well-defined melting

24 / 60

In dental plaster the main ingredient is 😕

a. Calcium anhydrate

b. Calcium phosphate

c. Calcium sulfate dehydrate

d. Calcium sulfate hemihydarate

25 / 60

Chemically cured resin shrinks:?

a. Away from the light source

b. Towards the center of bulk of material

c. On the surface only

d. On the base only

26 / 60

Porosity in denture base resins can be due to 😕

a. Well flasking of wax pattern

b. Excess heating of resin above its boiling point

c. Applying sufficient pressure during polymerization

d. Adequate mixing of liquid and powder components

27 / 60

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

a. Ethyl silicate

b. Acrylic resin

c. Styrene-acrylonitrile

d. Polydimethyl siloxane

28 / 60

Commonly used filler in composite is 😕

a. Quartz

b. Glass

c. Colloidal silica

d. Aluminum

29 / 60

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

a. Springiness

b. Toughness

c. Brittleness

d. Hardness

30 / 60

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

a. Increased solubility of the resin

b. Decreased polymerization of the resin

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

d. Subsequent oxidation of the tertiary amine

31 / 60

Wrought metal 😕

a. Cannot be heat treated

b. Can be formed by working on a cast metal

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

d. Cannot be rendered corrosion resistant

32 / 60

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

a. More pressure can be applied during impression making

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

c. The tray does not distort during impression making

d. It can hold more amount of impression material

33 / 60

Light source in the curing unit is usually 😕

a. Ultraviolet light bulb

b. Tungsten halogen light bulb

c. Sun light

d. Infra red bulb

34 / 60

Binder in the phosphate investment is 😕

a. Magnesium oxide and monoammonium phosphate

b. Manganese dioxide

c. Phosphoric acid

d. Cristobalite

35 / 60

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

a. Expand greatly to provide marginal seal against the tooth

b. Have little dimensional change

c. Properties of amalgam

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

36 / 60

Porcelain denture teeth 😕

a. Are easy to grind and polish

b. Have higher coefficient of thermal expansion than resin teeth

c. Are more resistant of abrasion than gold

d. Have decreased abrasion resistance than dentin

37 / 60

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

a. Type IV

b. Type I

c. Type II

d. Type III

38 / 60

Which of the following sentences describes the construction of removable partial dentures ?

a. They are attached to natural teeth with cements,

b. Artificial waxes teeth are attached

c. They are removable and attached to teeth with clasps.

d. Carbone steal

39 / 60

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

a. Reduce early marginal leakage tooth structure

b. Provide thermal insulation

c. Provide strength of amalgam

d. Provide electrical insulation

40 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. Far below the oral temperature

b. 100C higher than mouth temperature

c. 37-450C

d. 45-600C

41 / 60

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

a. Polysulfied

b. Polyether

c. Polyvinyl siloxane

d. Condensation silicone

42 / 60

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

a. Higher strength, high creep, low corrosion

b. Low strength, low creep, low corrosion

c. Higher strength, high creep, high corrosion

d. Higher strength, low creep, low corrosion

43 / 60

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

a. Impact strength

b. Toughness

c. Flexibility

d. Resilience

44 / 60

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

a. It has not more working time available

b. It has more working time available

c. It takes more time for curing

d. It is more sensitive to oxygen inhibitors

45 / 60

Softening of impressing compound is best accomplished by 😕

a. Open flame

b. Water bath

c. Oil bath

d. Dry heat

46 / 60

The main use of zinc oxide eugenol cement is 😕

a. Base

b. Temporary restoration

c. Indirect pulp capping agent

d. Permanent restoration

47 / 60

The restorative material used to restore a small portion of an anterior tooth should have which of the following properties ?

a. Esthetics

b. Ease of casting

c. High strength

d. Amalgam

48 / 60

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

a. Fifth generation bonding agent should be applied

b. Restoration should be build in increments

c. Cured for longer period

d. Not indicated

49 / 60

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

a. Barium glass

b. Quartz

c. Colloidal silica

d. Lithium aluminum silicate

50 / 60

Nickel sensitivity in the general population is 😕

a. 3% for men

b. 1% in the overall population

c. 11% for women

d. 3% for women

51 / 60

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

a. Polysulfides

b. Addition silicones

c. Polyether

d. Condensation silicones

52 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Sintering

b. Vulcanizing

c. Fritting

d. Fusing

53 / 60

Bis-GMA is a reaction product of 😕

a. Bis-phenol-A and methyl methacrylate

b. Bis-phenol-A and glycidyl methacrylate

c. Bis-phenol-A and urethane dimethacrylate

d. Urethane dimethacrylate and glycidyl

54 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. Condense the unattacked gamma II particles

b. Condense the unattacked gamma I particles

c. To reduce gamma II particules

d. Condense the unattacked gamma particles

55 / 60

Acrylic resins are used in which of the following ?

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

b. Denture bases

c. Anterior onlays

d. Posterior inlays

56 / 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

57 / 60

Noble metal alloys are classified according to their 😕

a. Melting temperature

b. Malleability

c. Dental function

d. Castability

58 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It does not oxidize

b. Pure zinc has no application in dentistry

c. It is low in strength

d. It is relatively soft and ductile

59 / 60

Oil of clove is sometimes used in preference to eugenal in ZOE paste because :

a. Reduces burning sensation of paste

b. It increases mixing property of paste and therefore improves impression recorded

c. Has a better reaction with zinc oxide

d. To increase setting time

60 / 60

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

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

b. All of them should be heated before using

c. All of them are a result of secondary reaction

d. All of them are polymers

Your score is

The average score is 86%

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