Biomaterial Test

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Biomaterial Test

1 / 60

Montan waxes have the following properties except 😕

a. Are mineral waxes

b. Hard, brittle and lustrous

c. Have low melting points of 42oC

d. Obtained by extraction from lignite

2 / 60

Which of the following statements about laboratory composites are true ?

a. Restorations prepared from laboratory composites typically are cemented with zinc phosphate cement.

b. Bridge prepared from laboratory composites require a metal substructure.

c. Curing using light, heat, and pressure increase the wear resistance.

d. Fiber reinforcement increases their strength but decrease their rigidity.

3 / 60

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

a. Carcinogenesis

b. Biocompatibility

c. Iatrogenesis

d. Teratogenesis

4 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Tensile strength increases

b. Corrosion increases

c. Corrosion decreases

d. Compressive strength decreases

5 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Cost factor is high

b. Maximum details are not produced

c. Bond between agar and alginate is not very strong

d. Difficult to manipulate

6 / 60

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

a. Flow

b. Adhesion

c. Biocompatibility

d. Dimensional stability

7 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Create tags

b. Remove smear layer

c. Provide more strenght

d. Facilitate mechanical bonding

8 / 60

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

a. 1 mm

b. 4 mm

c. 3 mm

d. 2 mm

9 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. Condense the unattacked gamma II particles

b. To reduce gamma II particules

c. Condense the unattacked gamma particles

d. Condense the unattacked gamma I particles

10 / 60

The appropriate proportion of polymer to monomer component of dental resin by volume is generally 😕

a. 2:1

b. 1:3

c. 1:2

d. 3:1

11 / 60

Most commonly used pit and fissure sealant is 😕

a. Polyurethane

b. Filled acrylic

c. Bis-GMA resin

d. Unfilled acrylic

12 / 60

Dental personnel can do which one of the following to limit their exposure to mercury ?

a. Sterilize amalgam scrap

b. Vacuum up a spill immediately

c. Avoid touching freshly mixed amalgam

d. Avoid polishing amalgams

13 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Get a smooth surface

b. Reduce porosity

c. Increase strength

d. Regulate the setting time

14 / 60

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

a. Rockwell hardness test

b. Vichers hardness test

c. Knoop hardness test

d. Brinell hardness test

15 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Alginate

b. Zinc oxide eugenol impression paste

c. Polyvinyl siloxane

d. Polyether

16 / 60

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

a. Paraffin and microcrystalline wax

b. Montan and Japan coco

c. Carnauba and candellia

d. Spermitic and bees wax

17 / 60

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

a. Provide electrical insulation

b. Provide thermal insulation

c. Provide strength of amalgam

d. Reduce early marginal leakage tooth structure

18 / 60

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

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

b. It decreases the time for syneresis to occur

c. It is the easiest method of removal

d. Faster rate of removal increases the yield strength

19 / 60

Pick out the incorrect statement regarding alginate impressions 😕

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

b. Will take up water and expand if kept wet

c. Will be shrink as a result of syneresis

d. Is an irreversible hydrocolloid impression material

20 / 60

The byproduct in condensation silicones is 😕

a. Butyl alcohol

b. Propyl alcohol

c. Methyl alcohol

d. Ethyl alcohol

21 / 60

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

a. Transosteal frames

b. Subperiosteal

c. Intramucosal frames

d. Endosseus implants

22 / 60

Gypsum investments should not be heated above 😕

a. 7000C

b. 17000C

c. 4500C

d. 10000C

23 / 60

Calcium hydroxide is used for 😕

a. Reduce maginal leakage

b. To prevent recurrent caries

c. Pulp capping

d. Reinforce the restoration

24 / 60

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

a. Lowest strain in compression

b. Shrinkage of material

c. Stiffness of the material

d. Increased strain rate on unset material

25 / 60

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

a. Tensile stress

b. Compressive stress

c. Shear stress

d. Impact stress

26 / 60

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

a. Water sorption

b. Polymerization shrinkage

c. Thermal expansion

d. Modulus of elasticity

27 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Polyether

b. Condensation silicones

c. Addition silicones

d. Polysulfides

28 / 60

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

a. Properties of amalgam

b. Have little dimensional change

c. Expand greatly to provide marginal seal against the tooth

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

29 / 60

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

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

b. The tray does not distort during impression making

c. More pressure can be applied during impression making

d. It can hold more amount of impression material

30 / 60

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

a. Metal

b. Amalgam

c. Composite resin

d. Gold alloy

31 / 60

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

a. Type III

b. Type IV

c. Type I

d. Type II

32 / 60

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

a. Barium glass

b. Colloidal silica

c. Lithium aluminum silicate

d. Quartz

33 / 60

Silver has all the following characteristics except 😕

a. Silver in pure form is not used in dental restorations

b. Whitens when added to alloys

c. Silver points serve as a root canal filling material

d. Addition of palladium to silver increases corrosion

34 / 60

In an alloy oxygen scavenger is 😕

a. Palladium

b. Copper

c. Zinc

d. Silver

35 / 60

Minimum light exposure time for composite resins should be 😕

a. 40 sec

b. 20 sec

c. 10 sec

d. 5 sec

36 / 60

KHN of enamel is 😕

a. 300

b. 90-100

c. 600

d. 100

37 / 60

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

a. Base plate wax

b. Utility wax

c. Sticky wax

d. Carding wax

38 / 60

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

a. Creep irregular low-copper

b. 1-hour compressive strength spherical high-copper

c. Creep irregular high-copper

d. Tensile strength spherical high-copper

39 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Wash impression for edentulous patients

b. Dual impression for Partially edentulous patients

c. As interocclusal record material

d. Surgical paste

40 / 60

For luting purpose, the film thickness should be 😕

a. ideally 100 μm

b. 25 μm or less

c. minimum 50 μm

d. up to 75 μm

41 / 60

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

a. Sulphide

b. Oxide

c. Gamma II Phase

d. Gamma I Phase

42 / 60

The main function of zinc in amalgam is 😕

a. To increase the shelf-life of an amalgam

b. To prevent the creep

c. To produce delayed expansion

d. To increase the longevity of amalgam after setting

43 / 60

Which of these statements apply to the filler particles of composites ?

a. Microfilled composites contain more filler than all-purpose composites.

b. All are correct

c. Microfilled

d. Microhybrid composites contain as much as 84% filler by weight.

44 / 60

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

a. Toughness

b. Impact strength

c. Resilience

d. Flexibility

45 / 60

Thermal conductivity is proportional to 😕

a. Fusion temperature

b. Hardness of metal

c. Type of metal

d. Area of conduction

46 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. After metal is tempered

b. Several times in air

c. Under compression

d. Under low temperature

47 / 60

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

a. Brittleness

b. Springiness

c. Hardness

d. Toughness

48 / 60

Acrylic resins are used in which of the following ?

a. Posterior inlays

b. Denture bases

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

d. Anterior onlays

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

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

d. An undertriturated mass is crumbly and dull.

50 / 60

Bis-GMA is a reaction product of 😕

a. Urethane dimethacrylate and glycidyl

b. Bis-phenol-A and methyl methacrylate

c. Bis-phenol-A and urethane dimethacrylate

d. Bis-phenol-A and glycidyl methacrylate

51 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, tin, palladium and zinc

b. Silver, mercury, copper and mercury

c. Silver, tin, copper and zinc

d. Silver, mercury, copper and zinc

52 / 60

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

a. Polyether

b. Polyvinyl siloxane

c. Condensation silicone

d. Polysulfied

53 / 60

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

a. Toughness, rigidity, resilience

b. Elastic limit, yield strength, proportional limit

c. Elastic limit, modulus of elasticity, tensile strength

d. Yield strength, tensile strength, toughness

54 / 60

The following statements about dental porcelains are true except 😕

a. Undergoes firing shrinkage

b. It is brittle in nature

c. Undergoes discoloration

d. Crystalline nature

55 / 60

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

a. Hydrolyzes the water if contaminated

b. Decreases the setting time

c. Decreases ductility

d. Produces contraction

56 / 60

Which of the following composites give rough surfaced finish ?

a. Conventional composites

b. Small particle filled composites

c. Hybrid composites

d. Microfilled composites

57 / 60

Cavity varnish should not be applied when the following is used as a filling material 😕

a. Zinc phosphate

b. Silicate

c. Direct resin-filling material

d. Amalgam

58 / 60

A potentially toxic element in base metal alloys is 😕

a. Molybdenum

b. Magnesium

c. Boron

d. Beryllium

59 / 60

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

a. Requires more mercury for trituration

b. Requires higher forces of condensation

c. Requires less amalgamation time

d. Have longer setting time

60 / 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.

Your score is

The average score is 85%

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