Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

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

a. Chemical bonding

b. Hight ductility of metal

c. High malleafility of metal

d. Chemico-mechenical bonding

2 / 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. Pheyl methacrylate

d. Poly (methyl methacrylate)

3 / 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. Thermal insulation

c. Esthetics

d. High strength

4 / 60

Impression compound is characterized by 😕

a. Amorphous in nature with low thermal conductivity

b. Amorphous in nature with high thermal conductivity

c. Crystalline in nature with high thermal conductivity

d. Crystalline in nature with definite melting point

5 / 60

Softening of impressing compound is best accomplished by 😕

a. Open flame

b. Oil bath

c. Water bath

d. Dry heat

6 / 60

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

a. Beading wax

b. Boxing wax

c. Carding wax

d. Utility wax

7 / 60

Elgiloy arch wire is 😕

a. Optical fiber arch wire

b. β-titanium arch wire

c. Gold alloy

d. Cobalt-chromium-nickel alloy

8 / 60

Most common use of Zinc oxide eugenol paste 😕

a. As interocclusal record material

b. Wash impression for edentulous patients

c. Dual impression for Partially edentulous patients

d. Surgical paste

9 / 60

The following statements about dental porcelains are true except 😕

a. Undergoes discoloration

b. Undergoes firing shrinkage

c. Crystalline nature

d. It is brittle in nature

10 / 60

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

a. They are attached to upper natural teeth with cements,

b. Artificial acrylic teeth are attached

c. They are attached to lower natural teeth with cements,

d. They are attached to natural teeth with cements,

11 / 60

Inorganic phase in a composite matrix 😕

a. Decreases the mechanical strength

b. Increases the polymerization shrinkage

c. Increases the mechanical strength

d. Increases coefficient of thermal expansion

12 / 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. 0.04 mg Hg/m3 of air

b. 0.05 mg Hg/m3 of air

c. 100 mg Hg/m3 of air

d. 30 mg Hg/m3 of air

13 / 60

Setting of plaster of Paris is a result of 😕

a. Solubility difference between hemihydrates and dehydrate

b. Indirect interaction between hemihydrates

c. Loss of water from hemihydrates

d. Interaction between hemihydrates and water

14 / 60

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

a. Requires higher forces of condensation

b. Requires more mercury for trituration

c. Requires less amalgamation time

d. Have longer setting time

15 / 60

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

a. Condensation silicone

b. Addition silicone

c. Polysulfide

d. Polyether

16 / 60

Biting force in the molar region ranges from 😕

a. 600-1000 N

b. 900-1000 N

c. 400-890 N

d. 1000-1300 N

17 / 60

In a porcelain fused to metal restoration, when the coefficient of thermal expansion of metal and porcelain are different 😕

a. Porcelain will not bond with metal

b. Porcelain will provide good shade

c. Porcelain will wear off

d. Porcelain will crack on cooling

18 / 60

In UV curing system the activator employed is 😕

a. Hydroquinone

b. Methyl methacrylate

c. Dibutyl phthalate

d. Benzoin methyl ether

19 / 60

The temperature at which a solid changes to liquid is known as its 😕

a. Heat temperature

b. Vapor temperature

c. Temperature of specificity

d. Fusion temperature

20 / 60

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

a. Impact stress

b. Shear stress

c. Tensile stress

d. Compressive stress

21 / 60

Regarding Knoop hardness number, which of the following material is closest to that of dentine (KHN 65) ?

a. Amalgam

b. Composites

c. Pure gold

d. Silicates

22 / 60

Porcelain denture teeth 😕

a. Are more resistant of abrasion than gold

b. Have higher coefficient of thermal expansion than resin teeth

c. Are easy to grind and polish

d. Have decreased abrasion resistance than dentin

23 / 60

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

a. All are correct

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

c. Microfilled

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

24 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can not lead to fungal growth

b. It can be cleaned properly

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

d. It can not lead to cleaned property

25 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Regulate the setting time

b. Increase strength

c. Reduce porosity

d. Get a smooth surface

26 / 60

All are properties of waxes except 😕

a. Plastic deformation

b. Flow

c. Creep

d. Solidification shrinkage

27 / 60

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

a. Have little dimensional change

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

c. Properties of amalgam

d. Expand greatly to provide marginal seal against the tooth

28 / 60

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

a. Percentage elongation

b. Flexibility

c. Proportional limit

d. Yield strength

29 / 60

Which of the following statements about curing of composites are true ?

a. Exposure times of 2 to 3 seconds are needed for polymerization with visible light.

b. Before light activation, the base and catalyst pastes are mixed.

c. Lights with both blue and red wavelengths are equally effective for polymerization.

d. Light from an argon laser will activate polymerization.

30 / 60

A full crown on a maxillary anterior tooth may be restored with which of the following restorative materials ?

a. Composite resin

b. Gold alloys

c. Ceramic

d. Amalgam

31 / 60

Bis-GMA is a reaction product of 😕

a. Urethane dimethacrylate and glycidyl

b. Bis-phenol-A and urethane dimethacrylate

c. Bis-phenol-A and methyl methacrylate

d. Bis-phenol-A and glycidyl methacrylate

32 / 60

The function of gum dammar in inlay wax is 😕

a. No smoothness of pattern

b. To improve smoothness of pattern

c. No resistance to carving

d. Less strength to wax

33 / 60

All of the following are properties of Co-Cr-Ni wires except 😕

a. Their hardness is comparable to stainless steel

b. They can be heat treated

c. They cannot be soldered or welded

d. They have excellent tarnish and corrosion resistance

34 / 60

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

a. Space lattice

b. Strain

c. Amorphous material

d. Stress

35 / 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 IV

d. Type II

36 / 60

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

a. Artificial waxes teeth are attached

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

c. Carbone steal

d. They are attached to natural teeth with cements,

37 / 60

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

a. Brittleness

b. Toughness

c. Springiness

d. Hardness

38 / 60

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

a. 0.05 mg Hg/m3 of air

b. 100 ng Hg/m3 of air

c. 30 ng Hg/m3 of air

d. All are corrects

39 / 60

Working time of denture resin should be at least 😕

a. 20 minutes

b. 5 minutes

c. 15 minutes

d. 10 minutes

40 / 60

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

a. Temperature of vaporization

b. Latent heat

c. Specific temperature

d. Fusion temperature

41 / 60

Which of the following elastomers is suited for multiple cast pouring 😕

a. Polyether

b. Polysulfide

c. Addition silicone

d. Condensation silicone

42 / 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

43 / 60

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

a. Cu-Sn

b. Sn-Hg

c. Ag-Su

d. Ag-Hg

44 / 60

The main ingredient of casting waxes is 😕

a. Carnauba wax

b. Gum dammar

c. Candellila wax

d. Paraffin wax

45 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Chromium oxide

b. Chromium carbide

c. Ferric oxide

d. Cobalt oxide

46 / 60

Which of the following composites give rough surfaced finish ?

a. Small particle filled composites

b. Hybrid composites

c. Microfilled composites

d. Conventional composites

47 / 60

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

a. All of them are a result of secondary reaction

b. All of them should be heated before using

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

d. All of them are polymers

48 / 60

Condensation of porcelain is done by all the methods except 😕

a. Spatulation method

b. Brush addition technique

c. Vibration method

d. Ceramming method

49 / 60

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

a. Glass ionomer cement

b. Unfilled

c. Silicate cement

d. Amalgam

50 / 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

51 / 60

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

a. Dimensional stability

b. Adhesion

c. Flow

d. Biocompatibility

52 / 60

Porosity in denture base resins can be due to 😕

a. Excess heating of resin above its boiling point

b. Well flasking of wax pattern

c. Adequate mixing of liquid and powder components

d. Applying sufficient pressure during polymerization

53 / 60

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

a. Ease of casting

b. Amalgam

c. Esthetics

d. High strength

54 / 60

Which of the following is called periphery wax ?

a. Bite registration wax

b. Utility wax

c. Sticky wax

d. Beading wax

55 / 60

Setting time of alginate can be better controlled by 😕

a. Chemical accelerators and retarders

b. Temperature of water used of mixing

c. Mixing time

d. Changing water: powder ratio

56 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Deflasking

b. Packing

c. Polishing

d. Curing

57 / 60

Impression plaster is a 😕

a. Reversible impression material

b. Mucocompressive material

c. Mucostatic material

d. Thermoplastic material

58 / 60

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

a. Porosity in restoration

b. Sagging of restoration

c. Secondary caries

d. Pulp inflammation

59 / 60

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

a. A cover over the mixing arms on a triturator

b. Triturating precapsulated alloy and mercury

c. Mixing in a mortar and pestle

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

60 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Silver

b. Copper

c. Cobalt

d. Nickel

Your score is

The average score is 42%

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