Biomaterial Test

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Biomaterial Test

1 / 60

Strength of dental porcelain is dependent on 😕

a. No internal structure

b. Composition

c. Resistance to fusion

d. Rough

2 / 60

One of the following statements which one is incorrect regarding polyether :

a. The main chain of polyether consists of copolymer of ethylene oxide and tetrahydrofuran

b. The main chain consists of copolymer of methylene oxide and tetrahydrofuran

c. The base paste consists of polyether polymer

d. Aromatic sulfonate ester acts as a cross linking agent

3 / 60

Condensation of porcelain is done by all the methods except 😕

a. Vibration method

b. Brush addition technique

c. Ceramming method

d. Spatulation method

4 / 60

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

a. All of them should be heated before using

b. All of them are polymers

c. All of them are a result of secondary reaction

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

5 / 60

In dental plaster the main ingredient is 😕

a. Calcium anhydrate

b. Calcium phosphate

c. Calcium sulfate dehydrate

d. Calcium sulfate hemihydarate

6 / 60

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

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

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

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

d. An undertriturated mass is crumbly and dull.

7 / 60

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

a. High strength

b. Esthetics

c. Ease of casting

d. Amalgam

8 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Nickel

b. Copper

c. Cobalt

d. Silver

9 / 60

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

a. Has a better reaction with zinc oxide

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

c. Reduces burning sensation of paste

d. To increase setting time

10 / 60

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

a. Cu-Sn

b. Sn-Hg

c. Ag-Sn

d. Ag-Hg

11 / 60

Which of the following statements about laboratory composites are true ?

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

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

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

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

12 / 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 definite melting point

d. Crystalline in nature with high thermal conductivity

13 / 60

Calcium hydroxide is used for 😕

a. Reduce maginal leakage

b. Reinforce the restoration

c. Pulp capping

d. To prevent recurrent caries

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 I

d. Type IV

15 / 60

Minimum light exposure time for composite resins should be 😕

a. 5 sec

b. 40 sec

c. 10 sec

d. 20 sec

16 / 60

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

a. Carbone steal

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

c. Artificial waxes teeth are attached

d. They are attached to natural teeth with cements,

17 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Is an irreversible hydrocolloid impression material

b. Will be shrink as a result of syneresis

c. Will take up water and expand if kept wet

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

18 / 60

Silver has all the following characteristics except 😕

a. Addition of palladium to silver increases corrosion

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

c. Silver points serve as a root canal filling material

d. Whitens when added to alloys

19 / 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

20 / 60

Adhesion in composites is due to 😕

a. Presence of smear layer

b. True chemical bonding to tooth structure

c. Cohesion

d. Mechanical interlocking

21 / 60

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

a. Decreased polymerization of the resin

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

c. Subsequent oxidation of the tertiary amine

d. Increased solubility of the resin

22 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It provides luster to the pattern

b. It is sticky

c. It is harder and has less flow

d. It has low melting temperature

23 / 60

Metal has the following properties except 😕

a. Pure metals are not useful in dentistry

b. Electroplated silver and copper are used in dies

c. Metal is any element that ionizes positively in solution

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

24 / 60

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

a. Condensation silicone

b. Polyether

c. Polysulfide

d. Addition silicone

25 / 60

Crystalline materials have 😕

a. Well-defined melting

b. No well-defined melting

c. No space lattice

d. Less stable space lattice

26 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can not lead to fungal growth

b. It can not lead to cleaned property

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

d. It can be cleaned properly

27 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Cobalt oxide

b. Ferric oxide

c. Chromium oxide

d. Chromium carbide

28 / 60

Alginate impression material deteriorates rapidly at 😕

a. Normal room temperature

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

c. Low temperature

d. Elevated temperature

29 / 60

All are properties of waxes except 😕

a. Solidification shrinkage

b. Plastic deformation

c. Creep

d. Flow

30 / 60

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

a. Hight ductility of metal

b. Chemical bonding

c. High malleafility of metal

d. Chemico-mechenical bonding

31 / 60

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

a. Increases setting time

b. Decreases setting time

c. Does not alter setting time

d. Depends on rate of mixing

32 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Curing

b. Packing

c. Deflasking

d. Polishing

33 / 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. 30 mg Hg/m3 of air

d. 100 mg Hg/m3 of air

34 / 60

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

a. No Protein lysing effect

b. No antibacterial action

c. Low alkalinity

d. High alkalinity

35 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 45-600C

b. 100C higher than mouth temperature

c. Far below the oral temperature

d. 37-450C

36 / 60

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

a. Requires higher forces of condensation

b. Requires less amalgamation time

c. Requires more mercury for trituration

d. Have longer setting time

37 / 60

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

a. Polyether

b. Polysulfides

c. Addition silicones

d. Condensation silicones

38 / 60

Which of the following phases in dental amalgam restoration is most prone to electrochemical properties ?

a. Cu-Sn

b. Sn-Hg

c. Ag-Hg

d. Ag-Sn

39 / 60

Thermal conductivity is proportional to 😕

a. Hardness of metal

b. Type of metal

c. Fusion temperature

d. Area of conduction

40 / 60

Clinical significance of smear layer :

a. Increases the bonding action of the bonding agent

b. Bonded to tooth structure and prevents composite adhesion

c. Improve the strength of the composite

d. Provides calcium for adhesion of composites

41 / 60

Commonly used viscosity controller in composites is 😕

a. Bis-GAM

b. Polyurethanes

c. Methyl methacrylate

d. TEG-DMA

42 / 60

The tendency of stainless steel to break under repeated condition of cyclic stressing below the ultimate strength is 😕

a. Resilience

b. Creep

c. Fatigue

d. Ductility

43 / 60

Which of the following statements about adhesion of composite restorations to tooth structure are true ?

a. Most bonding agent bond more effectively to a dry tooth surface.

b. The bonding agent forms a hybrid layer with enamel.

c. Bonding is achieved to enamel by application of an acid etchant followed by application of a bonding agent and then the composites resin.

d. The bonding agent forms a micromechanical bond with enamel but a chemical bond with dentin.

44 / 60

In alginate impression the final gel is 😕

a. Calcium alginate

b. Sodium sulphate

c. Calcium sulphate

d. Sodium alginate

45 / 60

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

a. Specific temperature

b. Fusion temperature

c. Latent heat

d. Temperature of vaporization

46 / 60

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

a. Condensation silicone

b. Polyether

c. Polysulfied

d. Polyvinyl siloxane

47 / 60

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

a. Has the toxic properties of unreacted mercury

b. Is combined primarily with silver

c. Composite restorative resins

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

48 / 60

The byproduct in condensation silicones is 😕

a. Methyl alcohol

b. Ethyl alcohol

c. Propyl alcohol

d. Butyl alcohol

49 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. Condense the unattacked gamma I particles

b. To reduce gamma II particules

c. Condense the unattacked gamma II particles

d. Condense the unattacked gamma particles

50 / 60

KHN of enamel is 😕

a. 90-100

b. 600

c. 300

d. 100

51 / 60

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

a. Carbide burs at low to medium speed

b. Diamond burs at high speed

c. Diamond burs at low to medium speed

d. Carbide burs at high speed

52 / 60

Most common use of Zinc oxide eugenol paste 😕

a. As interocclusal record material

b. Dual impression for Partially edentulous patients

c. Wash impression for edentulous patients

d. Surgical paste

53 / 60

The main resin constituent of polishable composite resin is 😕

a. Cyanoacrylate

b. Urethane dimethacrylate

c. Polycaronate

d. Polymethyl methacrylate

54 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It is low in strength

b. Pure zinc has no application in dentistry

c. It is relatively soft and ductile

d. It does not oxidize

55 / 60

A portion of a posterior tooth that is subject to high biting forces would likely be restored with which of the following ?

a. Acrylic resin

b. Composite resin

c. Glass ionomer

d. Amalgam

56 / 60

Which of the following is the best choice of restorative material to achieve moderate to high strength, fluorite release, and esthetics ?

a. Composite

b. Glass ionomer

c. Hybrid ionomer

d. Compomer

57 / 60

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

a. Polymerization shrinkage

b. Water sorption

c. Thermal expansion

d. Modulus of elasticity

58 / 60

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

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

b. They are attached to natural teeth with cements,

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

d. Artificial acrylic teeth are attached

59 / 60

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

a. Shrinkage of material

b. Stiffness of the material

c. Increased strain rate on unset material

d. Lowest strain in compression

60 / 60

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

a. Produces contraction

b. Decreases the setting time

c. Decreases ductility

d. Hydrolyzes the water if contaminated

Your score is

The average score is 85%

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