Biomaterial Test

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Biomaterial Test

1 / 60

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

a. Utility wax

b. Carding wax

c. Sticky wax

d. Base plate wax

2 / 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 can be employed as anterior filling materials

c. All of them are a result of secondary reaction

d. All of them are polymers

3 / 60

When a mechanical device is used for mixing addition silicones 😕

a. There is no greater uniformity in proportioning and mixing

b. Mixing time is long

c. More possibilities of contamination

d. Mixing time is reduced

4 / 60

Which one of the following office conditions minimize the health hazard from spilled mercury ?

a. fluorite release

b. Floor carpeting

c. Baseboard heating

d. Amalgam scrap stored in a closed container

5 / 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. Well flasking of wax pattern

d. Adequate mixing of liquid and powder components

6 / 60

Greening effect of porcelain is due to 😕

a. Platinum

b. Palladium

c. Silver

d. Golde

7 / 60

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

a. Modulus of elasticity

b. Thermal expansion

c. Polymerization shrinkage

d. Water sorption

8 / 60

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

a. Intramucosal frames

b. Transosteal frames

c. Endosseus implants

d. Subperiosteal

9 / 60

Following are the functions of impression compound except 😕

a. To record mucostatic impressions

b. To make special tray for final impression

c. To make impression of edentulous ridge

d. To make individual die impression with copper band

10 / 60

Which of the following components acts as a refractory material in porcelain ?

a. Feldspar

b. Kaolin

c. Potash

d. Silica

11 / 60

One of the following statements which one is incorrect regarding addition silicones 😕

a. Undetectable distortion on removal

b. Can be used in automixing devices

c. Dimensionally stable even after 1 week

d. No evolution of any byproduct under all circumstances

12 / 60

Which of the following statements about laboratory composites are true ?

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

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

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

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

13 / 60

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

a. It decreases the time for syneresis to occur

b. Faster rate of removal increases the yield strength

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

d. It is the easiest method of removal

14 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Bonding between coupling agent and filler

b. Adhesive bonding between matrix and filler

c. Bonding with tooth structure

d. Bonding between coupling agent and tooth structure

15 / 60

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

a. Avoid polishing amalgams

b. Vacuum up a spill immediately

c. Sterilize amalgam scrap

d. Avoid touching freshly mixed amalgam

16 / 60

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

a. Styrene-acrylonitrile

b. Ethyl silicate

c. Polydimethyl siloxane

d. Acrylic resin

17 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Can not be used as light cure material

b. Hydropholic in nature

c. Low stiffness

d. High stiffiness

18 / 60

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

a. Type IV

b. Type III

c. Type I

d. Type II

19 / 60

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

a. Latent heat

b. Temperature of vaporization

c. Specific temperature

d. Fusion temperature

20 / 60

In dental plaster the main ingredient is 😕

a. Calcium sulfate hemihydarate

b. Calcium phosphate

c. Calcium anhydrate

d. Calcium sulfate dehydrate

21 / 60

The cracks formed on the ceramic during cooling because 😕

a. Due to external forces

b. The inner layer cools more rapidly than the outer layer

c. The cooling of the outer and the inner layer occurs at the same rate

d. The outer layer cools more rapidly than the interior

22 / 60

Binder in the phosphate investment is 😕

a. Magnesium oxide and monoammonium phosphate

b. Phosphoric acid

c. Manganese dioxide

d. Cristobalite

23 / 60

Contamination of zinc-containing amalgam by moisture during triturating or condensation :

a. Results in a marked expansion

b. Results in a sharp decrease in flow

c. Increases the setting time

d. Has no appreciable effect on properties except to the susceptibility to tarnish

24 / 60

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

a. Amalgam

b. Gold alloys

c. Composite resin

d. Ceramic

25 / 60

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

a. Composite resin

b. Silicate cement

c. Unfilled acrylic resin

d. Glass ionomer cement

26 / 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 base paste consists of polyether polymer

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

d. Aromatic sulfonate ester acts as a cross linking agent

27 / 60

Softening of impressing compound is best accomplished by 😕

a. Dry heat

b. Water bath

c. Oil bath

d. Open flame

28 / 60

Gypsum investments should not be heated above 😕

a. 7000C

b. 10000C

c. 17000C

d. 4500C

29 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Increases surface smoothness

b. Conserves the material

c. Decreases air voids in the restoration

d. Increases strength and abrasive resistance

30 / 60

Resistance of a liquid to motion is called 😕

a. Diffusion

b. Viscosity

c. Springiness

d. Creep

31 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Camphoroquinone

b. Benzoyl methyl ether

c. Toluidine

d. Bis-phenol-A

32 / 60

Gold with high percentage elongation is best for 😕

a. To remove metallic oxide

b. To revert sagging during firing

c. To improve the castability

d. Increase the bond strength

33 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Addition silicones

b. Polysulfides

c. Polyether

d. Condensation silicones

34 / 60

The desirable quality of porcelain is 😕

a. Requirement of color

b. Thermal expansion

c. Toughness without brittleness

d. Translucency

35 / 60

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

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

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

c. An undertriturated mass is crumbly and dull.

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

36 / 60

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

a. Addition silicone

b. Condensation silicone

c. Polysulfide

d. Polyether

37 / 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. High modulus of resilience

d. Color matching with the tooth structure is excellent

38 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Polyacrylic acid for 10 seconds

b. Polyacrylic acid for 60 seconds

c. Phosphoric acid for 10 seconds

d. Phosphoric acid for 60 seconds

39 / 60

Commonly used coloring agent in impression plaster is 😕

a. Metallic oxide

b. Congo red

c. Indigo dye

d. Alizarin red

40 / 60

Alginate impression material deteriorates rapidly at 😕

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

b. Elevated temperature

c. Normal room temperature

d. Low temperature

41 / 60

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

a. Composite resin

b. Gold alloy

c. Metal

d. Amalgam

42 / 60

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

a. Rockwell hardness test

b. Knoop hardness test

c. Brinell hardness test

d. Vichers hardness test

43 / 60

Chemically cured resin shrinks:?

a. On the surface only

b. Towards the center of bulk of material

c. On the base only

d. Away from the light source

44 / 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

45 / 60

Which of the following is called periphery wax ?

a. Sticky wax

b. Utility wax

c. Bite registration wax

d. Beading wax

46 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. Condense the unattacked gamma I particles

b. Condense the unattacked gamma II particles

c. To reduce gamma II particules

d. Condense the unattacked gamma particles

47 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Curing

b. Deflasking

c. Packing

d. Polishing

48 / 60

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

a. Decreases the setting time

b. Produces contraction

c. Decreases ductility

d. Hydrolyzes the water if contaminated

49 / 60

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

a. Flexibility

b. Yield strength

c. Proportional limit

d. Percentage elongation

50 / 60

Which of the following office conditions minimize the health hazard from spilled mercury ?

a. Baseboard heating

b. Floor carpeting

c. Wall carpeting

d. Amalgam scrap stored in a closed container

51 / 60

Commonly used filler in composite is 😕

a. Quartz

b. Colloidal silica

c. Aluminum

d. Glass

52 / 60

Nickel in base metal alloys increase its 😕

a. Modulus of elasticity

b. Strength

c. S Ductility

d. Hardness and fusion temperature

53 / 60

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

a. High alkalinity

b. No antibacterial action

c. No Protein lysing effect

d. Low alkalinity

54 / 60

Elgiloy arch wire is 😕

a. Cobalt-chromium-nickel alloy

b. Gold alloy

c. Optical fiber arch wire

d. β-titanium arch wire

55 / 60

In dental porcelains metallic oxides provide 😕

a. Color and provides refractile property

b. Color but decreases the strength

c. Color and increases the strength

d. Provides refractile property and increases strength

56 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

a. When the material is glossy

b. Exactly after four minutes after kneading

c. When the material cannot be intended by a blunt instrument

d. When it can be easily indented by a blunt instrument

57 / 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. 30 mg Hg/m3 of air

c. 0.05 mg Hg/m3 of air

d. 100 mg Hg/m3 of air

58 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Increase strength

b. Reduce porosity

c. Get a smooth surface

d. Regulate the setting time

59 / 60

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

a. Sn-Hg

b. Ag-Sn

c. Cu-Sn

d. Ag-Hg

60 / 60

The main resin constituent of polishable composite resin is 😕

a. Polymethyl methacrylate

b. Cyanoacrylate

c. Urethane dimethacrylate

d. Polycaronate

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