Biomaterial Test

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Biomaterial Test

1 / 60

Setting time of alginate can be better controlled by 😕

a. Chemical accelerators and retarders

b. Mixing time

c. Changing water: powder ratio

d. Temperature of water used of mixing

2 / 60

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

a. Diamond burs at high speed

b. Carbide burs at high speed

c. Diamond burs at low to medium speed

d. Carbide burs at low to medium speed

3 / 60

The light from the visible light curing unit can cause 😕

a. Retinal damage

b. Corneal ulceration

c. Iritis

d. Cataract

4 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Deflasking

b. Curing

c. Polishing

d. Packing

5 / 60

Which of the following statements is true regarding zinc phosphate cement ?

a. Is the oldest luting agent

b. The least irritant to the pulp

c. Has an obtudant effect on the pulp

d. Is used as a permanent restorative material in adults

6 / 60

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

a. Sn-Hg

b. Ag-Su

c. Cu-Sn

d. Ag-Hg

7 / 60

In alginate impression the final gel is 😕

a. Calcium alginate

b. Sodium alginate

c. Sodium sulphate

d. Calcium sulphate

8 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To reduce gamma II particule

b. Reduce surface microporosities

c. To prevent recurrent carries

d. To reduce discoloration

9 / 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

10 / 60

All are properties of waxes except 😕

a. Plastic deformation

b. Creep

c. Flow

d. Solidification shrinkage

11 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can not lead to cleaned property

b. It can be cleaned properly

c. It can not lead to fungal growth

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

12 / 60

Higher mercury left in an amalgam leads to which of the following ?

a. Higher strength

b. High corrosion

c. Higher creep

d. Low corrosion

13 / 60

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

a. Pulp inflammation

b. Porosity in restoration

c. Secondary caries

d. Sagging of restoration

14 / 60

Porcelain denture teeth 😕

a. Have higher coefficient of thermal expansion than resin teeth

b. Are more resistant of abrasion than gold

c. Are easy to grind and polish

d. Have decreased abrasion resistance than dentin

15 / 60

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

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

b. Triturating precapsulated alloy and mercury

c. A cover over the mixing arms on a triturator

d. Mixing in a mortar and pestle

16 / 60

Thermal conductivity is proportional to 😕

a. Hardness of metal

b. Type of metal

c. Fusion temperature

d. Area of conduction

17 / 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

18 / 60

Hand instruments for composites are made of 😕

a. Teflon-coated metal

b. Stainless steel

c. Titanium

d. Carbon steel

19 / 60

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

a. Amalgam

b. Glass ionomer cement

c. Silicate cement

d. Unfilled

20 / 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. Not indicated

d. Cured for longer period

21 / 60

Calcium hydroxide is used for 😕

a. To prevent recurrent caries

b. Reduce maginal leakage

c. Reinforce the restoration

d. Pulp capping

22 / 60

Oxalates, carbonates, potassium, trisodium phosphates are added to alginate as 😕

a. Fillers

b. Reactors

c. Accelerators

d. Retarders

23 / 60

The greatest amount of dimensional change after setting is exhibited by 😕

a. Condensation silicones

b. Polysulfides

c. Addition silicones

d. Polyethers

24 / 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

25 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Zinc phosphate

b. Zinc silicophoshpate

c. Polycardoxylate

d. Calcum hydroxide

26 / 60

Porosity in denture base resins can be due to 😕

a. Applying sufficient pressure during polymerization

b. Excess heating of resin above its boiling point

c. Adequate mixing of liquid and powder components

d. Well flasking of wax pattern

27 / 60

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

a. Polysulfied

b. Polyvinyl siloxane

c. Polyether

d. Condensation silicone

28 / 60

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

a. Shrinkage of material

b. Increased strain rate on unset material

c. Lowest strain in compression

d. Stiffness of the material

29 / 60

The byproduct in condensation silicones is 😕

a. Ethyl alcohol

b. Propyl alcohol

c. Butyl alcohol

d. Methyl alcohol

30 / 60

Silver has all the following characteristics except 😕

a. Silver points serve as a root canal filling material

b. Whitens when added to alloys

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

d. Addition of palladium to silver increases corrosion

31 / 60

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

a. 1:3

b. 2:1

c. 3:1

d. 1:2

32 / 60

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

a. Subperiosteal

b. Intramucosal frames

c. Endosseus implants

d. Transosteal frames

33 / 60

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

a. Glass ionomer

b. Ceramic

c. Gold

d. Waxe

34 / 60

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

a. Ag-Hg

b. Cu-Sn

c. Sn-Hg

d. Ag-Sn

35 / 60

Nickel in base metal alloys increase its 😕

a. Hardness and fusion temperature

b. Strength

c. Modulus of elasticity

d. S Ductility

36 / 60

Most commonly used pit and fissure sealant is 😕

a. Polyurethane

b. Unfilled acrylic

c. Filled acrylic

d. Bis-GMA resin

37 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 45-600C

b. 37-450C

c. Far below the oral temperature

d. 100C higher than mouth temperature

38 / 60

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

a. Silica

b. Kaolin

c. Potash

d. Feldspar

39 / 60

Elgiloy arch wire is 😕

a. Optical fiber arch wire

b. Cobalt-chromium-nickel alloy

c. β-titanium arch wire

d. Gold alloy

40 / 60

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

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

b. Poly (methyl methacrylate)

c. Polystyrene

d. Pheyl methacrylate

41 / 60

Which of the following initiator-accelerator systems is needed for a light-activated composite?

a. Organic acid-metal ion

b. Diketone-amine

c. Organic acid-peroxide

d. Peroxide-amine

42 / 60

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

a. Amalgam

b. Esthetics

c. Ease of casting

d. High strength

43 / 60

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

a. Direct resin-filling material

b. Zinc phosphate

c. Silicate

d. Amalgam

44 / 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 be shrink as a result of syneresis

c. Is an irreversible hydrocolloid impression material

d. Will take up water and expand if kept wet

45 / 60

Modifiers are added to plaster of Paris mainly to 😕

a. Regulate the setting time

b. Get a smooth surface

c. Reduce porosity

d. Increase strength

46 / 60

A glaze is placed over the finished composite restoration to 😕

a. Create a rough surface that is less receptive to extrinsic stain and plaque retention

b. No provide a better peripheral seal

c. To reduce surface porosities

d. To change the shade

47 / 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

48 / 60

Impression compound is characterized by 😕

a. Amorphous in nature with high thermal conductivity

b. Crystalline in nature with high thermal conductivity

c. Crystalline in nature with definite melting point

d. Amorphous in nature with low thermal conductivity

49 / 60

Which of the following composite is recommended for non stress bearing anterior restoration ?

a. Microfilled composites

b. Hybrid composites

c. Conventional composites

d. Small particles

50 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Ferric oxide

b. Chromium oxide

c. Cobalt oxide

d. Chromium carbide

51 / 60

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

a. Amalgam scrap stored in a closed container

b. Baseboard heating

c. fluorite release

d. Floor carpeting

52 / 60

The noble or base metal alloys used for PFM should have the following requisite :

a. Should be brittle

b. Should bond with dental porcelain

c. Its melting temperature should be low in comparison with firing temperature of porcelain

d. Coefficient of thermal expansion should not be compatible with porcelain

53 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Remove smear layer

b. Facilitate mechanical bonding

c. Provide more strenght

d. Create tags

54 / 60

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

a. Chemico-mechenical bonding

b. Hight ductility of metal

c. Chemical bonding

d. High malleafility of metal

55 / 60

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

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

b. Is combined primarily with silver

c. Composite restorative resins

d. Has the toxic properties of unreacted mercury

56 / 60

Which of the following is called periphery wax ?

a. Bite registration wax

b. Utility wax

c. Sticky wax

d. Beading wax

57 / 60

Glass ionomer cenment is not recommended for 😕

a. Class III restoration

b. Class V restoration

c. Class I restoration

d. Class IV resoration

58 / 60

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

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

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

c. Light from an argon laser will activate polymerization.

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

59 / 60

Amalgam is less prone to corrosion 😕

a. If devoid of the gamma 2 phase

b. If it contains 25-27% of tin

c. If it contains zinc

d. If it contains 4-6% of copper

60 / 60

Commonly used coloring agent in impression plaster is 😕

a. Indigo dye

b. Metallic oxide

c. Congo red

d. Alizarin red

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