Biomaterial Test

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Biomaterial Test

1 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It is harder and has less flow

b. It is sticky

c. It has low melting temperature

d. It provides luster to the pattern

2 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Greater bony opposition

b. Presence of fibrous tissue

c. Lesser bony apposition

d. Prolonged healing time

3 / 60

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

a. Gold alloy

b. Amalgam

c. Ceramic

d. Silver alloys

4 / 60

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

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

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

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

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

5 / 60

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

a. Pulp inflammation

b. Secondary caries

c. Porosity in restoration

d. Sagging of restoration

6 / 60

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

a. Temperature of specificity

b. Vapor temperature

c. Heat temperature

d. Fusion temperature

7 / 60

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

a. Boxing wax

b. Carding wax

c. Beading wax

d. Utility wax

8 / 60

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

a. Baseboard heating

b. Amalgam scrap stored in a closed container

c. Floor carpeting

d. fluorite release

9 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 45-600C

b. 37-450C

c. 100C higher than mouth temperature

d. Far below the oral temperature

10 / 60

When the gold content of gold alloys increases 😕

a. The percentage elongation decrease

b. Ductility decrease

c. The corrosion resistance increases

d. The hardness decrease

11 / 60

Bis-GMA is a reaction product of 😕

a. Bis-phenol-A and methyl methacrylate

b. Bis-phenol-A and glycidyl methacrylate

c. Urethane dimethacrylate and glycidyl

d. Bis-phenol-A and urethane dimethacrylate

12 / 60

Softening of impressing compound is best accomplished by 😕

a. Open flame

b. Dry heat

c. Oil bath

d. Water bath

13 / 60

Commonly used coloring agent in impression plaster is 😕

a. Indigo dye

b. Congo red

c. Metallic oxide

d. Alizarin red

14 / 60

Binder in the phosphate investment is 😕

a. Phosphoric acid

b. Cristobalite

c. Manganese dioxide

d. Magnesium oxide and monoammonium phosphate

15 / 60

Which one 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

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

a. Lithium aluminum silicate

b. Quartz

c. Barium glass

d. Colloidal silica

17 / 60

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

a. Intramucosal frames

b. Subperiosteal

c. Transosteal frames

d. Endosseus implants

18 / 60

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

a. Avoid polishing amalgams

b. Sterilize amalgam scrap

c. Avoid touching freshly mixed amalgam

d. Vacuum up a spill immediately

19 / 60

Porcelain denture teeth 😕

a. Have decreased abrasion resistance than dentin

b. Are more resistant of abrasion than gold

c. Have higher coefficient of thermal expansion than resin teeth

d. Are easy to grind and polish

20 / 60

Thermal conductivity is proportional to 😕

a. Type of metal

b. Hardness of metal

c. Area of conduction

d. Fusion temperature

21 / 60

Working time of denture resin should be at least 😕

a. 10 minutes

b. 20 minutes

c. 15 minutes

d. 5 minutes

22 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

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

b. When the material is glossy

c. Exactly after four minutes after kneading

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

23 / 60

A small portion of an anterior tooth would most likely be restored with which of the following ?

a. Porcelain

b. Amalgam

c. Gold alloy

d. Composite resin

24 / 60

The following statements about dental porcelains are true except 😕

a. It is brittle in nature

b. Undergoes firing shrinkage

c. Undergoes discoloration

d. Crystalline nature

25 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Zinc phosphate

b. Zinc silicophoshpate

c. Polycardoxylate

d. Calcum hydroxide

26 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Silver

b. Cobalt

c. Copper

d. Nickel

27 / 60

A glaze is placed over the finished composite restoration to 😕

a. To change the shade

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

c. To reduce surface porosities

d. No provide a better peripheral seal

28 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, mercury, copper and mercury

b. Silver, tin, palladium and zinc

c. Silver, mercury, copper and zinc

d. Silver, tin, copper and zinc

29 / 60

Full denture bases are usually made from which of the following materials ?

a. Gold alloys

b. Ceramic

c. Composite restorative resins

d. Acrylic resin

30 / 60

Which of the following base is contraindicated for composites ?

a. Zinc oxide eugenol

b. Zinc phosphate

c. Glass ionomer cement

d. Calcium hydroxide

31 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can not lead to fungal growth

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

c. It can not lead to cleaned property

d. It can be cleaned properly

32 / 60

Impression compound is characterized by 😕

a. Crystalline in nature with definite melting point

b. Amorphous in nature with high thermal conductivity

c. Amorphous in nature with low thermal conductivity

d. Crystalline in nature with high thermal conductivity

33 / 60

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

a. Potash

b. Silica

c. Feldspar

d. Kaolin

34 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Curing

b. Deflasking

c. Packing

d. Polishing

35 / 60

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

a. Conventional composites

b. Hybrid composites

c. Microfilled composites

d. Small particles

36 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Cost factor is high

b. Bond between agar and alginate is not very strong

c. Difficult to manipulate

d. Maximum details are not produced

37 / 60

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

a. Diamond burs at low to medium speed

b. Carbide burs at high speed

c. Carbide burs at low to medium speed

d. Diamond burs at high speed

38 / 60

For luting purpose, the film thickness should be 😕

a. up to 75 μm

b. ideally 100 μm

c. 25 μm or less

d. minimum 50 μm

39 / 60

Acrylic resins are used in which of the following ?

a. Denture bases

b. Anterior onlays

c. Posterior inlays

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

40 / 60

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

a. Produces contraction

b. Decreases ductility

c. Decreases the setting time

d. Hydrolyzes the water if contaminated

41 / 60

Silver has all the following characteristics except 😕

a. Whitens when added to alloys

b. Addition of palladium to silver increases corrosion

c. Silver points serve as a root canal filling material

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

42 / 60

All are properties of waxes except 😕

a. Solidification shrinkage

b. Plastic deformation

c. Flow

d. Creep

43 / 60

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

a. Reduce early marginal leakage tooth structure

b. Provide strength of amalgam

c. Provide electrical insulation

d. Provide thermal insulation

44 / 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

45 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Bonding with tooth structure

b. Bonding between coupling agent and filler

c. Bonding between coupling agent and tooth structure

d. Adhesive bonding between matrix and filler

46 / 60

Minimum light exposure time for composite resins should be 😕

a. 40 sec

b. 10 sec

c. 5 sec

d. 20 sec

47 / 60

Calcium hydroxide is used for 😕

a. Reduce maginal leakage

b. To prevent recurrent caries

c. Pulp capping

d. Reinforce the restoration

48 / 60

The chemistry behind the condensation of the amalgam is to 😕

a. Condense the unattacked gamma II particles

b. Condense the unattacked gamma I particles

c. To reduce gamma II particules

d. Condense the unattacked gamma particles

49 / 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

50 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Create tags

b. Provide more strenght

c. Remove smear layer

d. Facilitate mechanical bonding

51 / 60

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

a. Amalgam

b. Ease of casting

c. Esthetics

d. High strength

52 / 60

When a mechanical device is used for mixing addition silicones 😕

a. Mixing time is long

b. There is no greater uniformity in proportioning and mixing

c. Mixing time is reduced

d. More possibilities of contamination

53 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To reduce discoloration

b. To prevent recurrent carries

c. To reduce gamma II particule

d. Reduce surface microporosities

54 / 60

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

a. Organic acid-peroxide

b. Organic acid-metal ion

c. Peroxide-amine

d. Diketone-amine

55 / 60

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

a. Ag-Hg

b. Cu-Sn

c. Ag-Sn

d. Sn-Hg

56 / 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

57 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Vulcanizing

b. Fusing

c. Sintering

d. Fritting

58 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Bis-phenol-A

b. Camphoroquinone

c. Toluidine

d. Benzoyl methyl ether

59 / 60

The primary difference between low- and high-copper amalgams is which of the following ?

a. The amount of copper and zinc

b. The amount of copper and tin

c. The amount of copper and silver

d. The amount of copper

60 / 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. Faster rate of removal increases the yield strength

d. It is the easiest method of removal

Your score is

The average score is 44%

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