Biomaterial Test

5 votes, 5 avg

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Biomaterial Test

1 / 60

Clinical significance of smear layer :

a. Increases the bonding action of the bonding agent

b. Improve the strength of the composite

c. Bonded to tooth structure and prevents composite adhesion

d. Provides calcium for adhesion of composites

2 / 60

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

a. Organic acid-peroxide

b. Peroxide-amine

c. Organic acid-metal ion

d. Diketone-amine

3 / 60

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

a. Condensation silicones

b. Addition silicones

c. Polysulfides

d. Polyethers

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

c. An undertriturated mass is crumbly and dull.

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

5 / 60

A glaze is placed over the finished composite restoration to 😕

a. No provide a better peripheral seal

b. To reduce surface porosities

c. To change the shade

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

6 / 60

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

a. Glass ionomer

b. Ceramic

c. Gold

d. Waxe

7 / 60

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

a. Depends on rate of mixing

b. Does not alter setting time

c. Decreases setting time

d. Increases setting time

8 / 60

Strength of dental porcelain is dependent on 😕

a. Resistance to fusion

b. Composition

c. No internal structure

d. Rough

9 / 60

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

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

b. They are attached to natural teeth with cements,

c. Artificial acrylic teeth are attached

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

10 / 60

The main ingredient of casting waxes is 😕

a. Paraffin wax

b. Candellila wax

c. Carnauba wax

d. Gum dammar

11 / 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

12 / 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. Esthetics

c. High strength

d. Amalgam

13 / 60

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

a. Polymerization shrinkage

b. Water sorption

c. Modulus of elasticity

d. Thermal expansion

14 / 60

The function of gum dammar in inlay wax is 😕

a. No resistance to carving

b. No smoothness of pattern

c. Less strength to wax

d. To improve smoothness of pattern

15 / 60

Most commonly used pit and fissure sealant is 😕

a. Bis-GMA resin

b. Unfilled acrylic

c. Polyurethane

d. Filled acrylic

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

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

17 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It is harder and has less flow

b. It provides luster to the pattern

c. It is sticky

d. It has low melting temperature

18 / 60

Biting force in the molar region ranges from 😕

a. 1000-1300 N

b. 400-890 N

c. 900-1000 N

d. 600-1000 N

19 / 60

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

a. Hight ductility of metal

b. High malleafility of metal

c. Chemico-mechenical bonding

d. Chemical bonding

20 / 60

The cracks formed on the ceramic during cooling because 😕

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

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

c. The outer layer cools more rapidly than the interior

d. Due to external forces

21 / 60

Following are the functions of impression compound except 😕

a. To record mucostatic impressions

b. To make impression of edentulous ridge

c. To make individual die impression with copper band

d. To make special tray for final impression

22 / 60

Impression compound is characterized by 😕

a. Amorphous in nature with high thermal conductivity

b. Amorphous in nature with low thermal conductivity

c. Crystalline in nature with definite melting point

d. Crystalline in nature with high thermal conductivity

23 / 60

Which one of the following is not true about high-copper dental amalgam restorations ?

a. Contain both Sn and Ag in the composition as well

b. Restorations are more brittle than low-copper versions

c. Produce excessive creep

d. Better corrosion resistance than low-copper dental amalgams

24 / 60

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

a. Porcelain

b. Composite resin

c. Gold alloy

d. Amalgam

25 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Deflasking

b. Packing

c. Curing

d. Polishing

26 / 60

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

a. Reactors

b. Accelerators

c. Retarders

d. Fillers

27 / 60

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

a. Shear stress

b. Tensile stress

c. Impact stress

d. Compressive stress

28 / 60

Porcelain-bonded to metal is stronger when fired 😕

a. Several times in air

b. Under compression

c. Under low temperature

d. After metal is tempered

29 / 60

Resistance of a liquid to motion is called 😕

a. Springiness

b. Viscosity

c. Diffusion

d. Creep

30 / 60

The main function of zinc in amalgam is 😕

a. To produce delayed expansion

b. To increase the shelf-life of an amalgam

c. To increase the longevity of amalgam after setting

d. To prevent the creep

31 / 60

The main resin constituent of polishable composite resin is 😕

a. Cyanoacrylate

b. Polymethyl methacrylate

c. Polycaronate

d. Urethane dimethacrylate

32 / 60

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

a. Addition silicone

b. Polysulfide

c. Polyether

d. Condensation silicone

33 / 60

Proportional limit is defined as :

a. The maximum stress that can be induced without permanent deformation

b. The stress/strain ratio within the elastic limit in a structure

c. A deformation resulting from an applied load

d. The maximum force required to cause a structure to break

34 / 60

Which of the following statements about compomers are true ?

a. Because of their resin content, they require a bonding agent for adhesion to tooth structure.

b. They also are know as GIC

c. They typically are recommended for class II restorations.

d. They are two-paste systems that self-cure within 2 to 3 minutes.

35 / 60

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

a. Stiffness of the material

b. Lowest strain in compression

c. Increased strain rate on unset material

d. Shrinkage of material

36 / 60

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

a. Feldspar

b. Kaolin

c. Potash

d. Silica

37 / 60

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

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

b. All are correct

c. Microfilled

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

38 / 60

Which of the following statements apply to the packable composites ?

a. Their depth of cure allows bulk polymerization, which has been shown to be clinically effective.

b. Their wear rate is low (3.5 μm/year). Which is similar to that of amalgam.

c. Radiopaque

d. They are radiolucent.

39 / 60

Nickel sensitivity in the general population is 😕

a. 1% in the overall population

b. 3% for women

c. 11% for women

d. 3% for men

40 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 37-450C

b. 45-600C

c. Far below the oral temperature

d. 100C higher than mouth temperature

41 / 60

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

a. Triturating precapsulated alloy and mercury

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

c. Mixing in a mortar and pestle

d. A cover over the mixing arms on a triturator

42 / 60

KHN of enamel is 😕

a. 100

b. 300

c. 600

d. 90-100

43 / 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

44 / 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

45 / 60

Polyether is different from other elastomers in the following aspects 😕

a. High stiffiness

b. Can not be used as light cure material

c. Low stiffness

d. Hydropholic in nature

46 / 60

Setting of plaster of Paris is a result of 😕

a. Solubility difference between hemihydrates and dehydrate

b. Loss of water from hemihydrates

c. Interaction between hemihydrates and water

d. Indirect interaction between hemihydrates

47 / 60

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

a. Low alkalinity

b. No Protein lysing effect

c. No antibacterial action

d. High alkalinity

48 / 60

Minimum light exposure time for composite resins should be 😕

a. 20 sec

b. 5 sec

c. 10 sec

d. 40 sec

49 / 60

Working time of denture resin should be at least 😕

a. 15 minutes

b. 5 minutes

c. 10 minutes

d. 20 minutes

50 / 60

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

a. Has an obtudant effect on the pulp

b. The least irritant to the pulp

c. Is the oldest luting agent

d. Is used as a permanent restorative material in adults

51 / 60

In UV curing system the activator employed is 😕

a. Benzoin methyl ether

b. Hydroquinone

c. Methyl methacrylate

d. Dibutyl phthalate

52 / 60

Thickness of the gel between the tray and tissue for either agar or alginate should always be at least 😕

a. 2 mm

b. 4 mm

c. 1 mm

d. 3 mm

53 / 60

The byproduct in condensation silicones is 😕

a. Ethyl alcohol

b. Butyl alcohol

c. Propyl alcohol

d. Methyl alcohol

54 / 60

Thermal conductivity is proportional to 😕

a. Area of conduction

b. Hardness of metal

c. Fusion temperature

d. Type of metal

55 / 60

Of the four types of gold casting alloys, the most commonly used for crowns and bridges is 😕

a. Type II

b. Type I

c. Type III

d. Type IV

56 / 60

Strain that occurs when the material is stressed to its proportional limit is called 😕

a. Resilience

b. Modulus of elasticity

c. Toughness

d. Flexibility

57 / 60

The main use of zinc oxide eugenol cement is 😕

a. Indirect pulp capping agent

b. Temporary restoration

c. Base

d. Permanent restoration

58 / 60

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

a. Toughness

b. Springiness

c. Hardness

d. Brittleness

59 / 60

The catalyst used for condensation silicones is 😕

a. Platinum

b. Lead dioxide

c. Oleic acid

d. Stannous octoate

60 / 60

Alginate impression material deteriorates rapidly at 😕

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

b. Low temperature

c. Elevated temperature

d. Normal room temperature

Your score is

The average score is 42%

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