Biomaterial Test

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Biomaterial Test

1 / 60

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

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

b. Subsequent oxidation of the tertiary amine

c. Increased solubility of the resin

d. Decreased polymerization of the resin

2 / 60

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

a. Gold alloys

b. Amalgam

c. Ceramic

d. Composite resin

3 / 60

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

a. They are attached to natural teeth with cements,

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

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

d. Artificial acrylic teeth are attached

4 / 60

One of the disadvantages of using quartz as filler in restorative resin is 😕

a. It cause abrasion and wearing of opposing tooth surface

b. It cannot be polished

c. It cannot be reduced to the size of microparticle composite

d. It has low affinity for resin matrix

5 / 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

6 / 60

Crystalline materials have 😕

a. No space lattice

b. Well-defined melting

c. Less stable space lattice

d. No well-defined melting

7 / 60

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

a. Diketone-amine

b. Peroxide-amine

c. Organic acid-metal ion

d. Organic acid-peroxide

8 / 60

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

a. Modulus of elasticity

b. Water sorption

c. Polymerization shrinkage

d. Thermal expansion

9 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Packing

b. Deflasking

c. Polishing

d. Curing

10 / 60

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

a. Fusion temperature

b. Specific temperature

c. Latent heat

d. Temperature of vaporization

11 / 60

Silver has all the following characteristics except 😕

a. Addition of palladium to silver increases corrosion

b. Whitens when added to alloys

c. Silver points serve as a root canal filling material

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

12 / 60

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

a. Silicate cement

b. Glass ionomer cement

c. Amalgam

d. Unfilled

13 / 60

Which of the following is called periphery wax ?

a. Beading wax

b. Bite registration wax

c. Sticky wax

d. Utility wax

14 / 60

Chemically cured resin shrinks:?

a. On the surface only

b. Towards the center of bulk of material

c. Away from the light source

d. On the base only

15 / 60

Setting time of alginate can be better controlled by 😕

a. Changing water: powder ratio

b. Temperature of water used of mixing

c. Chemical accelerators and retarders

d. Mixing time

16 / 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 change the shade

d. To reduce surface porosities

17 / 60

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

a. All of them are polymers

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

c. All of them should be heated before using

d. All of them are a result of secondary reaction

18 / 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

19 / 60

Hand instruments for composites are made of 😕

a. Titanium

b. Stainless steel

c. Carbon steel

d. Teflon-coated metal

20 / 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. Increases setting time

d. Decreases setting time

21 / 60

Proconditioning before GIC restoration is done in order to 😕

a. Remove smear layer

b. Provide more strenght

c. Create tags

d. Facilitate mechanical bonding

22 / 60

In dental plaster the main ingredient is 😕

a. Calcium phosphate

b. Calcium sulfate hemihydarate

c. Calcium sulfate dehydrate

d. Calcium anhydrate

23 / 60

Which of the following properties would be of least importance, when selecting an impression material ?

a. Biocompatibility

b. Adhesion

c. Flow

d. Dimensional stability

24 / 60

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

a. Floor carpeting

b. Amalgam scrap stored in a closed container

c. Baseboard heating

d. Wall carpeting

25 / 60

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

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

b. Pheyl methacrylate

c. Poly (methyl methacrylate)

d. Polystyrene

26 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Camphoroquinone

b. Benzoyl methyl ether

c. Toluidine

d. Bis-phenol-A

27 / 60

All of the following are properties of Co-Cr-Ni wires except 😕

a. Their hardness is comparable to stainless steel

b. They can be heat treated

c. They cannot be soldered or welded

d. They have excellent tarnish and corrosion resistance

28 / 60

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

a. Direct resin-filling material

b. Amalgam

c. Zinc phosphate

d. Silicate

29 / 60

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

a. Polysulfide

b. Condensation silicone

c. Addition silicone

d. Polyether

30 / 60

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

a. Porcelain

b. Gold alloy

c. Composite resin

d. Amalgam

31 / 60

Crystal structures of metals are all the following except 😕

a. Tetragonal

b. Monoclinic

c. Cubic

d. Circular

32 / 60

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

a. It decreases the time for syneresis to occur

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

c. It is the easiest method of removal

d. Faster rate of removal increases the yield strength

33 / 60

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

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

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

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

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

34 / 60

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

a. Polysulfied

b. Polyether

c. Polyvinyl siloxane

d. Condensation silicone

35 / 60

Regarding Knoop hardness number, which of the following material is closest to that of dentine (KHN 65) ?

a. Silicates

b. Pure gold

c. Composites

d. Amalgam

36 / 60

Side effects and complications resulting from treatment by a physician or dentist is 😕

a. Carcinogenesis

b. Biocompatibility

c. Teratogenesis

d. Iatrogenesis

37 / 60

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

a. Small particles

b. Hybrid composites

c. Conventional composites

d. Microfilled composites

38 / 60

Setting of plaster of Paris is a result of 😕

a. Solubility difference between hemihydrates and dehydrate

b. Interaction between hemihydrates and water

c. Indirect interaction between hemihydrates

d. Loss of water from hemihydrates

39 / 60

Gold with high percentage elongation is best for 😕

a. Increase the bond strength

b. To remove metallic oxide

c. To improve the castability

d. To revert sagging during firing

40 / 60

In dental porcelains metallic oxides provide 😕

a. Color but decreases the strength

b. Color and increases the strength

c. Provides refractile property and increases strength

d. Color and provides refractile property

41 / 60

Working time of denture resin should be at least 😕

a. 10 minutes

b. 20 minutes

c. 5 minutes

d. 15 minutes

42 / 60

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

a. 2 mm

b. 1 mm

c. 3 mm

d. 4 mm

43 / 60

The main function of zinc in amalgam is 😕

a. To increase the shelf-life of an amalgam

b. To increase the longevity of amalgam after setting

c. To produce delayed expansion

d. To prevent the creep

44 / 60

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

a. Gold alloy

b. Amalgam

c. Metal

d. Composite resin

45 / 60

The most commonly used implant type presently is 😕

a. Intramucosal implant

b. Transosteal implant

c. Endosseous

d. Subperiosteal

46 / 60

In alginate impression the final gel is 😕

a. Calcium alginate

b. Sodium alginate

c. Sodium sulphate

d. Calcium sulphate

47 / 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

48 / 60

Calcium hydroxide is used for 😕

a. Pulp capping

b. To prevent recurrent caries

c. Reinforce the restoration

d. Reduce maginal leakage

49 / 60

A potentially toxic element in base metal alloys is 😕

a. Boron

b. Magnesium

c. Beryllium

d. Molybdenum

50 / 60

Resistance of a liquid to motion is called 😕

a. Viscosity

b. Springiness

c. Diffusion

d. Creep

51 / 60

Which of the following materials are used for dental implants ?

a. Titanium

b. Cobalt and chromium alloys

c. Metal alloys

d. Gold alloys

52 / 60

The reason zinc oxide eugenol cement is used as a temporary restoration 😕

a. It does not form reparative dentin

b. It has poor tensile strength

c. It does not have anticariogenic activity

d. It has an obtudant effect

53 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Greater bony opposition

b. Lesser bony apposition

c. Presence of fibrous tissue

d. Prolonged healing time

54 / 60

Passiveness of chrome cobalt alloys is due to formation of 😕

a. Chromium carbide

b. Cobalt oxide

c. Chromium oxide

d. Ferric oxide

55 / 60

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

a. Vapor temperature

b. Temperature of specificity

c. Heat temperature

d. Fusion temperature

56 / 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. Ease of casting

c. Esthetics

d. Amalgam

57 / 60

Most commonly used pit and fissure sealant is 😕

a. Polyurethane

b. Bis-GMA resin

c. Unfilled acrylic

d. Filled acrylic

58 / 60

Ideal method firing of porcelain is by using 😕

a. Longer firing at low temperatures

b. Longer firing at high temperatures

c. Shorter firing at low temperatures

d. Shorter firing at higher temperatures

59 / 60

Most common use of Zinc oxide eugenol paste 😕

a. Dual impression for Partially edentulous patients

b. Wash impression for edentulous patients

c. As interocclusal record material

d. Surgical paste

60 / 60

Adhesion in composites is due to 😕

a. Presence of smear layer

b. True chemical bonding to tooth structure

c. Mechanical interlocking

d. Cohesion

Your score is

The average score is 86%

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