Biomaterial Test

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Biomaterial Test

1 / 60

The main use of zinc oxide eugenol cement is 😕

a. Permanent restoration

b. Temporary restoration

c. Indirect pulp capping agent

d. Base

2 / 60

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

a. All of them are a result of secondary reaction

b. All of them should be heated before using

c. All of them are polymers

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

3 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Can not be used as light cure material

b. High stiffiness

c. Hydropholic in nature

d. Low stiffness

4 / 60

The tendency of stainless steel to break under repeated condition of cyclic stressing below the ultimate strength is 😕

a. Creep

b. Resilience

c. Fatigue

d. Ductility

5 / 60

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

a. Fusion temperature

b. Temperature of vaporization

c. Latent heat

d. Specific temperature

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

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

7 / 60

Minimum light exposure time for composite resins should be 😕

a. 5 sec

b. 10 sec

c. 20 sec

d. 40 sec

8 / 60

Wrought metal 😕

a. Cannot be rendered corrosion resistant

b. Can be formed by working on a cast metal

c. Can be formed by pouring molten metal into a mold

d. Cannot be heat treated

9 / 60

Resistance of a liquid to motion is called 😕

a. Creep

b. Springiness

c. Viscosity

d. Diffusion

10 / 60

The light-cured restorative resins have advantages over chemically activated restorative resins as 😕

a. It has not more working time available

b. It is more sensitive to oxygen inhibitors

c. It takes more time for curing

d. It has more working time available

11 / 60

Which of the following occurs when dental amalgam is overmixed ?

a. Compressive strength decreases

b. Corrosion decreases

c. Tensile strength increases

d. Corrosion increases

12 / 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. 0.05 mg Hg/m3 of air

c. 30 mg Hg/m3 of air

d. 100 mg Hg/m3 of air

13 / 60

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

a. It does not have anticariogenic activity

b. It has an obtudant effect

c. It does not form reparative dentin

d. It has poor tensile strength

14 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Lesser bony apposition

b. Greater bony opposition

c. Presence of fibrous tissue

d. Prolonged healing time

15 / 60

When the gold content of gold alloys increases 😕

a. Ductility decrease

b. The percentage elongation decrease

c. The hardness decrease

d. The corrosion resistance increases

16 / 60

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

a. 2:1

b. 3:1

c. 1:2

d. 1:3

17 / 60

Biting force in the molar region ranges from 😕

a. 600-1000 N

b. 900-1000 N

c. 1000-1300 N

d. 400-890 N

18 / 60

Which of the following elastomers is suited for multiple cast pouring 😕

a. Polyether

b. Addition silicone

c. Condensation silicone

d. Polysulfide

19 / 60

Which statements are true for bonding of amalgam to tooth structure ?

a. The most effective bonding agents contain copalite.

b. The use of amalgam bonding reduces marginal leakage of amalgam restorations.

c. The use of amalgam bonding restores the strength of the clinical crown to its original condition.

d. Shear bond strength using amalgam bonding to teeth in clinically proven to be as high as that for bonding composites to teeth.

20 / 60

Property which distinguishes composites from filled acrylic resins 😕

a. Bonding between coupling agent and tooth structure

b. Bonding with tooth structure

c. Adhesive bonding between matrix and filler

d. Bonding between coupling agent and filler

21 / 60

In a porcelain fused to metal restoration, when the coefficient of thermal expansion of metal and porcelain are different 😕

a. Porcelain will crack on cooling

b. Porcelain will wear off

c. Porcelain will provide good shade

d. Porcelain will not bond with metal

22 / 60

Calcium hydroxide is used for 😕

a. To prevent recurrent caries

b. Reduce maginal leakage

c. Pulp capping

d. Reinforce the restoration

23 / 60

Setting time of alginate can be better controlled by 😕

a. Chemical accelerators and retarders

b. Temperature of water used of mixing

c. Changing water: powder ratio

d. Mixing time

24 / 60

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

a. Peroxide-amine

b. Organic acid-metal ion

c. Diketone-amine

d. Organic acid-peroxide

25 / 60

The cracks formed on the ceramic during cooling because 😕

a. The outer layer cools more rapidly than the interior

b. Due to external forces

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

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

26 / 60

Strength of dental porcelain is dependent on 😕

a. No internal structure

b. Rough

c. Resistance to fusion

d. Composition

27 / 60

The function of gum dammar in inlay wax is 😕

a. Less strength to wax

b. No resistance to carving

c. No smoothness of pattern

d. To improve smoothness of pattern

28 / 60

Noble metal alloys are classified according to their 😕

a. Castability

b. Malleability

c. Dental function

d. Melting temperature

29 / 60

Which of the following is the best choice of restorative material to achieve moderate to high strength, fluorite release, and esthetics ?

a. Compomer

b. Composite

c. Hybrid ionomer

d. Glass ionomer

30 / 60

For each property, list the amalgam type (irregular low-copper, admixed high-copper, and spherical high-copper ) that has the highest value?.

a. Creep irregular high-copper

b. Tensile strength spherical high-copper

c. Creep irregular low-copper

d. 1-hour compressive strength spherical high-copper

31 / 60

Which of the following composites give rough surfaced finish ?

a. Conventional composites

b. Hybrid composites

c. Small particle filled composites

d. Microfilled composites

32 / 60

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

a. Amalgam

b. Unfilled

c. Silicate cement

d. Glass ionomer cement

33 / 60

Acrylic resins are used in which of the following ?

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

b. Posterior inlays

c. Anterior onlays

d. Denture bases

34 / 60

The main advantage of composites compared to silicates cement is 😕

a. Color matching with the tooth structure is excellent

b. High modulus of resilience

c. Practically insoluble in oral fluids

d. Coefficient of thermal expansion close to tooth structure

35 / 60

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

a. Composite restorative resins

b. Acrylic resin

c. Gold alloys

d. Ceramic

36 / 60

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

a. Pure gold

b. Amalgam

c. Composites

d. Silicates

37 / 60

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

a. Acrylic resin

b. Ethyl silicate

c. Styrene-acrylonitrile

d. Polydimethyl siloxane

38 / 60

The desirable quality of porcelain is 😕

a. Translucency

b. Requirement of color

c. Thermal expansion

d. Toughness without brittleness

39 / 60

Which of the following statements is incorrect regarding hydroxyapatite as an implant material ?

a. It is a bio-inert material

b. It is produced in block or granula form

c. It is used for augmenting alveolar ridges of filling bony defects

d. This material in granular form and is difficult

40 / 60

A direct restorative material used frequently to restore a portion of a posterior tooth that is subject to large biting forces would possess which of the following properties ?

a. High strength

b. Esthetics

c. Thermal insulation

d. Ease of casting

41 / 60

Hypersensitivity reactions like contact dermatitis is caused by 😕

a. Polysulfides

b. Addition silicones

c. Polyether

d. Condensation silicones

42 / 60

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

a. No Protein lysing effect

b. High alkalinity

c. Low alkalinity

d. No antibacterial action

43 / 60

Pick out the incorrect statement regarding alginate impressions 😕

a. Is an irreversible hydrocolloid impression material

b. Will take up water and expand if kept wet

c. May exhibit a fluid exudates on the surface as a result of imbibitions

d. Will be shrink as a result of syneresis

44 / 60

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

a. Artificial acrylic teeth are attached

b. They are attached to natural teeth with cements,

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

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

45 / 60

Clinical significance of smear layer :

a. Provides calcium for adhesion of composites

b. Bonded to tooth structure and prevents composite adhesion

c. Improve the strength of the composite

d. Increases the bonding action of the bonding agent

46 / 60

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

a. Type II

b. Type III

c. Type I

d. Type IV

47 / 60

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

a. Modulus of elasticity

b. Polymerization shrinkage

c. Thermal expansion

d. Water sorption

48 / 60

Silver has all the following characteristics except 😕

a. Whitens when added to alloys

b. Silver points serve as a root canal filling material

c. Addition of palladium to silver increases corrosion

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

49 / 60

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

a. Transosteal frames

b. Intramucosal frames

c. Endosseus implants

d. Subperiosteal

50 / 60

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

a. Utility wax

b. Carding wax

c. Boxing wax

d. Beading wax

51 / 60

Commonly used filler in composite is 😕

a. Quartz

b. Aluminum

c. Colloidal silica

d. Glass

52 / 60

Crystalline materials have 😕

a. Well-defined melting

b. Less stable space lattice

c. No well-defined melting

d. No space lattice

53 / 60

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

a. Produces contraction

b. Decreases ductility

c. Hydrolyzes the water if contaminated

d. Decreases the setting time

54 / 60

Stearic acid in impression compound 😕

a. Reduces plasticity

b. Increase setting time

c. Reduces brittleness

d. Reduces flow

55 / 60

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

a. Wall carpeting

b. Amalgam scrap stored in a closed container

c. Floor carpeting

d. Baseboard heating

56 / 60

The byproduct in condensation silicones is 😕

a. Ethyl alcohol

b. Methyl alcohol

c. Butyl alcohol

d. Propyl alcohol

57 / 60

The physical properties most desirable in set amalgam are which of the following ?

a. Higher strength, low creep, low corrosion

b. Higher strength, high creep, low corrosion

c. Higher strength, high creep, high corrosion

d. Low strength, low creep, low corrosion

58 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Difficult to manipulate

b. Maximum details are not produced

c. Cost factor is high

d. Bond between agar and alginate is not very strong

59 / 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

60 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It does not oxidize

b. It is relatively soft and ductile

c. It is low in strength

d. Pure zinc has no application in dentistry

Your score is

The average score is 86%

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