Biomaterial Test

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Biomaterial Test

1 / 60

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

a. Composite restorative resins

b. Gold alloys

c. Acrylic resin

d. Ceramic

2 / 60

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

a. Hight ductility of metal

b. Chemical bonding

c. High malleafility of metal

d. Chemico-mechenical bonding

3 / 60

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

a. Brittleness

b. Springiness

c. Hardness

d. Toughness

4 / 60

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

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

b. It cannot be polished

c. It cause abrasion and wearing of opposing tooth surface

d. It has low affinity for resin matrix

5 / 60

Gypsum investments should not be heated above 😕

a. 17000C

b. 7000C

c. 10000C

d. 4500C

6 / 60

When a mechanical device is used for mixing addition silicones 😕

a. There is no greater uniformity in proportioning and mixing

b. Mixing time is long

c. Mixing time is reduced

d. More possibilities of contamination

7 / 60

The energy absorbed by a material when it is stressed to its proportional limit is 😕

a. Toughness

b. Resilience

c. Impact strength

d. Flexibility

8 / 60

Glass ionomer cenment is not recommended for 😕

a. Class I restoration

b. Class IV resoration

c. Class III restoration

d. Class V restoration

9 / 60

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

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

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

c. They are attached to natural teeth with cements,

d. Artificial acrylic teeth are attached

10 / 60

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

a. Amalgam

b. Silicate

c. Direct resin-filling material

d. Zinc phosphate

11 / 60

The byproduct in condensation silicones is 😕

a. Butyl alcohol

b. Methyl alcohol

c. Ethyl alcohol

d. Propyl alcohol

12 / 60

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

a. Toughness

b. Modulus of elasticity

c. Flexibility

d. Resilience

13 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. Far below the oral temperature

b. 100C higher than mouth temperature

c. 37-450C

d. 45-600C

14 / 60

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

a. Water sorption

b. Modulus of elasticity

c. Polymerization shrinkage

d. Thermal expansion

15 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Deflasking

b. Packing

c. Polishing

d. Curing

16 / 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. 0.05 mg Hg/m3 of air

b. 100 mg Hg/m3 of air

c. 0.04 mg Hg/m3 of air

d. 30 mg Hg/m3 of air

17 / 60

Which of the following statements about compomers are true ?

a. They typically are recommended for class II restorations.

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

c. They also are know as GIC

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

18 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Decreases air voids in the restoration

b. Conserves the material

c. Increases strength and abrasive resistance

d. Increases surface smoothness

19 / 60

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

a. Microfilled composites

b. Small particles

c. Conventional composites

d. Hybrid composites

20 / 60

The reason for hydroxyapatite coating on implant biomaterials is 😕

a. Prolonged healing time

b. Presence of fibrous tissue

c. Greater bony opposition

d. Lesser bony apposition

21 / 60

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

a. It is produced in block or granula form

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

c. This material in granular form and is difficult

d. It is a bio-inert material

22 / 60

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

a. Depends on rate of mixing

b. Increases setting time

c. Does not alter setting time

d. Decreases setting time

23 / 60

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

a. Sn-Hg

b. Ag-Sn

c. Ag-Hg

d. Cu-Sn

24 / 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. Decreased polymerization of the resin

c. Subsequent oxidation of the tertiary amine

d. Increased solubility of the resin

25 / 60

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

a. Beading wax

b. Carding wax

c. Boxing wax

d. Utility wax

26 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Sintering

b. Fritting

c. Vulcanizing

d. Fusing

27 / 60

Amalgam is less prone to corrosion 😕

a. If it contains 4-6% of copper

b. If it contains zinc

c. If devoid of the gamma 2 phase

d. If it contains 25-27% of tin

28 / 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

29 / 60

Which of the following composites give rough surfaced finish ?

a. Hybrid composites

b. Microfilled composites

c. Small particle filled composites

d. Conventional composites

30 / 60

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

a. Silicate cement

b. Glass ionomer cement

c. Unfilled

d. Amalgam

31 / 60

Conventional dental amalgam alloy contains 😕

a. Silver, mercury, copper and zinc

b. Silver, tin, copper and zinc

c. Silver, mercury, copper and mercury

d. Silver, tin, palladium and zinc

32 / 60

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

a. Ceramic

b. Amalgam

c. Gold alloy

d. Silver alloys

33 / 60

Which of the following uses a hardened steel ball indenting tool ?

a. Brinell hardness test

b. Knoop hardness test

c. Rockwell hardness test

d. Vichers hardness test

34 / 60

Which of these statements are correct in terms of preparing a correctly triturated mass of amalgam ?

a. An undertriturated mass is crumbly and dull.

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

c. An overmixed mass is removed readily from the capsule but is soupy in appearance.

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

35 / 60

The main ingredient of casting waxes is 😕

a. Gum dammar

b. Carnauba wax

c. Candellila wax

d. Paraffin wax

36 / 60

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

a. Composite resin

b. Amalgam

c. Ceramic

d. Gold alloys

37 / 60

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

a. Glass ionomer

b. Waxe

c. Ceramic

d. Gold

38 / 60

If the light cure resin is curd in increments, it helps in 😕

a. Saving the application of bonding agent

b. Providing strength to the restoration

c. Achieving complete polymerization

d. Compensating polymerization shrinkage

39 / 60

Strength of dental porcelain is dependent on 😕

a. No internal structure

b. Resistance to fusion

c. Composition

d. Rough

40 / 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. Will take up water and expand if kept wet

d. Is an irreversible hydrocolloid impression material

41 / 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

42 / 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. Ease of casting

b. Thermal insulation

c. High strength

d. Esthetics

43 / 60

Minimum light exposure time for composite resins should be 😕

a. 20 sec

b. 40 sec

c. 10 sec

d. 5 sec

44 / 60

Crystalline materials have 😕

a. No space lattice

b. Well-defined melting

c. Less stable space lattice

d. No well-defined melting

45 / 60

Oil of clove is sometimes used in preference to eugenal in ZOE paste because :

a. Has a better reaction with zinc oxide

b. It increases mixing property of paste and therefore improves impression recorded

c. Reduces burning sensation of paste

d. To increase setting time

46 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Hydropholic in nature

b. Low stiffness

c. Can not be used as light cure material

d. High stiffiness

47 / 60

In dental porcelains metallic oxides provide 😕

a. Provides refractile property and increases strength

b. Color and increases the strength

c. Color and provides refractile property

d. Color but decreases the strength

48 / 60

Light source in the curing unit is usually 😕

a. Sun light

b. Tungsten halogen light bulb

c. Infra red bulb

d. Ultraviolet light bulb

49 / 60

Following are the functions of impression compound except 😕

a. To make special tray for final impression

b. To record mucostatic impressions

c. To make impression of edentulous ridge

d. To make individual die impression with copper band

50 / 60

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

a. Should be brittle

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

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

d. Should bond with dental porcelain

51 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Alginate

b. Polyether

c. Polyvinyl siloxane

d. Zinc oxide eugenol impression paste

52 / 60

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

a. Porosity in restoration

b. Pulp inflammation

c. Secondary caries

d. Sagging of restoration

53 / 60

Elgiloy arch wire is 😕

a. Optical fiber arch wire

b. β-titanium arch wire

c. Gold alloy

d. Cobalt-chromium-nickel alloy

54 / 60

Resistance of a liquid to motion is called 😕

a. Viscosity

b. Springiness

c. Diffusion

d. Creep

55 / 60

The following statements about dental porcelains are true except 😕

a. Crystalline nature

b. Undergoes discoloration

c. Undergoes firing shrinkage

d. It is brittle in nature

56 / 60

Noble metal alloys are classified according to their 😕

a. Castability

b. Melting temperature

c. Malleability

d. Dental function

57 / 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. Composite restorative resins

c. Has the toxic properties of unreacted mercury

d. Is combined primarily with silver

58 / 60

Which of the following statements about laboratory composites are true ?

a. Restorations prepared from laboratory composites typically are cemented with zinc phosphate cement.

b. Bridge prepared from laboratory composites require a metal substructure.

c. Fiber reinforcement increases their strength but decrease their rigidity.

d. Curing using light, heat, and pressure increase the wear resistance.

59 / 60

Crystal structures of metals are all the following except 😕

a. Monoclinic

b. Circular

c. Cubic

d. Tetragonal

60 / 60

The strain at which the plastic strain develops may be represented by 😕

a. Yield strength, tensile strength, toughness

b. Elastic limit, modulus of elasticity, tensile strength

c. Toughness, rigidity, resilience

d. Elastic limit, yield strength, proportional limit

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