Biomaterial Test

5 votes, 5 avg

You will have 60 minutes to complete all the questions. After the timer reaches 60 minutes, the exam will end and be saved automatically. Good luck! *Fingers crossed*

The timer has been reached. The exam has now been terminated and saved.

Biomaterial Test

1 / 60

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

a. Small particles

b. Conventional composites

c. Hybrid composites

d. Microfilled composites

2 / 60

Resistance of a liquid to motion is called 😕

a. Springiness

b. Viscosity

c. Creep

d. Diffusion

3 / 60

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

a. Addition silicone

b. Polyether

c. Condensation silicone

d. Polysulfide

4 / 60

The main function of zinc in amalgam is 😕

a. To prevent the creep

b. To produce delayed expansion

c. To increase the shelf-life of an amalgam

d. To increase the longevity of amalgam after setting

5 / 60

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

a. 3:1

b. 1:2

c. 2:1

d. 1:3

6 / 60

Polyether is different from other elastomers in the following aspects 😕

a. Hydropholic in nature

b. High stiffiness

c. Can not be used as light cure material

d. Low stiffness

7 / 60

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

a. Hardness

b. Brittleness

c. Springiness

d. Toughness

8 / 60

When the gold content of gold alloys increases 😕

a. The hardness decrease

b. The corrosion resistance increases

c. The percentage elongation decrease

d. Ductility decrease

9 / 60

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

a. Providing strength to the restoration

b. Compensating polymerization shrinkage

c. Saving the application of bonding agent

d. Achieving complete polymerization

10 / 60

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

a. Poly (methyl methacrylate)

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

c. Polystyrene

d. Pheyl methacrylate

11 / 60

In an alloy oxygen scavenger is 😕

a. Copper

b. Palladium

c. Silver

d. Zinc

12 / 60

Impression plaster is a 😕

a. Mucocompressive material

b. Reversible impression material

c. Thermoplastic material

d. Mucostatic material

13 / 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. Dental amalgam is a mixture of silver alloys and mercury.

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

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

14 / 60

Gold with high percentage elongation is best for 😕

a. To improve the castability

b. Increase the bond strength

c. To revert sagging during firing

d. To remove metallic oxide

15 / 60

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

a. 1-hour compressive strength spherical high-copper

b. Tensile strength spherical high-copper

c. Creep irregular high-copper

d. Creep irregular low-copper

16 / 60

Setting time of alginate can be better controlled by 😕

a. Temperature of water used of mixing

b. Changing water: powder ratio

c. Chemical accelerators and retarders

d. Mixing time

17 / 60

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

a. Floor carpeting

b. Baseboard heating

c. Wall carpeting

d. Amalgam scrap stored in a closed container

18 / 60

Main disadvantage of denture base soft reliner is 😕

a. It can not lead to fungal growth

b. It can be cleaned properly

c. It can not lead to cleaned property

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

19 / 60

Which of the following composites give rough surfaced finish ?

a. Hybrid composites

b. Conventional composites

c. Small particle filled composites

d. Microfilled composites

20 / 60

For luting purpose, the film thickness should be 😕

a. ideally 100 μm

b. minimum 50 μm

c. up to 75 μm

d. 25 μm or less

21 / 60

The main advantage of composites compared to silicates cement is 😕

a. High modulus of resilience

b. Practically insoluble in oral fluids

c. Coefficient of thermal expansion close to tooth structure

d. Color matching with the tooth structure is excellent

22 / 60

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

a. Microfilled

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

c. All are correct

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

23 / 60

Clinical significance of smear layer :

a. Increases the bonding action of the bonding agent

b. Provides calcium for adhesion of composites

c. Bonded to tooth structure and prevents composite adhesion

d. Improve the strength of the composite

24 / 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 has poor tensile strength

d. It does not form reparative dentin

25 / 60

The constituent that acts as a binder in the investment is 😕

a. Silica

b. Quartz

c. Water

d. Gypsum

26 / 60

Pick out the incorrect statement regarding alginate impressions 😕

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

b. Is an irreversible hydrocolloid impression material

c. Will be shrink as a result of syneresis

d. Will take up water and expand if kept wet

27 / 60

In UV curing system the activator employed is 😕

a. Hydroquinone

b. Dibutyl phthalate

c. Methyl methacrylate

d. Benzoin methyl ether

28 / 60

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

a. All of them should be heated before using

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

c. All of them are polymers

d. All of them are a result of secondary reaction

29 / 60

In dental porcelains metallic oxides provide 😕

a. Color and increases the strength

b. Color but decreases the strength

c. Color and provides refractile property

d. Provides refractile property and increases strength

30 / 60

Crystalline materials have 😕

a. No space lattice

b. No well-defined melting

c. Less stable space lattice

d. Well-defined melting

31 / 60

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

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

b. Artificial acrylic teeth are attached

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

d. They are attached to natural teeth with cements,

32 / 60

A measure of ductility of a material is referred to as 😕

a. Yield strength

b. Percentage elongation

c. Flexibility

d. Proportional limit

33 / 60

Stearic acid in impression compound 😕

a. Increase setting time

b. Reduces plasticity

c. Reduces brittleness

d. Reduces flow

34 / 60

One of the following statements which one is incorrect regarding addition silicones 😕

a. No evolution of any byproduct under all circumstances

b. Can be used in automixing devices

c. Dimensionally stable even after 1 week

d. Undetectable distortion on removal

35 / 60

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

a. Iatrogenesis

b. Teratogenesis

c. Carcinogenesis

d. Biocompatibility

36 / 60

In alginate impression the final gel is 😕

a. Sodium sulphate

b. Calcium sulphate

c. Calcium alginate

d. Sodium alginate

37 / 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.

38 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It is sticky

b. It has low melting temperature

c. It is harder and has less flow

d. It provides luster to the pattern

39 / 60

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

a. Peroxide-amine

b. Organic acid-peroxide

c. Organic acid-metal ion

d. Diketone-amine

40 / 60

Stiffness of the material with passage of time is maximum in 😕

a. Polysulfides

b. Condensation silicones

c. Addition silicones

d. Polyether

41 / 60

The cavity for a GIC restoration is preconditioned with 😕

a. Phosphoric acid for 60 seconds

b. Phosphoric acid for 10 seconds

c. Polyacrylic acid for 60 seconds

d. Polyacrylic acid for 10 seconds

42 / 60

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

a. Higher strength, high creep, high corrosion

b. Higher strength, low creep, low corrosion

c. Low strength, low creep, low corrosion

d. Higher strength, high creep, low corrosion

43 / 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. Ease of casting

d. Thermal insulation

44 / 60

Light source in the curing unit is usually 😕

a. Sun light

b. Tungsten halogen light bulb

c. Ultraviolet light bulb

d. Infra red bulb

45 / 60

Greening effect of porcelain is due to 😕

a. Palladium

b. Platinum

c. Silver

d. Golde

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

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

47 / 60

Which one of the following is not a criterion for a failed high-copper dental amalgam restorations ?

a. Wear facets along the occlusal contach areas

b. Creep of the restoration out of the cavity preparation in proximal areas

c. Marginal ditching along occlusal margins

d. Micrographs of alloys particles.

48 / 60

A glaze is placed over the finished composite restoration to 😕

a. No provide a better peripheral seal

b. To change the shade

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

d. To reduce surface porosities

49 / 60

Setting of plaster of Paris is a result of 😕

a. Interaction between hemihydrates and water

b. Solubility difference between hemihydrates and dehydrate

c. Indirect interaction between hemihydrates

d. Loss of water from hemihydrates

50 / 60

The purpose of burnishing the amalgam after condensation is to 😕

a. To prevent recurrent carries

b. To reduce discoloration

c. To reduce gamma II particule

d. Reduce surface microporosities

51 / 60

Crystal structures of metals are all the following except 😕

a. Circular

b. Monoclinic

c. Cubic

d. Tetragonal

52 / 60

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

a. Porcelain will provide good shade

b. Porcelain will crack on cooling

c. Porcelain will not bond with metal

d. Porcelain will wear off

53 / 60

Dispensing composite resins using a syringe is advantageous because it 😕

a. Increases surface smoothness

b. Decreases air voids in the restoration

c. Increases strength and abrasive resistance

d. Conserves the material

54 / 60

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

a. Sn-Hg

b. Cu-Sn

c. Ag-Hg

d. Ag-Sn

55 / 60

Most common use of Zinc oxide eugenol paste 😕

a. As interocclusal record material

b. Wash impression for edentulous patients

c. Surgical paste

d. Dual impression for Partially edentulous patients

56 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Bond between agar and alginate is not very strong

b. Cost factor is high

c. Difficult to manipulate

d. Maximum details are not produced

57 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Toluidine

b. Bis-phenol-A

c. Camphoroquinone

d. Benzoyl methyl ether

58 / 60

The fluoride release from glass ionomer cement is 😕

a. 0.075 mg during the first month

b. 0.005 mg during the first week

c. 0.75 mg during the first week

d. 0.0005 mg during the first month

59 / 60

In dental plaster the main ingredient is 😕

a. Calcium phosphate

b. Calcium anhydrate

c. Calcium sulfate hemihydarate

d. Calcium sulfate dehydrate

60 / 60

Silver has all the following characteristics except 😕

a. Silver points serve as a root canal filling material

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

c. Whitens when added to alloys

d. Addition of palladium to silver increases corrosion

Your score is

The average score is 62%

Any comments?

Any problems/errors or mistakes found while testing, please let us know for modification!

និស្សិតអាចប្រាប់មកកាន់ពួកយើងបានដើម្បីកែកំហុស ឬអំពីបញ្ហាដោយអចេតនាណាមួយដែលកើតមានកំឡុងពេលធ្វើតេស្ត