Biomaterial Test

5 votes, 5 avg

164

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 statements is incorrect regarding hydroxyapatite as an implant material ?

a. This material in granular form and is difficult

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

c. It is produced in block or granula form

d. It is a bio-inert material

2 / 60

In dental plaster the main ingredient is 😕

a. Calcium sulfate hemihydarate

b. Calcium anhydrate

c. Calcium sulfate dehydrate

d. Calcium phosphate

3 / 60

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

a. Polyethers

b. Polysulfides

c. Condensation silicones

d. Addition silicones

4 / 60

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

a. Glass ionomer

b. Composite

c. Compomer

d. Hybrid ionomer

5 / 60

Resistance of a liquid to motion is called 😕

a. Creep

b. Viscosity

c. Springiness

d. Diffusion

6 / 60

The product that is formed on the surface of the amalgam restoration and frequently result in discoloration is 😕

a. Gamma II Phase

b. Oxide

c. Gamma I Phase

d. Sulphide

7 / 60

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

a. Pulp inflammation

b. Secondary caries

c. Porosity in restoration

d. Sagging of restoration

8 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. 45-600C

b. 37-450C

c. Far below the oral temperature

d. 100C higher than mouth temperature

9 / 60

Setting of plaster of Paris is a result of 😕

a. Solubility difference between hemihydrates and dehydrate

b. Loss of water from hemihydrates

c. Indirect interaction between hemihydrates

d. Interaction between hemihydrates and water

10 / 60

In visible light-cured composites photo initiator molecule is 😕

a. Bis-phenol-A

b. Benzoyl methyl ether

c. Camphoroquinone

d. Toluidine

11 / 60

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

a. Porcelain will not bond with metal

b. Porcelain will wear off

c. Porcelain will crack on cooling

d. Porcelain will provide good shade

12 / 60

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

a. Thermal expansion

b. Water sorption

c. Polymerization shrinkage

d. Modulus of elasticity

13 / 60

Which of the following represents the maximum safe concentration of mercury vapor in the breathing zone for a 40-hour workweek ?

a. All are corrects

b. 30 ng Hg/m3 of air

c. 0.05 mg Hg/m3 of air

d. 100 ng Hg/m3 of air

14 / 60

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

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

b. Reduces burning sensation of paste

c. To increase setting time

d. Has a better reaction with zinc oxide

15 / 60

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

a. Cu-Sn

b. Sn-Hg

c. Ag-Hg

d. Ag-Su

16 / 60

Sulfur contamination from natural latex gloves inhibits the setting of 😕

a. Zinc oxide eugenol impression paste

b. Polyvinyl siloxane

c. Alginate

d. Polyether

17 / 60

Once amalgamation has occurred, which of the following is true of mercury ?

a. Has the toxic properties of unreacted mercury

b. Composite restorative resins

c. Is combined primarily with silver

d. Can form at the surface of amalgam restorations if heated to 0° C

18 / 60

Carnauba wax is preferred to candelilla wax as 😕

a. It is harder and has less flow

b. It is sticky

c. It provides luster to the pattern

d. It has low melting temperature

19 / 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

20 / 60

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

a. Direct resin-filling material

b. Silicate

c. Amalgam

d. Zinc phosphate

21 / 60

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

a. Sn-Hg

b. Cu-Sn

c. Ag-Su

d. Ag-Hg

22 / 60

Which of the following base is contraindicated for composites ?

a. Glass ionomer cement

b. Zinc phosphate

c. Calcium hydroxide

d. Zinc oxide eugenol

23 / 60

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

a. Condensation silicones

b. Polyether

c. Polysulfides

d. Addition silicones

24 / 60

The catalyst used for condensation silicones is 😕

a. Stannous octoate

b. Oleic acid

c. Platinum

d. Lead dioxide

25 / 60

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

a. Gold alloy

b. Composite resin

c. Amalgam

d. Porcelain

26 / 60

The most commonly employed alloy combination for use in implants is 😕

a. Titanium-platinum-aluminum alloy

b. Titanium-molybdenum-vanadium alloy

c. Titanium-aluminum-vanadium alloy

d. Platinum-aluminum-vanadium alloy

27 / 60

Binder in the phosphate investment is 😕

a. Cristobalite

b. Manganese dioxide

c. Magnesium oxide and monoammonium phosphate

d. Phosphoric acid

28 / 60

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

a. Addition silicone

b. Polysulfide

c. Condensation silicone

d. Polyether

29 / 60

Noble metal alloys are classified according to their 😕

a. Dental function

b. Castability

c. Melting temperature

d. Malleability

30 / 60

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

a. Acrylic resin

b. Ceramic

c. Gold alloys

d. Composite restorative resins

31 / 60

Greening effect of porcelain is due to 😕

a. Silver

b. Golde

c. Palladium

d. Platinum

32 / 60

In UV curing system the activator employed is 😕

a. Methyl methacrylate

b. Dibutyl phthalate

c. Benzoin methyl ether

d. Hydroquinone

33 / 60

The main resin constituent of polishable composite resin is 😕

a. Cyanoacrylate

b. Polycaronate

c. Urethane dimethacrylate

d. Polymethyl methacrylate

34 / 60

Commonly used filler in composite is 😕

a. Quartz

b. Glass

c. Aluminum

d. Colloidal silica

35 / 60

The most commonly used implant type presently is 😕

a. Subperiosteal

b. Endosseous

c. Transosteal implant

d. Intramucosal implant

36 / 60

Crystalline materials have 😕

a. Well-defined melting

b. Less stable space lattice

c. No space lattice

d. No well-defined melting

37 / 60

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

a. Composite resin

b. Gold alloys

c. Ceramic

d. Amalgam

38 / 60

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

a. Ceramic

b. Glass ionomer

c. Waxe

d. Gold

39 / 60

Crystal structures of metals are all the following except 😕

a. Circular

b. Cubic

c. Monoclinic

d. Tetragonal

40 / 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

41 / 60

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

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

b. Artificial acrylic teeth are attached

c. They are attached to natural teeth with cements,

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

42 / 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. Proportioning mercury and alloy into a friction-fit capsule

c. Triturating precapsulated alloy and mercury

d. Mixing in a mortar and pestle

43 / 60

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

a. Styrene-acrylonitrile

b. Acrylic resin

c. Polydimethyl siloxane

d. Ethyl silicate

44 / 60

A cavity varnish used for lining the preparation for a dental amalgam restoration will :

a. Provide electrical insulation

b. Provide thermal insulation

c. Reduce early marginal leakage tooth structure

d. Provide strength of amalgam

45 / 60

The most effective cement in stimulating tertiary dentin is 😕

a. Zinc silicophoshpate

b. Calcum hydroxide

c. Polycardoxylate

d. Zinc phosphate

46 / 60

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

a. They cannot be soldered or welded

b. Their hardness is comparable to stainless steel

c. They have excellent tarnish and corrosion resistance

d. They can be heat treated

47 / 60

In the cavities which are more than 2mm deep a light-cured restoration is 😕

a. Cured for longer period

b. Fifth generation bonding agent should be applied

c. Not indicated

d. Restoration should be build in increments

48 / 60

Biting force in the molar region ranges from 😕

a. 400-890 N

b. 1000-1300 N

c. 600-1000 N

d. 900-1000 N

49 / 60

Dental porcelains are manufactured by a process termed as 😕

a. Vulcanizing

b. Fusing

c. Sintering

d. Fritting

50 / 60

Contamination of zinc-containing amalgam by moisture during triturating or condensation :

a. Has no appreciable effect on properties except to the susceptibility to tarnish

b. Results in a sharp decrease in flow

c. Results in a marked expansion

d. Increases the setting time

51 / 60

Porosity in denture base resins can be due to 😕

a. Adequate mixing of liquid and powder components

b. Excess heating of resin above its boiling point

c. Applying sufficient pressure during polymerization

d. Well flasking of wax pattern

52 / 60

Montan waxes have the following properties except 😕

a. Have low melting points of 42oC

b. Hard, brittle and lustrous

c. Obtained by extraction from lignite

d. Are mineral waxes

53 / 60

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

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

b. Should be brittle

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

d. Should bond with dental porcelain

54 / 60

The main ingredient of casting waxes is 😕

a. Gum dammar

b. Candellila wax

c. Paraffin wax

d. Carnauba wax

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

d. They also are know as GIC

56 / 60

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

a. Ductility

b. Fatigue

c. Creep

d. Resilience

57 / 60

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

a. Decreases setting time

b. Does not alter setting time

c. Depends on rate of mixing

d. Increases setting time

58 / 60

Softening of impressing compound is best accomplished by 😕

a. Open flame

b. Oil bath

c. Water bath

d. Dry heat

59 / 60

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

a. Toughness

b. Brittleness

c. Hardness

d. Springiness

60 / 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

Your score is

The average score is 86%

Any comments?

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

និស្សិតអាចប្រាប់មកកាន់ពួកយើងបានដើម្បីកែកំហុស ឬអំពីបញ្ហាដោយអចេតនាណាមួយដែលកើតមានកំឡុងពេលធ្វើតេស្ត