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

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

a. Undetectable distortion on removal

b. No evolution of any byproduct under all circumstances

c. Dimensionally stable even after 1 week

d. Can be used in automixing devices

2 / 60

Oxalates, carbonates, potassium, trisodium phosphates are added to alginate as 😕

a. Reactors

b. Retarders

c. Fillers

d. Accelerators

3 / 60

The cracks formed on the ceramic during cooling because 😕

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

b. Due to external forces

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

d. The outer layer cools more rapidly than the interior

4 / 60

Which of the following is called periphery wax ?

a. Utility wax

b. Beading wax

c. Sticky wax

d. Bite registration wax

5 / 60

Most commonly used pit and fissure sealant is 😕

a. Bis-GMA resin

b. Filled acrylic

c. Polyurethane

d. Unfilled acrylic

6 / 60

The light from the visible light curing unit can cause 😕

a. Iritis

b. Retinal damage

c. Corneal ulceration

d. Cataract

7 / 60

Stearic acid in impression compound 😕

a. Reduces brittleness

b. Reduces flow

c. Increase setting time

d. Reduces plasticity

8 / 60

Strength of dental porcelain is dependent on 😕

a. Composition

b. Rough

c. No internal structure

d. Resistance to fusion

9 / 60

Softening of impressing compound is best accomplished by 😕

a. Dry heat

b. Water bath

c. Oil bath

d. Open flame

10 / 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. Wall carpeting

d. Baseboard heating

11 / 60

The most commonly used implant type presently is 😕

a. Subperiosteal

b. Transosteal implant

c. Endosseous

d. Intramucosal implant

12 / 60

Acrylic resins are used in which of the following ?

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

b. Denture bases

c. Anterior onlays

d. Posterior inlays

13 / 60

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

a. Condensation silicone

b. Polyether

c. Polyvinyl siloxane

d. Polysulfied

14 / 60

Main disadvantage of laminate technique of making impression is : ?

a. Maximum details are not produced

b. Difficult to manipulate

c. Bond between agar and alginate is not very strong

d. Cost factor is high

15 / 60

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

a. Polymerization shrinkage

b. Modulus of elasticity

c. Water sorption

d. Thermal expansion

16 / 60

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

a. Ag-Hg

b. Ag-Su

c. Cu-Sn

d. Sn-Hg

17 / 60

A glaze is placed over the finished composite restoration to 😕

a. No provide a better peripheral seal

b. To change the shade

c. To reduce surface porosities

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

18 / 60

Higher mercury left in an amalgam leads to which of the following ?

a. Low corrosion

b. Higher strength

c. Higher creep

d. High corrosion

19 / 60

KHN of enamel is 😕

a. 100

b. 600

c. 90-100

d. 300

20 / 60

Nickel sensitivity in the general population is 😕

a. 3% for women

b. 11% for women

c. 3% for men

d. 1% in the overall population

21 / 60

In dental porcelains metallic oxides provide 😕

a. Color and provides refractile property

b. Color but decreases the strength

c. Provides refractile property and increases strength

d. Color and increases the strength

22 / 60

When a mechanical device is used for mixing addition silicones 😕

a. Mixing time is long

b. More possibilities of contamination

c. There is no greater uniformity in proportioning and mixing

d. Mixing time is reduced

23 / 60

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

a. Low strength, low creep, low corrosion

b. Higher strength, low creep, low corrosion

c. Higher strength, high creep, high corrosion

d. Higher strength, high creep, low corrosion

24 / 60

Metal has the following properties except 😕

a. Pure metals are not useful in dentistry

b. Electroplated silver and copper are used in dies

c. Metal is any element that ionizes positively in solution

d. All metals do not have same degrees of strength and plasticity

25 / 60

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

a. Acrylic resin

b. Polydimethyl siloxane

c. Ethyl silicate

d. Styrene-acrylonitrile

26 / 60

The gelation temperature of agar hydrocolloid impression material should be 😕

a. Far below the oral temperature

b. 37-450C

c. 45-600C

d. 100C higher than mouth temperature

27 / 60

Gypsum investments should not be heated above 😕

a. 17000C

b. 7000C

c. 4500C

d. 10000C

28 / 60

Biting force in the molar region ranges from 😕

a. 400-890 N

b. 600-1000 N

c. 1000-1300 N

d. 900-1000 N

29 / 60

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

a. Polysulfides

b. Polyether

c. Addition silicones

d. Condensation silicones

30 / 60

Ideal metal used for electroplating polysulfide impression is 😕

a. Nickel

b. Copper

c. Cobalt

d. Silver

31 / 60

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

a. Hydrolyzes the water if contaminated

b. Decreases ductility

c. Produces contraction

d. Decreases the setting time

32 / 60

Calcium hydroxide is used for 😕

a. Reinforce the restoration

b. To prevent recurrent caries

c. Reduce maginal leakage

d. Pulp capping

33 / 60

Spot out incorrect statement regarding zinc in dentistry 😕

a. It does not oxidize

b. It is relatively soft and ductile

c. Pure zinc has no application in dentistry

d. It is low in strength

34 / 60

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

a. Titanium-molybdenum-vanadium alloy

b. Titanium-platinum-aluminum alloy

c. Platinum-aluminum-vanadium alloy

d. Titanium-aluminum-vanadium alloy

35 / 60

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

a. 100 ng Hg/m3 of air

b. 0.05 mg Hg/m3 of air

c. 30 ng Hg/m3 of air

d. All are corrects

36 / 60

Montan waxes have the following properties except 😕

a. Are mineral waxes

b. Obtained by extraction from lignite

c. Hard, brittle and lustrous

d. Have low melting points of 42oC

37 / 60

Which of the following materials are used for dental implants ?

a. Metal alloys

b. Cobalt and chromium alloys

c. Gold alloys

d. Titanium

38 / 60

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

a. Diketone-amine

b. Peroxide-amine

c. Organic acid-peroxide

d. Organic acid-metal ion

39 / 60

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

a. Amalgam

b. Zinc phosphate

c. Direct resin-filling material

d. Silicate

40 / 60

Impression plaster is a 😕

a. Thermoplastic material

b. Reversible impression material

c. Mucostatic material

d. Mucocompressive material

41 / 60

Glass ionomer cenment is not recommended for 😕

a. Class III restoration

b. Class IV resoration

c. Class V restoration

d. Class I restoration

42 / 60

In dental plaster the main ingredient is 😕

a. Calcium anhydrate

b. Calcium sulfate hemihydarate

c. Calcium sulfate dehydrate

d. Calcium phosphate

43 / 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. Compomer

c. Composite

d. Hybrid ionomer

44 / 60

Which of the following statements about laboratory composites are true ?

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

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

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

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

45 / 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 are polymers

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

d. All of them should be heated before using

46 / 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. Esthetics

c. High strength

d. Thermal insulation

47 / 60

The maximum warpage of acrylic denture occurs during 😕

a. Packing

b. Deflasking

c. Curing

d. Polishing

48 / 60

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

a. Ag-Hg

b. Ag-Su

c. Sn-Hg

d. Cu-Sn

49 / 60

Crystal structures of metals are all the following except 😕

a. Monoclinic

b. Cubic

c. Circular

d. Tetragonal

50 / 60

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

a. Flexibility

b. Proportional limit

c. Percentage elongation

d. Yield strength

51 / 60

When the gold content of gold alloys increases 😕

a. Ductility decrease

b. The percentage elongation decrease

c. The corrosion resistance increases

d. The hardness decrease

52 / 60

Amalgam is less prone to corrosion 😕

a. If it contains zinc

b. If devoid of the gamma 2 phase

c. If it contains 4-6% of copper

d. If it contains 25-27% of tin

53 / 60

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

a. Gold alloy

b. Metal

c. Amalgam

d. Composite resin

54 / 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. Artificial acrylic teeth are attached

d. They are attached to natural teeth with cements,

55 / 60

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

a. Composites

b. Amalgam

c. Pure gold

d. Silicates

56 / 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. Creep irregular high-copper

c. Creep irregular low-copper

d. Tensile strength spherical high-copper

57 / 60

Adhesion in composites is due to 😕

a. True chemical bonding to tooth structure

b. Presence of smear layer

c. Mechanical interlocking

d. Cohesion

58 / 60

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

a. Gold alloys

b. Composite restorative resins

c. Acrylic resin

d. Ceramic

59 / 60

Zinc oxide eugenal impression should be removed from oral cavity :

a. When the material is glossy

b. When it can be easily indented by a blunt instrument

c. When the material cannot be intended by a blunt instrument

d. Exactly after four minutes after kneading

60 / 60

Gold with high percentage elongation is best for 😕

a. To remove metallic oxide

b. Increase the bond strength

c. To improve the castability

d. To revert sagging during firing

Your score is

The average score is 0%

Any comments?

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

និស្សិតអាចប្រាប់មកកាន់ពួកយើងបានដើម្បីកែកំហុស ឬអំពីបញ្ហាដោយអចេតនាណាមួយដែលកើតមានកំឡុងពេលធ្វើតេស្ត