Dental Materials III → Dentist → DENTAL MATERIALS

#1. What is the function of feldspar during preparation of dental porcelain of a metal ceramic Crown?

Feldspar forms a glassphase that is able to soften and flow slightly at porcelain firing temperature

It decreases viscosity of ceramic material so that it can be applied on the metal substructure with ease

Feldspar due to its particle size interrupts crack propagation in the dental porcelain

Feldspar forms a carbon layer that flows at porcelain firing temperature

Feldspar helps to prevent porcelain cracking

#2. Which one of the following is the safest and most reliable method of regulating setting time of gypsum products?

Altering the water and powder ratio

Controlling the temperature of water to be used for mixing

Speed of hand spatulation

Length of hand spatulation

Adding salt in mixing

#3. Which of the following cements bonds to tooth structure, has an anticariogenic effect, has a degree of translucency and does not irritate the pulp?

Polycarboxylate cement

Resin cement

Silicate Cemenet

Glass ionomer cement

Zinc phosphate cement

#4. Which of the following gases used for soldering purposes has the highest temperature?

Hydrogen

Natural gas

Acetylene

Oxygen

Carbon oxide

#5. Setting expansion of casting investment is approximately:

0.1-0.2%

0.1-0.5%

0.8-1%

1.1-1.7%

1.7%-2%

#6. Cement extensively used for attachment of orthodontic brackets to teeth is.

Silicate cement

Resin cement

Glass ionomer cement

Copper oxide cement

ZnO Eugenol cement

#7. The stainless steel loses its resistance to corrosion if heated to a high temperature because:

Precipitation of chromium carbide

Precipitation of carbon carbide

Precipitation of iron carbide

Precipitation of nickle carbide

Precipitation of cohalt carbide

#8. Fillers are added to composite resin to:

Increase working time

Increase coefficient of thermal expansion

Inhibit matrix deformation

B+C

Decrease working time

#9. What is trituration

Surface discoloration of metal

Mixing of amalgam alloy with mercury

Same as erosion

Same as corrosion

Mixing of allow particles

#10. Regarding zinc phosphate cements:

Powder and liquid are mixed on cold glass slab

Powder and liquid are mixed on hot glass slab

Zinc phosphate cements have endothermic reactions

The cement is mixed on a waxed paper mixing pod

Retention is via chemical bonding

#11. The cement which has antibacterial property is:

Copper oxide cement

Glass informer cement

Polycarboxylate cement

Zinc phosphate cement

Zinc oxide Eugenol cement

#12. Most common drawback of amalgam restoration is:

Secondary expansion

Porosity

Marginal break-down

Contraction on setting

Contraction away from margins

#13. Regarding Glass ionomers:

The powder is methyl methacrylate

The powder is an aluminosilicate glass

They release mercury

They are highly irritant to pulp

Following initial placement they should not be protected from dehydration

#14. KHN of enamel is:

90-100

100.50

300

600

60-90

#15. Regarding alginate impression material:

Alginate impression material contains sodium phosphate to act as an accelerator

The set alginate impression is a hydrocolloid gel

The impression is stored in water to prevent inhibition

Alginate impression is powered after 2 hours

The thicker the mixture of alginate results in greater flexibility

#16. Which of the following impression materials is elastic?

Impression compound

Zinc oxide – Eugenol paste

Wax

Polyether rubber base

Low fusing compound

#17. Which part of an amalgam restoration has the highest mercury concentration?

Marginal area

Centre of the restoration

Pulpal area

Proximal surface of restoration

Inclined plane

#18. Activating compound for visible light curing system:

Hycroquinone

Ubiquinone

Camphoquinone

Benzoin methyl ether

Patasium oxide

#19. The knoop hardness number of which one of the following materials is closest to that of dentin (KHN 65)?

Tooth enamel

Amalgam

Pure Gold

Silicate cement

Dentine

#20. Contraction away from margins.

1:1

2:1

1:2

1:3

1:4

#21. Which of the following statements relates best regarding cavity varnish?

Varnishes are synthetic resins dissolved in acetone

Varnishes are calcium hydroxide in a resin base

Varnishes are used to insulate the pulp thermally

Varnishes are used beneath restorative resins to insulate the pulp against chemical irritants

Varnishes are base of ZnO engenol

#22. Which of the following possesses anti-cariogetic property?

ZnPO4 cement

Glass ionomer cement

Poly carboxylate cement

ZnO Eugenol cement

Calcium hydro-oxide cement

#23. What must be added to steel in order to render it ‘stainless’?

Chromium 12-30%

Carbon less than 1.2%

Chromium oxide 3-20%

Flouride 2-3%

#24. Hardness of which of the following abrasives is maximum?

Sand

Emery

Boron carbide

Silicone carbide

Potash.

#25. What is the maximum level of occupational exposure considered safe with regard to mercury vapors?

5 mg of mercury

50 mg of mercury

35 mg of mercury

25 mg of mercury

1 mg of mercury

#26. Which one of the following elastomeric rubber, resSi01tS is most likely to deform following in compression?

Addition silicone

Condensation silicone

Polyeth

Polysulfide

Siloxane

#27. The main resin constituent of polishable composite resin is:

Polymethymethacrylae

Polycarbonate

Cyanoacrylate

Urethane

Dimethacrylate

#28. Which of the following impression materials can be electroplated without risk of distortion?

Polysulphide

Condensation silicone

Addition silicone

Hydrocolloid impressions

Polyether

#29. In UV curing system, the activator employed is:

Benzoin methyl ether

Methylmethacrylate

Hydroquinone

Dibutylphthalate

Benzoic acid

#30. Regarding base metal alloys:

The casting shrinkage of base metal alloys is less than that of gold alloys.

Chromium added to base metal alloy acts as a solid solution hardner.

Carbide precipitation to a certain extent decreases strength of the alloys.

Manganese and silicone are added to base metal alloys to act as accelerator.

Cobalt act to provide flexibility to base metal alloy

#31. Creep value of which of the following is highest?

LOW copper amalgam alloy

Admix alloy

single composition alloys

Creep value of all the above mentioned alloys is same

High copper amalgam alloy

#32. What is the purpose of addition of orthoethoxy benzole acid to zinc oxide eugenol cement?

To improve compressive strength of the cement

To limit oral solubility of the cement

To render the cement light curable

To improve ease of manipulation of cement

To improve tensile strength of the cement

#33. Stiffness refers to

Resistance to elastic deformation

Degree of elastic deformation

Expandability on heating

Shrinkage on cooling

Expansion on cooling

#34. How soon after contamination by moisture does a zinc containing amalgam restoration start expanding?

24 hours

1-2 days

3-5 days

One week

Two week

#35. Regarding dental Amalgam:

It is a mixture of silver alloy and mercury

It is be composed of spherical tin and mercury

It is a mixture of irregular particles of silver and tin

Amalgamation process is formed during heating of silver & mercury

The process of mixing amalgam is called Amalgamation

#36. Which of the following is used for pickling of casting made with gypsum bonded investments?

100% hydrochloric acid

Sulphuric acid

Ultra sonic devices with 100% hydrochloric acid

Hydrogen per oxide

Aluminium oxide

#37. Cement not irritant to pulpal tissue is

Calcium hydroxide cement

Silicate cement

Copper cement

Glass ionomer cement

Resins cement

#38. Which of the following is best for ‘cermet’ cement:

Cermet cement is glass ionomer cement with porcelain ceramic fillers

Cermet cement is glass ionomer cement with silver amalgam alloy particles in it

Cermet cement is a mixture of glass ionomer and resin cements

Cermet cement is light curable glass ionomer cement

Cermet cement is self cure composite resin

#39. Gold based metal ceramic alloys are best cast Lg which of the following?

Gypsum investment

Phosphate bonded investment with carbon

Phosphate bonded investment without carbon

Silica bonded

Silica bonded investment with cashon

#40. In light cure system the wavelength of radiation is in excess of:

100 nm

200 nm

300 nm

400 nm

500 nm

#41. What are the consequences of prolonged heating of a dental casting investment?

Disintegration of the investment

Rough moulds of investment

Contamination of the alloys

Any of the above

Expansion of alloys

#42. Dicor is:

Ceramic material with unusual strength

Ceramic material with excellent esthetics

Ceramic material which is castable

New type of restorative resin with minimum porosity and excellent esthetics

Dicor is having composite resins

#43. With respect to acid etching:

It creates a microscopically rough enamel surface

The eTchant is usually 20% phosphoric acid

The eTchant is usually applied for one minute

Following etching the eTchant should be washed away with phosphoric acid.

It creates macroscopically rough enamel surface.

#44. Regarding dental implant materials?

Titanium substructure is coated with tricalcium phosphate to act as disinfectant.

Ceramics are used as implant materials because of their aesthetics.

Co-Cr alloys (63% with other metals is- often used due to their outstanding strength

Commercially pure titanium should not be used as it can cause corrosion in vivo.

Calcium hydroxyapetite crystals are bonded to titanium for better adhesion to bone

#45. The firing temperature of high fusing porcelain lies in the range of:

1600-1950oF

2000-3400oF

2350-2500°F

2500 – 3400°F

1000 - 1500°F

Dental Materials III

Results

#1. What is the function of feldspar during preparation of dental porcelain of a metal ceramic Crown?

#2. Which one of the following is the safest and most reliable method of regulating setting time of gypsum products?

#3. Which of the following cements bonds to tooth structure, has an anticariogenic effect, has a degree of translucency and does not irritate the pulp?

#4. Which of the following gases used for soldering purposes has the highest temperature?

#5. Setting expansion of casting investment is approximately:

#6. Cement extensively used for attachment of orthodontic brackets to teeth is.

#7. The stainless steel loses its resistance to corrosion if heated to a high temperature because:

#8. Fillers are added to composite resin to:

#9. What is trituration

#10. Regarding zinc phosphate cements:

#11. The cement which has antibacterial property is:

#12. Most common drawback of amalgam restoration is:

#13. Regarding Glass ionomers:

#14. KHN of enamel is:

#15. Regarding alginate impression material:

#16. Which of the following impression materials is elastic?

#17. Which part of an amalgam restoration has the highest mercury concentration?

#18. Activating compound for visible light curing system:

#19. The knoop hardness number of which one of the following materials is closest to that of dentin (KHN 65)?

#20. Contraction away from margins.

#21. Which of the following statements relates best regarding cavity varnish?

#22. Which of the following possesses anti-cariogetic property?

#23. What must be added to steel in order to render it ‘stainless’?

#24. Hardness of which of the following abrasives is maximum?

#25. What is the maximum level of occupational exposure considered safe with regard to mercury vapors?

#26. Which one of the following elastomeric rubber, resSi01tS is most likely to deform following in compression?

#27. The main resin constituent of polishable composite resin is:

#28. Which of the following impression materials can be electroplated without risk of distortion?

#29. In UV curing system, the activator employed is:

#30. Regarding base metal alloys:

#31. Creep value of which of the following is highest?

#32. What is the purpose of addition of orthoethoxy benzole acid to zinc oxide eugenol cement?

#33. Stiffness refers to

#34. How soon after contamination by moisture does a zinc containing amalgam restoration start expanding?

#35. Regarding dental Amalgam:

#36. Which of the following is used for pickling of casting made with gypsum bonded investments?

#37. Cement not irritant to pulpal tissue is

#38. Which of the following is best for ‘cermet’ cement:

#39. Gold based metal ceramic alloys are best cast Lg which of the following?

#40. In light cure system the wavelength of radiation is in excess of:

#41. What are the consequences of prolonged heating of a dental casting investment?

#42. Dicor is:

#43. With respect to acid etching:

#44. Regarding dental implant materials?

#45. The firing temperature of high fusing porcelain lies in the range of:

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