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WorksheetsDental materials(Cuban Guide)
Total questions: 70
Worksheet time: 36mins
1. "Bumps" on a study model are the result of:
a. voids in the impression.
b. inadequately mixing the alginate.
c. taking too long to pour the stone.
d. using too much water in the stone mix.
2. The best way to influence the setting time of alginate is to:
a. add borax.
b. add potassium sulfate.
c. alter the temperature of the water.
d. The setting time of alginate can't be manipulated.
3. The principle ingredient of reversible hydrocolloid is:
a. agar.
b. silicone.
c. sodium alginate.
d. potassium alginate.
4. The loss of solvent by a solute is called:
a. gelation.
b. syneresis.
c. imbibition.
d. None of the above.
5. When used as a base, zinc phosphate's greatest physical characteristic is its:
a. pH.
b. solubility.
c. adhesive quality.
d. compressive strength.
6. The liner which best stimulates the development of reparative dentin is:
a. oil of cloves.
b. copal varnish.
c. calcium hydroxide.
d. zinc-oxide eugenol.
7. The most frequent cause of sealant failure is:
a. oil contamination.
b. poor tooth selection.
c. inadequate curing light.
d. contamination by saliva.
8. A cement base is utilized on badly decayed teeth before the filling is placed
in order to insulate and protect the pulp.
a. Both the statement and reason are true.
b. Both the statement and reason are false.
c. The statement is true, but the reason is false.
d. The statement is false, but the reason is true.
9. To delay the setting time of gypsum:
a. the water must be decreased.
b. borax can be added to the mix.
c. the mix should be stirred vigorously.
d. potassium sulfate can be added to the mix.
10. When converting from a sol to a gel, a reversible hydrocolloid undergoes
what kind of reaction?
a. Gelation
b. Physical
c. Chemical
d. It doesn't undergo any reaction .
11. The setting time of gypsum could be shortened by:
a. excess1ve m1xmg.
b. mixing with less water.
c. adding potassium sulfate.
d. All of the above .
12. Which of the following could be used as a fmal polish for gold, ceramic,
amalgam, or composite restorations in the mouth?
a. Rouge
b. Pumice
c. Tin oxide
d. Prophy-jet
13. Heat can be minimized when polishing by these three methods:
a. using a light touch.
b. using water as a cooling agent or lubricant.
c. using intermittent bursts with the prophy cup.
d. using firm pressure and a coarse, commercially prepared pumice.
14. The setting expansion of a gypsum product can be reduced by:
a. using less water in the mix.
b. using more water in the mix.
c. using stone instead of plaster.
d. Both a and c .
15. A Class IV restoration:
a. includes all pits and fissures.
b. includes the incisive angle of an anterior tooth.
c. includes the proximal surface of a posterior tooth.
d. includes the gingival third of the facial or lingual surface.
16. A dental cement may be used as a base because it:
a. can protect the pulp.
b. has adequate compressive strength.
c. is a poor conductor of temperature extremes.
d. All of the above.
17. A newly placed silver amalgam restoration adjacent to a cast gold crown
might cause:
a. syneresis.
b. galvanism.
c. microleakage.
d. thermal expansion.
18. The difference between an inlay and an onlay is that:
a. There is no difference between an inlay and an onlay
b. an inlay is made of silver; an onlay is made of gold.
c. an inlay should not exceed one-half the intercuspal distance, while an
onlay covers the cusps.
d. an onlay should not exceed one-half the intercuspal distance, while an
inlay covers the cusps .
19. When bonding, the enamel is etched to:
a. increase the chemical retention by increasing the bonded surface area.
b. decrease the chemical retention by decreasing the bonded surface area.
c. increase the mechanical retention by increasing the bonded surface area.
d. decrease the mechanical retention by decreasing the bonded surface area
20. When making a study model of stone, instead of plaster, one should:
a. use less water.
b. use more water.
c. mix twice as long.
d. never make a study model of stone.
21. Amalgam restorations are polished to:
a. decrease the surface area.
b. minimize plaque accumulation.
c. make them more resistant to corrosion.
d. All of the above.
22. Composite fillers include:
a. glass.
b. quartz.
c. silicate.
d. All of the above.
23.choose 3. Three toothpaste components used to fight hypersensitivity include:
a. sodium citrate.
b. potassium nitrate.
c. aluminum sulfate.
d. strontium chloride.
24. An example of a rigid impression material would be:
a. plaster.
b. compound.
c. zinc oxide/eugenol.
d. All of the above.
25. Which of the following agents should not be used to clean a metal-based
partial denture?
a. Bleach
b. Toothpaste
c. Mouthwash
d. Soap and warm water
26. How much time should elapse before a stone cast is removed from an
alginate impression?
a. 5 - 10 minutes
b. 15-25 minutes
c. 30-60 minutes
d. At least 90 minutes
27. The most effective way to insulate the pulp of a tooth is to:
a. use a liner.
b. use a base.
c. restore it with a cast gold crown.
d. restore it with a chrome-steel crown.
28. Zinc phosphate cement is left in the deepest portion of a tooth preparation
primarily to:
a. induce secondary dentin formation.
b. provide thermal insulation for the pulp.
c. improve the retention of the amalgam filling.
d. All of the above.
29. Which of the following is a disadvantage of an impression obtained with
hydrocolloid?
a. High gel strength
b. High melting point
c. Excessive viscosity
d. Lack of dimensional stability
30. Two ways to prevent the creation of a Class II overhang include:
a. use a base.
b. only use amalgam.
c. place a wedge interproximally.
d. use a properly shaped and placed matrix band .
31. The easiest way to detect an amalgam overhang is with:
a. an explorer.
b. a gold knife.
c. a polishing disc.
d. a high speed bur.
32. Recurrent root decay is generally classified by G. V. Black as:
a. class II.
b. class V.
c. class IV.
d. class 11.1
33. Heat generated while polishing an alloy would most likely damage:
a. the cementum.
b. the odontoblasts.
c. the enamel prisms.
d. the periodontal ligament.
34. The cement which has the greatest chemical affinity for enamel is:
a. resm.
b. glass ionomer.
c. zinc phosphate.
d. polycarboxylate.
35. Seen in a radiograph, a composite restoration might appear:
a. radiopaque.
b. radiolucent.
c. less radiopaque than an alloy.
d. All of the above
36. If high compressive strength was the single most important requirement in
selecting a restorative material, the material of choice would be:
a. amalgam.
b. composite.
c. glass ionomer.
d. a cast metal restoration.
3 7. The material of choice for a Class VI restoration would be:
a. amalgam .
b. composite.
c. glass ionomer.
d. a cast metal restoration.
38. If left in water, an alginate impression undergoes what process?
a. Syneresis
b. Imbibition
c. Hysteresis
d. Both a and c.
39. The gypsum product with the least compressive strength is:
a. stone.
b. plaster.
c. improved stone.
d. None of the above.
40. Intraorally, a clinician may polish gold with tin oxide. Extraorally, a
clinician or laboratory technician may polish gold with rouge.
a. Both statements are true.
b. Both statements are false.
c. Only the first statement is true.
d. Only the second statement is true.
41. A cantilevered bridge can be easily identified radiographically because:
a. porcelain is radiopaque.
b. it always has an open contact.
c. it is always made of cast gold.
d. it is supported on only one side.
42. A benefit of light-cured composites over self-cured composites is:
a. that they require no mixing
b. that they have reduced porosity
c. Both a and b.
d. None of the above.
43. Polycarboxylate cements contain which acid?
a. Muriatic
b. Phosphoric
c. Polyacrylic
d. Polycarboxylate cements contain no acid.
44. Fluffmg (aerating) alginate before using it:
a. prevents syneresis.
b. accelerates the set.
c. prevents imbibition.
d. compensates for settling or particle compaction due to storage.
45. Zinc phosphate cement helps keep a crown in place by its:
a. ability to release fluoride.
b. high chemical affinity for dentin.
c. ability to generate heat when mixed.
d. mechanical interlock between crown and tooth.
46. An improperly carved occlusal amalgam restoration may result in:
a. fracture of the filling or the tooth.
b. tenderness of the tooth to percussion.
c. tooth hypersensitivity to temperature changes.
d. Any of the above.
47. The best agent for cleaning instruments used in mixing ZOE cement is:
a. water.
b. eucalyptol.
c. orange solvent.
d. benzalconium chloride.
48. Three ways to ensure the best results in mixing a gypsum product include:
a. weigh the necessary gypsum.
b. measure the proper volume of water.
c. mix and vibrate for a minimum of ten minutes.
d. vibrate the mixed gypsum to release trapped air.
49. Which of the following is most likely to cause delayed expansion in an
amalgam restoration containing zinc?
a. Heavy condensation
b. Excess mercury in the mix
c. Overtrituration of the amalgam
d. Contamination by moisture during placement
50. The setting rate of an irreversible hydrocolloid may be slowed safely and
effectively by:
a. increasing the spatulation time.
b. decreasing the ratio of water to powder.
c. decreasing the temperature of the mixing water.
d. increasing the temperature of the mixing water.
51. After a wax pattern is formed, the resulting casting will be more accurate if
the pattern is:
a. invested immediately.
b. kept in a refrigerator.
c. kept at room temperature.
d. any of the above answers.
52. A force exerted to stretch a material to the point of fracture indicates its:
a. ductility.
b. malleability.
c. tensile strength.
d. compressive strength.
53. A dental amalgam alloy contains three of the following elements:
a. tin.
b. silver.
c. copper.
d. magnesium.
54. Dental alloys become amalgam when mixed with:
a. lead.
b. silver.
c. mercury.
d. magnesium.
55. The volumetric weight of one cubic millimeter of water is equal to one:
a. gram.
b. atom.
c. pound.
d. kilogram.
56. The Brinnell and Knoop tests are used in determining:
a. ductility.
b. hardness.
c. elasticity.
d. malleability.
57. An impression material should be mixed:
a. for ten seconds.
b. for thirty seconds.
c. for twenty seconds.
d. according to the manufacturer's directions.
58. Air incorporated into a gypsum mix results in:
a. additional strength.
b. a smoother surface.
c. surface voids and irregularities.
d. None of the above.
59. If saliva contaminates the tooth during the placement of a sealant, one
should:
a. reappoint the patient.
b. have a dentist fill the tooth.
c. check with the clinic supervisor.
d. isolate with fresh cotton products or dam, andre-etch the tooth.
60. When gypsum begins to set, it:
a. changes color.
b. expands slightly.
c. contracts slightly.
d. remains dimensionally stable.
61. Alginate is also known as:
a. polyvinyl siloxane.
b. reversible hydrocolloid.
c. irreversible hydrocolloid.
d. a hydrophobic impression material.
62. The defming characteristic of a noble metal is that:
a. it is expensive.
b. it is resistant to corrosion.
c. it is used to make jewelry.
d. it is publicly traded as a commodity.
63. The gypsum product which requires the most water to mix is:
a. stone.
b. plaster.
c. die stone.
d. investment.
64. Glutaraldehyde fumes are:
a. toxic.
b. strong.
c. offensive.
d. All of the above.
65. An interproximal composite on an anterior tooth is classified by G. V.
Black as a:
a. Class I restoration
b. Class II restoration
c. Class III restoration
d. Class IV restoration
66. The main ingredient in a sealant material is:
a. glass ionomer.
b. zinc phosphate.
c. BIS-GMA resin.
d. polyacrylic acid.
67. Pyrophosphates are added to commercial toothpaste preparations to prevent
tartar accumulation. Triclosan is sometimes added as an antimicrobial agent.
a. Both statements are true.
b. Both statements are false.
c. Only the first statement is true.
d. Only the second statement is true.
68. An amalgam might be used to restore a lingual, Class V cavity because:
a. it is unlikely to be seen.
b. it is an effective restorative material.
c. it is easily adapted to lingual pits and irregular surfaces.
d. All of the above.
69. If a material is considered highly ductile, it:
a. is likely to be quite brittle.
b. may bend without breaking.
c. will return to its original shape after having been stretched.
d. None of the above.
70. The contraction of a gel due to a loss of solvent is called:
a. synerests.
b. adhesion.
c. imbibition.
d. malleability.
