Dental Materials Foundations And Applications 11th Edition by Powers – Test Bank

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INSTANT DOWNLOAD COMPLETE TEST BANK WITH ANSWERS

 

Dental Materials Foundations And Applications 11th Edition by Powers – Test Bank

 

Sample  Questions

 

 

Chapter 02: Properties of Materials

Powers: Dental Materials, 11th Edition

 

MULTIPLE CHOICE

 

  1. For which of the following materials do dimensional changes occur during setting as a result of a chemical reaction?
a. Elastomeric impression materials
b. Gold restorations
c. Wax patterns
d. A and C
e. B and C

 

 

ANS:  A

 

  Feedback
A Dimensional changes occur during setting as a result of a chemical reaction with elastomeric impression materials. Resin composite materials also set as a result of a chemical reaction and undergo shrinkage.
B Gold restorations undergo dimensional changes from cooling during fabrication.
C Wax patterns undergo dimensional changes from cooling during fabrication.
D A and C are incorrect answers.
E B is an incorrect answer, and C is an incorrect answer.

 

 

DIF:    Comprehension                              REF:   p.  15             OBJ:   1

TOP:   CDA, GC, III. Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. How is the percentage of dimensional change measured?
a. An original length or volume
b. The final length or volume
c. The compressive strength
d. The tensile strength
e. The shear strength

 

 

ANS:  A

 

  Feedback
A The dimensional change usually is expressed as a percentage of an original length or volume, not the final length or volume.
B The dimensional change usually is expressed as a percentage of an original length or volume, not the final length or volume.
C Compressive strength is a measure of stress that may result when force is applied to a material.
D Tensile strength is a measure of stress that may result when force is applied to a material.
E Shear strength is a measure of stress that may result when force is applied to a material.

 

 

DIF:    Knowledge     REF:   p.  15             OBJ:   1

TOP:   CDA, GC, III. Chairside Dental Materials (Preparation, Manipulation and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. The volumetric dimensional change is equal to _____ times the linear dimensional change.
a. two
b. three
c. four
d. six

 

 

ANS:  B

 

  Feedback
A Two is an incorrect answer.
B The volumetric dimensional change is equal to three times the linear dimensional change. Volume is described as length times width times depth (or height).
C Four is an incorrect answer.
D Six is an incorrect answer.

 

 

DIF:    Knowledge     REF:   p.  15             OBJ:   1

TOP:   CDA, GC, III. Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Because the thermal expansion of a restorative material usually does not match that of the tooth structure, a differential expansion or contraction occurs that may result in leakage of oral fluids between the restoration and tooth.
a. Statement 1 is correct; statement 2 is correct.
b. Statement 1 is correct; statement 2 is incorrect.
c. Statement 1 is incorrect; statement 2 is correct.
d. Statement 1 is incorrect; statement 2 is incorrect.

 

 

ANS:  A

 

  Feedback
A Statement 1 is correct; statement 2 is correct.
B Statement 1 is correct; statement 2 is correct.
C Statement 1 is correct; statement 2 is correct.
D Statement 1 is correct; statement 2 is correct.

 

 

DIF:    Comprehension                              REF:   p.  15             OBJ:   2

TOP:   CDA, GC, III. Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. A new addition silicone impression material is tested for linear dimensional change upon setting. The result of –0.34% indicates that _______________ took place within 24 hours after setting.
a. linear expansion
b. linear shrinkage
c. thermal expansion
d. thermal shrinkage

 

 

ANS:  B

 

  Feedback
A Linear thermal expansion is expressed as a coefficient of thermal expansion.
B The result is a negative number, which indicates shrinkage took place.
C Thermal expansion is measured by determination of the difference in the length of a specimen at two temperatures.
D Shrinkage is measured by determination of the difference in the length of a specimen at two temperatures.

 

 

DIF:    Knowledge     REF:   p.  15             OBJ:   1

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. The thermal coefficient of expansion _____ uniform throughout the entire temperature range and is usually _________ for liquids than solids.
a. is; lower
b. is; higher
c. is not; lower
d. is not; higher

 

 

ANS:  D

 

  Feedback
A The thermal coefficient of expansion for a solid generally increases at some point as the temperature is increased.
B The thermal coefficient of expansion for a solid generally increases at some point as the temperature is increased.
C The thermal coefficient of expansion for a solid generally increases at some point as the temperature is increased.
D The thermal coefficient of expansion is not uniform throughout the entire temperature range and is usually higher for liquids than solids.

 

 

DIF:    Comprehension                              REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following restorative materials has a linear thermal coefficient of expansion that is lower than that of human teeth?
a. Ceramics
b. Composites
c. Dental amalgam
d. Unfilled acrylics and sealants

 

 

ANS:  A

 

  Feedback
A Ceramics have a linear thermal coefficient of expansion of 14. Teeth have a linear thermal coefficient of expansion of 15.
B The linear thermal coefficient of expansion of composites is 68.
C The linear thermal coefficient of expansion of dental amalgam is 28.
D The linear thermal coefficient of expansion of unfilled acrylics and sealants is 100.

 

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following dental restorative materials has a linear coefficient of thermal expansion closest to teeth?
a. Unfilled acrylics and sealants
b. Glass ionomer base
c. Dental amalgam
d. Composites
e. Gold alloys

 

 

ANS:  A

 

  Feedback
A Unfilled acrylics and sealants have a linear coefficient of thermal expansion of 70-100.
B Glass ionomer base has a linear coefficient of thermal expansion of 10-11.
C Dental amalgam has a linear coefficient of thermal expansion of 22-28.
D Composites have a linear coefficient of thermal expansion of 25-68.
E Gold alloys have a linear coefficient of thermal expansion that is closest to teeth.

 

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. What occurs as the result of a discrepancy between the linear thermal coefficient of expansion between teeth and the restorative material if there is no bonding?
a. Stress
b. Strain
c. Percolation
d. Yield strength
e. Elastic modulus

 

 

ANS:  D

 

  Feedback
A If the restoration is bonded, then stress occurs at the interface of the tooth and restoration.
B Strain occurs as result of the change in length or deformation by unit.
C Percolation occurs as the result of a discrepancy between the linear thermal coefficient of expansion between teeth and the restorative material. It is thought to be undesirable due to possible irritation to the dental pulp and recurrent decay.
D Yield strength is affected by stress at some arbitrary value.
E Elastic modulus equals the ratio of stress to strain.

 

 

DIF:    Knowledge     REF:   p.  20             OBJ:   6

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Percolation is thought to decrease with time following insertion of which of the following dental restorative materials?
a. Filled resin composite
b. Unfilled acrylic resin
c. Dental amalgam
d. Cast gold
e. Ceramic

 

 

ANS:  D

 

  Feedback
A Filled resin composite is restoration that is either bonded or cemented into place. Percolation related to these restorations would place stress at the interface, which over time would lead to failure of the bond.
B Unfilled acrylic resin is restoration that is either bonded or cemented into place. Percolation related to these restorations would place stress at the interface, which over time would lead to failure of the bond.
C Percolation is thought to decrease with time with dental amalgam, presumably as a result of the space being filled with corrosion products from the amalgam.
D Cast gold is restoration that is either bonded or cemented into place. Percolation related to these restorations would place stress at the interface, which over time would lead to failure of the bond.
E Ceramic is restoration that is either bonded or cemented into place. Percolation related to these restorations would place stress at the interface, which over time would lead to failure of the bond.

 

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. What is used as a measurement of heat transfer?
a. Linear coefficient of thermal expansion
b. Thermal conductivity
c. Galvanism
d. Absorption
e. Adsorption

 

 

ANS:  B

 

  Feedback
A Linear coefficient of thermal expansion is determined by the length of a specimen at two temperatures.
B Thermal conductivity is used as a measure of heat transferred.
C Galvanism is the generation of an electric current a patient can feel.
D Absorption refers to uptake of liquid.
E Adsorption refers to concentration of molecules at the surface of a solid or liquid.

 

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following dental restorative materials has the greatest thermal conductivity?
a. Resin composites
b. Unfilled acrylics
c. Dental amalgam
d. Gold alloys
e. Ceramic

 

 

ANS:  D

 

  Feedback
A Resin composites have thermal conductivities comparable to tooth structure.
B Unfilled acrylics have lower thermal conductivity than enamel.
C The thermal conductivity of dental amalgam is substantially lower than gold.
D Gold alloys have the greatest thermal conductivity.
E Ceramic has thermal conductivity comparable to tooth structure.

 

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following dental materials has a thermal conductivity that is most similar to tooth structure?
a. Composites
b. Gold alloys
c. Dental amalgam
d. Zinc phosphate cement
e. Zinc oxide–eugenol cement

 

 

ANS:  B

 

  Feedback
A Composites have thermal conductivity most similar to tooth structure.
B Gold alloys have thermal conductivity higher than tooth structure.
C Dental amalgam has some thermal conductivity but not at a level similar to tooth structure.
D Zinc phosphate cement is a poor conductor of temperature and is used for insulating bases.
E Zinc oxide–eugenol cement is a poor conductor of temperature and is used for insulating bases.

 

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Why are cavity varnishes and liners ineffective as thermal insulators?
a. Used in thin layers
b. High thermal conductivity
c. Low coefficient of thermal expansion
d. High coefficient of thermal expansion

 

 

ANS:  A

 

  Feedback
A Cavity varnishes and liners have low thermal conductivities but are used in layers so thin that they are ineffective as thermal insulators.
B Varnishes and liners have low thermal conductivity.
C Low coefficient of thermal expansion is a measurement of how much a material expands.
D High coefficient of thermal expansion is a measurement of how much a material expands.

 

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following is an electrical property of interest in the mouth?
a. Coefficient of thermal expansion
b. Elastic modulus
c. Percolation
d. Galvanism
e. Ductility

 

 

ANS:  D

 

  Feedback
A Coefficient of thermal expansion measures how much a material expands.
B Elastic modulus is equal to the ratio of stress to strain in the liner portion of the stress-strain curve.
C Percolation occurs as the result of a discrepancy between the linear thermal coefficient of expansion between teeth and the restorative material.
D Galvanism is an electrical property. Galvanism results from the presence of dissimilar metals in the mouth. Metals placed in an electrolyte have various inherent tendencies to go into solution.
E Ductility is the percent of elongation.

 

 

DIF:    Knowledge     REF:   p.  17             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Given a schematic sketch of two opposing teeth, one with a temporary aluminum alloy crown and the other with a gold crown, which one would be the electrolyte?
a. Saliva
b. Gold crown
c. Difference in electrical potential
d. Temporary aluminum alloy crown

 

 

ANS:  A

 

  Feedback
A The saliva functions as the electrolyte.
B Gold crown does not go into solution.
C The difference in electrical potential in this case would be 2.69 volts. The patient experiences pain and a metallic taste.
D Temporary aluminum alloy crown has a tendency to go into solution.

 

 

DIF:    Knowledge     REF:   p.  17             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. What refers to the uptake of liquid by a bulk solid?
a. Absorption
b. Adsorption
c. Hydrophilic
d. Hydrophobic

 

 

ANS:  A

 

  Feedback
A Absorption refers to the uptake of liquid by a bulk solid.
B Adsorption indicates concentration of molecules at the surface of a solid or liquid.
C Hydrophilic surface is readily wetted if the solution is water.
D Hydrophobic surface is resistant to wetting if the solution is water.

 

 

DIF:    Knowledge     REF:   p.  17             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following terms indicates concentration of molecules at the surface of a solid or liquid?
a. Corrosion
b. Adsorption
c. Absorption
d. Hydrophilic

 

 

ANS:  B

 

  Feedback
A Corrosion is the dissolution of metals in the mouth.
B Adsorption indicates concentration of molecules at the surface of a solid or liquid.
C Absorption is the uptake of liquid by a bulk solid.
D Hydrophilic surface is readily wetted if the solution is water.

 

 

DIF:    Knowledge     REF:   p.  17             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. With regard to wettability and water, what does a low contact angle indicate?
a. The material is hydrophilic.
b. The material is hydrophobic.
c. The contact angle is greater than 90°.
d. Both A and C are correct.
e. Both B and C are correct.

 

 

ANS:  A

 

  Feedback
A A low contact angle indicates the material is hydrophilic.
B If the contact angle is greater than 90°, poor wetting occurs.
C The material is considered hydrophobic if the liquid is water.
D A is correct, and C is incorrect.
E B and C are incorrect.

 

 

DIF:    Comprehension                              REF:   p.  18             OBJ:   4

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following choices encourage good wetting?
a. Low-energy solid
b. High-energy solid
c. High-energy liquid
d. A and C are correct.
e. B and C are correct.

 

 

ANS:  A

 

  Feedback
A Liquids bead up on low-energy solids.
B High-energy solids and low-energy liquids encourage good wetting.
C High-energy liquids can be made more wettable by adding a wetting agent.
D A is correct, and C is incorrect.
E B and C are incorrect.

 

 

DIF:    Comprehension                              REF:   p.  18             OBJ:   4

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. On which teeth are the greatest biting forces located?
a. Molars
b. Canines
c. Incisors
d. Premolars

 

 

ANS:  A

 

  Feedback
A The greatest biting forces are on molars.
B Canines’ maximum biting forces decrease from the molar to the incisor region.
C Premolars’ maximum biting forces decrease from the molar to the incisor region.
D Incisors’ maximum biting forces decrease from the molar to the incisor region.

 

 

DIF:    Knowledge     REF:   p.  18             OBJ:   5

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Patients with dentures can apply about ____% of the force of those with normal dentition.
a. 10
b. 19
c. 50
d. 90
e. 150

 

 

ANS:  B

 

  Feedback
A Patients with dentures can apply about 19% of the force of those with normal dentition.
B Patients with dentures can apply about 19% of the force of those with normal dentition.
C Patients with dentures can apply about 19% of the force of those with normal dentition.
D Patients with dentures can apply about 19% of the force of those with normal dentition.
E Patients with dentures can apply about 19% of the force of those with normal dentition.

 

 

DIF:    Knowledge     REF:   p.  18             OBJ:   5

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. What is the ratio of the force to the area called?
a. Stress
b. Strain
c. Tensile strength
d. Elastic modulus

 

 

ANS:  A

 

  Feedback
A The ratio of the force to the area is called stress.
B Strain changes in length per unit of a material produced by stress.
C Tensile strength results when a material fractures from tensile stress.
D Elastic modulus is equal to the ratio of the stress to the strain.

 

 

DIF:    Knowledge     REF:   p.  18             OBJ:   5

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. For a given force, the _______ the area over which it is applied, the ________ the value of the stress.
a. smaller; smaller
b. smaller; larger
c. larger; larger
d. A and C
e. B and C

 

 

ANS:  B

 

  Feedback
A The smaller the area over which force is applied, the larger the value of stress.
B The smaller the area over which force is applied, the larger the value of stress.
C The smaller the area over which force is applied, the larger the value of stress.
D The smaller the area over which force is applied, the larger the value of stress.
E The smaller the area over which force is applied, the larger the value of stress.

 

 

DIF:    Comprehension                              REF:   p.  18             OBJ:   5

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following statements is true of the proportional limit?
a. Below the proportional limit a material is plastic, and above the proportional limit it is elastic.
b. Below the proportional limit a material is elastic, and above the proportional limit it is plastic.
c. A material is elastic both below and above the proportional limit.
d. A material is plastic both below and above the proportional limit.

 

 

ANS:  B

 

  Feedback
A A restoration can be classified as a clinical failure if deformation occurs beyond set limits.
B Below the proportional limit a material is elastic, and above the proportional limit it is plastic.
C A restoration can be classified as a clinical failure if deformation occurs beyond set limits.
D A restoration can be classified as a clinical failure if deformation occurs beyond set limits.

 

 

DIF:    Knowledge     REF:   p.  20             OBJ:   6

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following statements is true of the tensile and compressive strengths of a material?
a. They may be significantly different.
b. Brittle materials are stronger in tension than in compression.
c. Brittle materials have small differences in tensile and compressive strength.
d. A, B, and C are true.
e. A and C are true.

 

 

ANS:  A

 

  Feedback
A The tensile and compressive strength of a material may be significantly different.
B Brittle materials such as human enamel, amalgam, and composites have large differences and are stronger in compression than in tension.
C Brittle materials such as human enamel, amalgam, and composites have large differences and are stronger in compression than in tension.
D Brittle materials such as human enamel, amalgam, and composites have large differences and are stronger in compression than in tension.
E Brittle materials such as human enamel, amalgam, and composites have large differences and are stronger in compression than in tension.

 

 

DIF:    Comprehension                              REF:   p.  20             OBJ:   6

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. “Measures the energy required to fracture a material” is the definition of which term?
a. Ductility
b. Resilience
c. Toughness
d. Malleability

 

 

ANS:  C

 

  Feedback
A Ductility is the percent of elongation.
B Resilience is the energy required to deform a material.
C The energy required to fracture a material is a measure of its toughness.
D Malleability is the percent of compression.

 

 

DIF:    Analysis         REF:   p.  21             OBJ:   7

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following statements is true of the measure of Knoop hardness?
a. It is obtained by measurement of the short diagonal of an indentation from a diamond indenter.
b. Enamel has a lower Knoop hardness value than dentin and cementum.
c. Hardness is directly related to yield strength and wear resistance.
d. The larger the indentation, the smaller the value.

 

 

ANS:  D

 

  Feedback
A In general, no direct relationship exists between hardness and yield strength and wear resistance.
B Enamel has a higher Knoop hardness value than dentin and cementum.
C In general, no direct relationship exists between hardness and yield strength and wear resistance.
D The larger the indentation of the measurement of the long diagonal from a diamond indenter, the smaller the Knoop hardness value.

 

 

DIF:    Analysis         REF:   p.  21             OBJ:   8

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Analysis of the strain–time curve indicates that the ________ the time and the _____ force applied to the impression material, the lower the permanent strain and the more accurate the impression.
a. shorter; less
b. longer; less
c. shorter; more
d. longer; more

 

 

ANS:  A

 

  Feedback
A The shorter the time and the less force applied to the impression material, the lower the permanent strain and the more accurate the impression.
B Longer time will result in more force to the material.
C Shorter time will result in less force to the material.
D Longer time will result in more force to the material and compromise the accuracy of the impression.

 

 

DIF:    Analysis         REF:   p.  22             OBJ:   9

TOP:   CDA, GC, V. A.1b. Patient Education and Oral Health Management

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Dimensional change may occur during setting as a result of which factor?
a. Volumetric change
b. Chemical reaction
c. Cooling
d. All of the above
e. B and C are correct.

 

 

ANS:  E

 

  Feedback
A Volumetric change is more difficult to measure.
B B and C are correct answers.
C B and C are correct answers.
D B and C are correct answers.
E Dimensional changes may occur during setting as a result of a chemical reaction, such as with elastomeric impression materials or resin composite restorative materials, or from the cooling of wax patterns or gold restorations during fabrication.

 

 

DIF:    Comprehension                              REF:   p.  15             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Expansion and contraction rates between dental materials and tooth structure caused by temperature change vary. Gaps at the margins allow fluids to enter the space. What is this known as?
a. Coefficient of thermal expansion
b. Thermal conductivity
c. Dimensional change
d. Percolation

 

 

ANS:  D

 

  Feedback
A Coefficient of thermal expansion is expressed as the linear difference of a specimen at two temperatures.
B Thermal conductivity is used to measure heat transference.
C Dimensional change is expressed as a percent of the original length.
D Small gaps result at the junction between the two materials. Oral fluids can penetrate this space. When the temperature returns to normal, this fluid is forced out of the space. This phenomenon is called percolation.

 

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Of the following materials, which has the closest coefficient of expansion to tooth structure?
a. Ceramic
b. Amalgam
c. Filled polymers
d. Composite resins

 

 

ANS:  A

 

  Feedback
A Ceramic is the closest, being one half to one third, and gold alloys being approximately the same as for human teeth.
B Values for amalgam and composites are about two to five times those of human teeth.
C Values for unfilled polymers, however, are five to seven times those of teeth.
D Values for amalgam and composites are about two to five times those of human teeth.

 

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following materials has the highest rating related to thermal conductivity?
a. Glass ionomer
b. Gold alloy
c. Enamel
d. Dentin

 

 

ANS:  B

 

  Feedback
A Glass ionomer cement bases closely replace lost tooth structure with respect to thermal conductivity.
B Human enamel and dentin are poor thermal conductors compared with gold alloys and dental amalgam, although amalgam is substantially lower than gold.
C Human enamel and dentin are poor thermal conductors.
D Human enamel and dentin are poor thermal conductors.

 

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. What causes corrosion?
a. Contact of two dissimilar metals in the mouth
b. Poor oral hygiene around restorations
c. Acidic food and drink
d. A and C are correct.

 

 

ANS:  D

 

  Feedback
A A and C are correct.
B Poor oral hygiene around restorations may result in recurrent caries formation.
C Corrosion also may result from chemical attack of metals by components in food or saliva.
D Corrosion also can result from this same condition when adjacent restorations are of dissimilar metals. Corrosion may also be a factor due to chemical attacks for food and saliva in the mouth.

 

 

DIF:    Knowledge     REF:   p.  17             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which term refers to the cause of a metallic taste in the mouth?
a. Corrosion
b. Galvanism
c. Percolation
d. Contamination

 

 

ANS:  B

 

  Feedback
A Corrosion is a result of the same condition. As a result of the galvanic action, material goes into solution, and roughness and pitting occur.
B When the two restorations touch, current flows because the potential difference is 2.69 volts, and the patient experiences pain and frequently complains of a metallic taste.
C Small gaps result at the junction between the two materials. Oral fluids can penetrate this space. When the temperature returns to normal, this fluid is forced out of the space. This phenomenon is called percolation.
D Corrosion may occur if a gold alloy is contaminated with a metal such as iron during handling in the dental laboratory.

 

 

DIF:    Knowledge     REF:   p.  17             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. What is a material called if a liquid presents a contact angle of wettability greater than 90°?
a. Viscous
b. Thixotropic
c. Hydrophilic
d. Hydrophobic

 

 

ANS:  C

 

  Feedback
A Viscosity is related to the thickness of a material and may be affected by temperature.
B Thixotropic materials require force to be distributed.
C Hydrophilic materials flow readily.
D If a contact angle is greater than 90°, poor wetting occurs (hydrophobic if the liquid is water).

 

 

DIF:    Knowledge     REF:   p.  18             OBJ:   4

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which of the following is not a form of stress?
a. Compressive
b. Flexure
c. Strain
d. Shear

 

 

ANS:  C

 

  Feedback
A Compressive is a type of stress that may result when a force is applied to a material.
B Flexure is a type of stress that may result when a force is applied to a material.
C Strain is the change in length per unit length of a material produced by stress.
D Shear is a type of stress that may result when a force is applied to a material.

 

 

DIF:    Knowledge     REF:   p.  19             OBJ:   5

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Which term refers to the change in the length or deformation of a material when subjected to force?
a. Flexure
b. Tensile
c. Strain
d. Shear

 

 

ANS:  C

 

  Feedback
A Flexure is a type of stress.
B Tensile is a type of stress.
C Strain is the change in length or deformation per unit length when a material is subjected to a force.
D Shear is a type of stress.

 

 

DIF:    Knowledge     REF:   p.  19             OBJ:   5

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. When a material reaches its ______________, deformation of a material becomes permanent.
a. stress-strain curve
b. ultimate strength
c. elastic modulus
d. yield strength

 

 

ANS:  D

 

  Feedback
A Stress–strain curve is the application of various forces to determine the corresponding values of stress and strain.
B Ultimate strength is the stress at which fracture occurs.
C Elastic modulus is equal to the ratio of the stress to the strain.
D Yield strength is the measure of the stress allowed before permanent deformation.

 

 

DIF:    Knowledge     REF:   p.  20             OBJ:   6

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. How is the hardness of a dental material reported?
a. Knoop hardness
b. Nano-indentation
c. Diamond indenter
d. Dynamic properties

 

 

ANS:  A

 

  Feedback
A The hardness of dental materials generally is reported in Knoop hardness.
B Nano-indentation measures small indentations from small loads.
C Diamond indenter creates a length of the long diagonal of an indentation.
D Dynamic properties occur at extremely high rates of loading such as an impact.

 

 

DIF:    Knowledge     REF:   p.  21             OBJ:   8

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. What is the energy it takes to deform a material called?
a. Relationship
b. Resistance
c. Resilience
d. Rebound

 

 

ANS:  C

 

  Feedback
A Relationship is a distractor.
B Resistance is a material’s ability to stay the same.
C The energy required to deform a material permanently is a criterion of its resilience.
D Rebound is a material’s ability to return to its original form.

 

 

DIF:    Knowledge     REF:   p.  21             OBJ:   7

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. What is the energy necessary to fracture called?
a. Yield strength
b. Toughness
c. Stress
d. Strain

 

 

ANS:  B

 

  Feedback
A The yield strength is the stress at some arbitrarily selected value of permanent strain, such as 0.001, and thus is always slightly higher than the proportional limit.
B The energy necessary to fracture a material is a measure of its toughness.
C When force is distributed over an area, the ratio of the force to the area is called the stress.
D Strain is the change in length per unit length of a material produced by stress.

 

 

DIF:    Knowledge     REF:   p.  21             OBJ:   7

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

SHORT ANSWER

 

  1. Detail the significance of thermal dimensional change.

 

ANS:

Restorative dental materials are subjected to temperature changes in the mouth. These changes result in dimensional changes in the materials and to the neighboring tooth structure. Because the thermal expansion of the restorative material usually does not match that of the tooth structure, a differential expansion occurs that may result in leakage of oral fluids between the restoration and the tooth.

 

DIF:    Comprehension                              REF:   p.  15             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Compare and contrast the terms absorption and adsorption.

 

ANS:

Absorption refers to the uptake of liquid by the bulk solid. For example, the equilibrium absorption of water by acrylic polymers is in the range of 2%. Adsorption indicates concentration of molecules at the surface of a solid or liquid.

 

DIF:    Analysis         REF:   p.  17             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Explain the difference between ductility and malleability.

 

ANS:

The percents of elongation and compression are important properties in that they are measures of ductility and malleability, respectively. These two properties are indications of the amount of plastic strain or deformation that can occur before the material fractures and, as such, indicate the brittleness of the material.

 

DIF:    Comprehension                              REF:   p.  21             OBJ:   6

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. What is the purpose of using dental cements as bases within a cavity preparation?

 

ANS:

The reason for using cements as thermal insulating bases in deep cavity preparations is that although dentin is a poor thermal conductor, a thin layer of it does not provide enough thermal insulation for the pulp unless a cement base is used under the metal restoration.

 

DIF:    Knowledge     REF:   p.  16             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Compare and contrast the processes of tarnish and corrosion.

 

ANS:

Corrosion is the dissolution of metals in the mouth. Corrosion also can result from this same condition when adjacent restorations are of dissimilar metals. As a result of the galvanic action, material goes into solution, and roughness and pitting occur. Corrosion may also be a reaction to the acids formed by food remnants combining with saliva. Tarnish is a surface reaction of metals in the mouth from components in saliva or foods. Corrosion is destructive whereas tarnish is just unsightly.

 

DIF:    Analysis         REF:   p.  17             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application)

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

Chapter 04: Direct Esthetic Restorative Materials

Powers: Dental Materials, 11th Edition

 

MULTIPLE CHOICE

 

  1. Which of the following is the most popular direct esthetic dental restorative material?
a. Composite
b. Compomer
c. Glass ionomer
d. Hybrid ionomer

 

 

ANS:  A

 

  Feedback
A Composite is the most popular direct esthetic restorative material.
B Compomers have distinct advantages as direct esthetic restorations. However, they are weaker than composite resins and should be used under specific parameters.
C Glass ionomers have distinct advantages as direct esthetic restorations. However, they are weaker than composite resins and should be used under specific parameters.
D Hybrid ionomers have distinct advantages as direct esthetic restorations. However, they are weaker than composite resins and should be used under specific parameters.

 

 

DIF:    Knowledge     REF:   p.  42             OBJ:   1

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following direct esthetic restorative materials releases the least fluoride?
a. Hybrid ionomer
b. Glass ionomer
c. Compomer
d. Composite

 

 

ANS:  D

 

  Feedback
A Hybrid ionomer contains a fluoride ion that leaches into the tooth structure for added protection.
B Glass ionomer contains a fluoride ion that leaches into the tooth structure for added protection.
C Compomer contains a fluoride ion that leaches into the tooth structure for added protection.
D Composite releases the least fluoride.

 

 

DIF:    Knowledge     REF:   p.  42             OBJ:   2

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following is not a direct esthetic restorative material?
a. Ceramic
b. Composite
c. Compomer
d. Glass ionomer

 

 

ANS:  A

 

  Feedback
A Currently, four types of materials are being used as direct esthetic dental restorations: composites, compomers, resin-modified glass ionomers, and glass ionomers. Ceramic restorations are indirect; fabricated outside of the mouth.
B Composite is used in direct placement esthetic restorations. Ceramic is used for indirect esthetic restorations.
C Compomer is used in direct placement esthetic restorations. Ceramic is used for indirect esthetic restorations.
D Glass ionomer is used in direct placement esthetic restorations. Ceramic is used for indirect esthetic restorations.

 

 

DIF:    Knowledge     REF:   p.  42             OBJ:   1

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following statements is true of silane in composite materials?
a. Silane forms the dispersed inorganic filler particles.
b. Silane forms the dispersed organic filler particles.
c. Silane is a coupling agent on the filler particles.
d. Silane forms the resin matrix.

 

 

ANS:  C

 

  Feedback
A Silane is a coupling agent that allows bonding of particles. It does not form them.
B Silane is a coupling agent that allows bonding of particles. It does not form them.
C Silane is a coupling agent on the filler particles. Its purpose is to produce a good bond between the matrix and the filler.
D Silane is a coupling agent that allows bonding of particles. It does not form them.

 

 

DIF:    Knowledge     REF:   p.  44             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which type of composite has the smallest filler particle size?
a. Microhybrid
b. Microfilled
c. Nanofilled
d. Packable
e. Flowable

 

 

ANS:  C

 

  Feedback
A Microhybrid has particle sizes measured in microns. Nanofilled particles are measured in smaller nanometers.
B Microfilled has particle sizes measured in microns. Nanofilled particles are measured in smaller nanometers.
C Nanofilled composites have the smallest particle size.
D Packable has particle sizes measured in microns. Nanofilled particles are measured in smaller nanometers.
E Flowable has particle sizes measured in microns. Nanofilled particles are measured in smaller nanometers.

 

 

DIF:    Knowledge     REF:   p.  43             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which type of setting reaction is utilized by a composite restorative material?
a. Gelation
b. Reduction
c. Hysteresis
d. Polymerization

 

 

ANS:  B

 

  Feedback
A Gelation has reactions not associated with direct esthetic restorations.
B The setting reaction of a composite restorative material is polymerization.
C Hysteresis has reactions not associated with direct esthetic restorations.
D Reduction has reactions not associated with direct esthetic restorations.

 

 

DIF:    Knowledge     REF:   p.  45             OBJ:   4

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. In a visible, light-curing, direct composite system, which component is the light absorbed by?
a. Diketone, which starts the polymerization reaction in the presence of an organic peroxide initiator
b. Diketone, which starts the polymerization reaction in the presence of an organic amine
c. Organic peroxide initiator and organic amine accelerator
d. Organic peroxide initiator alone

 

 

ANS:  B

 

  Feedback
A In a visible, light-curing, direct composite system, the light is absorbed by a diketone, which starts the polymerization reaction in the presence of an organic amine.
B In a visible, light-curing, direct composite system, the light is absorbed by a diketone, which starts the polymerization reaction in the presence of an organic amine.
C Organic peroxide initiator activates the two-paste, self-cure systems.
D Organic peroxide initiator activates the two-paste, self-cure systems.

 

 

DIF:    Knowledge     REF:   p.  45             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following statements is true of polymerization shrinkage of composite restorative materials?
a. Microfilled composites shrink less than microhybrid composites, because microhybrid composites have less resin.
b. Stresses from polymerization shrinkage cannot exceed the bond strength of a composite to tooth structure.
c. Incremental addition and polymerization of composite in layers will reduce the effective shrinkage.
d. Bulk addition of composite will reduce the effective shrinkage.

 

 

ANS:  D

 

  Feedback
A Microhybrid composites shrink less during setting than microfilled types, because the microhybrid composites have less resin.
B Stresses from polymerization shrinkage can exceed the bond strength of a composite to tooth structure, resulting in marginal leakage.
C Incremental addition and polymerization of composite in layers will reduce the effective shrinkage.
D Bulk addition will increase the effective shrinkage.

 

 

DIF:    Knowledge     REF:   p.  44             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. The more resin matrix, the _________ the linear coefficient of thermal expansion, because the polymer has a _________ value than the filler.
a. higher; higher
b. higher; lower
c. lower; higher
d. lower; lower

 

 

ANS:  A

 

  Feedback
A The more resin matrix, the higher the linear coefficient of thermal expansion, because the polymer has a higher value than the filler.
B Microfilled composites have higher values for thermal expansion than microhybrid composites. Therefore the more resin matrix a material has, the higher the linear coefficient of thermal expansion. The lower the matrix, the lower the value.
C Microfilled composites have higher values for thermal expansion than microhybrid composites. Therefore the more resin matrix a material has, the higher the linear coefficient of thermal expansion. The lower the matrix, the lower the value.
D Microfilled composites have higher values for thermal expansion than microhybrid composites. Therefore the more resin matrix a material has, the higher the linear coefficient of thermal expansion. The lower the matrix, the lower the value.

 

 

DIF:    Analysis         REF:   p.  46             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following statements is correct when contrasting microhybrid composites with microfilled composites?
a. Microhybrid composites have higher water sorption.
b. Microfilled composites have higher compressive strength.
c. Microhybrid composites have more polymerization shrinkage.
d. Microhybrid composites have a lower elastic modulus in compression.
e. Microfilled composites have a higher linear coefficient of thermal expansion.

 

 

ANS:  D

 

  Feedback
A Microhybrid composites have lower water sorption.
B Microfilled composites have a higher linear coefficient of thermal expansion.
C Microhybrid composites have less polymerization shrinkage.
D Microhybrid composites have a higher elastic modulus in compression than microfilled composites.
E Microfilled composites have a lower compressive strength than microhybrid composites.

 

 

DIF:    Comprehension                              REF:   p.  43             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. A bond strength of _____ MPa is an estimated requirement to prevent marginal gaps as a result of polymerization shrinkage during placement of composite restorations.
a. 0.01
b. 1
c. 10
d. 20

 

 

ANS:  D

 

  Feedback
A 0.01 is well below the estimated MPa requirement and would exacerbate the potential for marginal gaps.
B 1 is well below the estimated MPa requirement and would exacerbate the potential for marginal gaps.
C 10 is well below the estimated MPa requirement and would exacerbate the potential for marginal gaps.
D A bond strength of 20 MPa is an estimated requirement to prevent marginal gaps as a result of polymerization shrinkage during placement of composite restorations.

 

 

DIF:    Knowledge     REF:   p.  45             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Sensitivity associated with placement of composite restorations has been reported in about ____% of cases.
a. 1
b. 10
c. 25
d. 50
e. 75

 

 

ANS:  B

 

  Feedback
A Sensitivity associated with placement of composite restorations has been reported in about 10% of cases.
B Sensitivity associated with placement of composite restorations has been reported in about 10% of cases.
C Sensitivity associated with placement of composite restorations has been reported in about 10% of cases.
D Sensitivity associated with placement of composite restorations has been reported in about 10% of cases.
E Sensitivity associated with placement of composite restorations has been reported in about 10% of cases.

 

 

DIF:    Knowledge     REF:   p.  47             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Currently acceptable composites for posterior applications require clinical studies demonstrating a loss of surface contour less than _____ µm over a 5-year period.
a. 5
b. 50
c. 100
d. 250
e. 5000

 

 

ANS:  D

 

  Feedback
A Currently acceptable composites for posterior applications require clinical studies demonstrating a loss of surface contour less than 250 µm over a 5-year period, or an average of 50 µm per year of clinical service.
B Currently acceptable composites for posterior applications require clinical studies demonstrating a loss of surface contour less than 250 µm over a 5-year period, or an average of 50 µm per year of clinical service.
C Currently acceptable composites for posterior applications require clinical studies demonstrating a loss of surface contour less than 250 µm over a 5-year period, or an average of 50 µm per year of clinical service.
D Currently acceptable composites for posterior applications require clinical studies demonstrating a loss of surface contour less than 250 µm over a 5-year period, or an average of 50 µm per year of clinical service.
E Currently acceptable composites for posterior applications require clinical studies demonstrating a loss of surface contour less than 250 µm over a 5-year period, or an average of 50 µm per year of clinical service.

 

 

DIF:    Knowledge     REF:   p.  47             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. What is/are the most likely cause(s) of sensitivity following placement of composite restorations?
a. Induced internal stress
b. An occlusal interference
c. Microleakage of bacteria
d. The use of acid etchant during placement
e. Both B and D

 

 

ANS:  E

 

  Feedback
A B and D are correct.
B Effective finishing and polishing of the restoration at the time of placement will eliminate high occlusion.
C B and D are correct.
D Use of a low-strength liner prior to etching will protect the pulp.
E The most likely causes of sensitivity following placement of composite restorations are induced internal stress and microleakage of bacteria.

 

 

DIF:    Comprehension                              REF:   p.  47             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites and g. varnishes, bases, and liners

MSC:  NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. With _______-generation bond agents, etching and priming are accomplished at the same time, and rinsing is not required.
a. third
b. fourth
c. fifth
d. sixth

 

 

ANS:  D

 

  Feedback
A Third-generation bond agents are all associated with multiple steps.
B Fourth-generation bond agents are all associated with multiple steps.
C Fifth-generation bond agents are all associated with multiple steps.
D With sixth- and seventh-generation bonding agents, etching and priming are accomplished at the same time, and rinsing is not required.

 

 

DIF:    Knowledge     REF:   p.  47             OBJ:   4

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to g. varnishes, bases, and liners

MSC:  NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following statements is true of single- and two-paste composites?
a. Single-paste composites are light activated.
b. Single-paste composites may be dual cured.
c. Compules are a component of two-paste composites.
d. An automix syringe is a component of single-paste composites.

 

 

ANS:  A

 

  Feedback
A Single-paste composites are light activated.
B Some forms of two-paste composites are dual cured.
C Compules are a component of single-paste composites.
D An automix syringe is a component of two-paste composites.

 

 

DIF:    Knowledge     REF:   p.  47             OBJ:   4

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. What is/are (an) advantage(s) of placing composite into the plastic tip of a syringe and injecting it into the cavity preparation?
a. Allows the use of large mixes
b. Facilitates placement of the material in the areas of retention
c. Reduces incorporation of voids into the composite during insertion
d. A, B, and C are correct.
e. Only B and C are correct.

 

 

ANS:  E

 

  Feedback
A Using a syringe for placement of composite resin allows the operator to place smaller increments of material.
B B and C are correct.
C B and C are correct.
D Advantages of placing composite into the plastic tip of a syringe and injecting it into the cavity preparation include that the syringe allows the use of small mixes, reduces incorporation of voids into the composite during insertion, and facilitates placement of the material in the areas of retention.
E B and C are correct.

 

 

DIF:    Comprehension                              REF:   p.  47             OBJ:   4

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following statements is correct about flowable composite resins?
a. Are recommended for low-stress-bearing restorations
b. Have a high modulus of elasticity
c. Have a low modulus of elasticity
d. A and B
e. A and C

 

 

ANS:  E

 

  Feedback
A Flowable composites are recommended for low-stress-bearing restorations. They have a low modulus of elasticity, which is the ratio of stress to strain.
B Flowable composites are recommended for low-stress-bearing restorations. They have a low modulus of elasticity, which is the ratio of stress to strain.
C Flexible materials have a low modulus of elasticity, and stiff materials have a high modulus of elasticity.
D Flowable composites are recommended for low-stress-bearing restorations. They have a low modulus of elasticity, which is the ratio of stress to strain.
E Flowable composites are recommended for low-stress-bearing restorations. They have a low modulus of elasticity, which is the ratio of stress to strain.

 

 

DIF:    Comprehension                              REF:   p.  48             OBJ:   7

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following statements is true of flowable composites when contrasted with microhybrid composites?
a. They have lower viscosity than microhybrid composites.
b. They have a higher filler content than microhybrid composites.
c. They have higher wear resistance than microhybrid composites.
d. They exhibit lower polymerization shrinkage than microhybrid composites.

 

 

ANS:  D

 

  Feedback
A Flowable composites have lower viscosity than microhybrid composites.
B Flowable composites have a lower filler content than microhybrid composites.
C Flowable composites have lower wear resistance than microhybrid composites.
D This makes them more flexible and well suited for fabrication areas, but they do exhibit more polymerization shrinkage.

 

 

DIF:    Knowledge     REF:   p.  48             OBJ:   5

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which type of direct composite has a wear rate most similar to dental amalgam?
a. Packable composite
b. Flowable composite
c. Microfilled composite
d. Microhybrid composite

 

 

ANS:  A

 

  Feedback
A Packable has a low wear rate (3.5 µm/year), similar to that of amalgam.
B Flowable has higher wear rates than are recommended for stress-bearing areas.
C Microfilled has higher wear rates than are recommended for stress-bearing areas.
D Microhybrid has higher wear rates than are recommended for stress-bearing areas.

 

 

DIF:    Knowledge     REF:   p.  49             OBJ:   7

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following statements is true when contrasting composite core material with amalgam?
a. Composite can be finished immediately and prepared for a crown at the same appointment, whereas amalgam cannot be prepared for a crown at the same appointment.
b. Composite materials have good color under ceramic, but amalgam does not.
c. Composite materials are more difficult to contour than amalgam materials.
d. A, B, and C are correct.
e. A and B are correct.

 

 

ANS:  E

 

  Feedback
A Only A and B are correct.
B Only A and B are correct.
C Composite resin materials are easier to contour than amalgam because of the increased working time and the ability to not overfill.
D Only A and B are correct.
E Amalgam cannot be prepared for a crown at the same time as the placement appointment because of delayed setting expansion or contraction. Composite materials have better color under ceramic while the silver-gray color of amalgam can bleed through. Composite materials are easier to contour than amalgam materials.

 

 

DIF:    Comprehension                              REF:   p.  51             OBJ:   7

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Advantages of composite provisional materials over acrylic provisional materials include
a. lower cost.
b. harder, more brittle texture.
c. doughy stage for easier handling.
d. lower heat release during curing.

 

 

ANS:  D

 

  Feedback
A They are more expensive.
B They are harder and more brittle, which are listed in Table 4-5 as disadvantages of composite.
C Acrylic is listed as having a doughy stage for easier handling than composite.
D Composite provisional materials release less heat during curing than acrylic provisional materials.

 

 

DIF:    Knowledge     REF:   p.  51             OBJ:   5

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to f. Temporary restorative materials

MSC:  NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. When composites are repaired, the repair bond strength is about ________% of the cohesive strength of the original composite.
a. 100 to 120
b. 80 to 100
c. 60 to 80
d. 40 to 60
e. 20

 

 

ANS:  C

 

  Feedback
A Option A is higher than the given percent rate.
B Option B is higher than the given percent rate.
C The repair bond strength is about 60 to 80% of the cohesive strength of the original composite.
D Option D is lower than the given percent rate.
E Option E is lower than the given percent rate.

 

 

DIF:    Knowledge     REF:   p.  51             OBJ:   4

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following do compomers contain?
a. Dimethacrylate (Bis-GMA)
b. Urethane dimethacrylate (UDMA) oligomers
c. Monomers modified by polyacid groups with fluoride-releasing silicate glasses.
d. A powder of aluminosilicate glass and a water solution of polymers and copolymers of acrylic acid.

 

 

ANS:  C

 

  Feedback
A Bis-GMA is associated with composite resins, microfilled, and microhybrids.
B UDMA is associated with composite resins, microfilled, and microhybrids.
C Compomers contain monomers modified by polyacid groups with fluoride-releasing silicate glasses.
D Option D is associated with glass ionomer.

 

 

DIF:    Knowledge     REF:   p.  52             OBJ:   10

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. It is recommended that glass ionomer restorations be used in Class _____ restorations where esthetics is not critical.
a. I
b. II
c. III
d. IV
e. V

 

 

ANS:  E

 

  Feedback
A Class Is are load-bearing areas, and glass ionomers are not strong enough to withstand biting forces.
B Class IIs are load-bearing areas, and glass ionomers are not strong enough to withstand biting forces.
C Class IIIs are highly visible areas in which esthetics is an issue.
D Class IVs are highly visible areas in which esthetics is an issue.
E It is recommended that glass ionomer restorations be used in Class V restorations where esthetics is not critical. They are recommended for patients with high risk of caries.

 

 

DIF:    Knowledge     REF:   p.  52             OBJ:   13

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to e. glass ionomers   MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. What are the components of the smear layer?
a. Hydroxyapatite and partially denatured collagen
b. Calcium hydroxide
c. Adhesive
d. Etchant
e. Primer

 

 

ANS:  A

 

  Feedback
A The smear layer consists of hydroxyapatite and partially denatured collagen.
B Calcium hydroxide is used as a low-strength liner and will stimulate the formation of reparative dentin.
C Adhesive is related to the bonding process.
D Etchant removes the smear layer and prepares enamel and dentin to receive the esthetic restoration.
E Primer is related to the bonding process.

 

 

DIF:    Knowledge     REF:   p.  54             OBJ:   23

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following statements is true regarding composite curing times?
a. Darker shades require shorter curing times than lighter shades.
b. Curing times with PAC lights are longer than for QTH or LED lights.
c. Microhybrid composites require longer curing times than microfilled composites.
d. More opaque composites require longer curing times than more translucent composites.

 

 

ANS:  D

 

  Feedback
A Shade should not affect curing time.
B QTH or LED lights are more intense than PAC lights.
C Microfilled composites take longer to cure than microhybrid composites.
D More opaque composites require longer curing times than more translucent composites.

 

 

DIF:    Knowledge     REF:   p.  55             OBJ:   27

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Glass ionomers are typically reserved for which type of restoration?
a. Posterior interproximal lesions
b. Anterior interproximal lesions
c. Cervically eroded areas
d. Pit and fissure lesions

 

 

ANS:  C

 

  Feedback
A Posterior interproximal lesions require a restorative material with more strength and wear resistance.
B Anterior interproximal lesions require a restorative material with more strength and wear resistance.
C Areas of cervical erosion benefit from using glass ionomer.
D Pit and fissure lesions require a restorative material with more strength and wear resistance.

 

 

DIF:    Knowledge     REF:   p.  52             OBJ:   13

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to e. glass ionomers   MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following is not true about composite resin materials?
a. High strength
b. Esthetically pleasing
c. High wear resistance
d. High fluoride content

 

 

ANS:  D

 

  Feedback
A Composite resins are esthetically pleasing, strong, and have high wear resistance.
B Composite resins are esthetically pleasing, strong, and have high wear resistance.
C Composite resins are esthetically pleasing, strong, and have high wear resistance.
D Composite resins have little to no fluoride content.

 

 

DIF:    Knowledge     REF:   p.  42             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. What does the composition of composite resin material consist of?
a. Resin matrix
b. Organic filler particles
c. Inorganic filler particles
d. A and B are correct.
e. A and C are correct.

 

 

ANS:  E

 

  Feedback
A Composites consist of three phases: resin matrix, dispersed inorganic filler particles, and silane coupling agent on the filler particles to produce a good bond between the matrix and the filler.
B Filler particles in composite resin materials include quartz, lithium aluminum silicate, and barium, strontium, zinc, or ytterbium glasses. All are inorganic materials.
C Filler particles in composite resin materials include quartz, lithium aluminum silicate, and barium, strontium, zinc, or ytterbium glasses. All are inorganic materials.
D A and C are correct.
E A and B are correct.

 

 

DIF:    Knowledge     REF:   p.  44             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following organic fillers are radiopaque?
a. Lithium aluminum silicate
b. Crystalline silica
c. Strontium
d. A, B, and C are all correct.

 

 

ANS:  C

 

  Feedback
A Lithium aluminum silicate fillers are radiolucent.
B Crystalline silica fillers are radiolucent.
C Fine fillers that contain barium, strontium, zinc, or ytterbium atoms are radiopaque with the radiopacity proportional to the volume fraction of the filler.
D Option C is the only correct answer.

 

 

DIF:    Knowledge     REF:   p.  43             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following organic fillers are radiolucent?
a. Lithium aluminum silicate
b. Crystalline silica
c. Strontium
d. A and B are correct.
e. B and C are correct.

 

 

ANS:  D

 

  Feedback
A Quartz (crystalline silica) and lithium aluminum silicate are both radiolucent.
B A and B are correct.
C Strontium is radiopaque.
D Quartz (crystalline silica) and lithium aluminum silicate are both radiolucent.
E A and B are correct.

 

 

DIF:    Knowledge     REF:   p.  44             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. What component initiates the polymerization reaction of a self-cure composite resin?
a. Diketone in the presence of an organic amine
b. Visible curing light system
c. Organic peroxide initiator
d. Dimethacrylate

 

 

ANS:  C

 

  Feedback
A In self-curing systems, polymerization is accomplished with an organic peroxide initiator and an organic amine accelerator.
B Curing lights relate to a one-paste composite system that uses visible light to cure.
C In self-curing systems, polymerization is accomplished with an organic peroxide initiator and an organic amine accelerator.
D Dimethacrylate is a resin matrix.

 

 

DIF:    Knowledge     REF:   p.  45             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. What occurs if bond strength is exceeded and gaps occur at the cavosurface margin?
a. Inadequate cure
b. Inadequate etch
c. Saliva contamination
d. Polymerization shrinkage

 

 

ANS:  D

 

  Feedback
A Inadequate cure affects adhesion rather than strength.
B Inadequate etch affects adhesion rather than strength.
C Saliva contamination affects adhesion rather than strength.
D Even with acid etching of enamel and dentin and use of bonding agents, stresses from polymerization shrinkage can exceed the bond strength of a composite to tooth structure, and, as a result, marginal leakage can occur.

 

 

DIF:    Knowledge     REF:   p.  46             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following have the highest rates of thermal expansion?
a. Nanofilled composites
b. Microfilled composites
c. Macrofilled composites
d. Microhybrid composites

 

 

ANS:  B

 

  Feedback
A Nanofilled composites have lower values of thermal expansion.
B Microfilled composites have higher values for thermal expansion than microhybrid composites.
C Macrofilled composites have lower values of thermal expansion.
D Microhybrid composites have lower values of thermal expansion.

 

 

DIF:    Knowledge     REF:   p.  46             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Why would a dentin bonding agent not be used when placing a resin-modified glass ionomer?
a. It decreases the release of fluoride
b. Using a curing light is not necessary.
c. The material does not bond to tooth structure.
d. The material is used for temporary restorations.

 

 

ANS:  A

 

  Feedback
A Resin-modified glass ionomers are recommended for patients with a high caries rate. The use of dentinal bonding agents decreases the release of fluoride.
B Resin-modified glass ionomers can either be light cured or self-cured.
C Resin-modified glass ionomers bond to tooth structure.
D Resin-modified glass ionomers are used as a permanent restoration because they release the fluoride ion and they are more esthetically pleasing than glass ionomer cements.

 

 

DIF:    Knowledge     REF:   p.  53             OBJ:   17

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to d. dentin bonding materials

MSC:  NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Why are composite materials for anterior restorations used over other restorative materials?
a. Minimal surface erosion
b. Resistance to biting forces
c. Low rate of recurrent caries
d. Minimal degradation in the oral environment

 

 

ANS:  C

 

  Feedback
A The problem with composites is the loss of surface contour of composite restorations in the mouth.
B Anterior restorations suffer abrasive wear from chewing and toothbrushing.
C Clinical studies have shown that composites are superior materials for anterior restorations in which esthetics is essential and occlusal forces are low. Color changes are minimal; marginal adaptation is good; and recurrent decay is low.
D Anterior restorations suffer from erosive wear from degradation of the composite in the oral environment.

 

 

DIF:    Knowledge     REF:   p.  46             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. How can postoperative sensitivity be avoided?
a. Placing larger layers of material
b. Using a high-strength base
c. Using a low-strength liner
d. All of the above are correct.
e. Only B and C are correct.

 

 

ANS:  D

 

  Feedback
A Postoperative sensitivity can be reduced by placing and curing the layers in small increments to limit the amount of polymerization shrinkage.
B B and C are correct answers.
C B and C are correct answers.
D Incremental placement of the composite, excellent isolation during placement, and use of bases to protect the pulp are recommended solutions.
E B and C are correct answers.

 

 

DIF:    Comprehension                              REF:   p.  47             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to g. varnishes, bases and liners

MSC:  NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. In the event that an esthetic material is required for a direct, posterior, load-bearing restoration, _________ composite is the material of choice.
a. core
b. flowable
c. packable
d. laboratory

 

 

ANS:  C

 

  Feedback
A Core composites are used to replace tooth structure prior to the placement of a crown.
B Flowable composites are not strong enough to place in load-bearing areas.
C These composites (see Table 4-2) are recommended for use in Class I, II, and VI (MOD) cavity preparations.
D Laboratory composites are used for indirect restorations.

 

 

DIF:    Knowledge     REF:   p.  49             OBJ:   7

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Compomers are recommended for patients with ______________ risk.
a. low caries
b. medium caries
c. high caries
d. any level of

 

 

ANS:  B

 

  Feedback
A Low caries risk would not need a material containing a fluoride ion.
B Compomers are recommended for patients with medium caries risk.
C High caries risk might require a material with a higher level of fluoride release.
D Not all patients are candidates for compomer restorative materials.

 

 

DIF:    Knowledge     REF:   p.  51             OBJ:   9

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Why is it important to finish and polish a composite restoration after it is placed?
a. Reduces staining
b. Prevents percolation
c. Eliminates microleakage
d. Maintains good oral hygiene

 

 

ANS:  D

 

  Feedback
A Stain is associated with the amount of exposed matrix in the composite material.
B Thermal expansion is very close to that of tooth structure. The material expands and contracts at a similar rate as the tooth.
C Microleakage occurs when a margin is exposed. If the restoration has been adequately finished at the time of placement, microleakage should not be a factor.
D A smooth surface helps prevent the retention of plaque.

 

 

DIF:    Knowledge     REF:   p.  48             OBJ:   5

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

  1. Which of the following esthetic restorative materials is best suited for Class I posterior restorations?
a. Microfilled
b. Microhybrid
c. Glass ionomer
d. Bulk composite

 

 

ANS:  D

 

  Feedback
A Microfilled materials are better suited for anterior esthetic restorations in low-stress-bearing areas.
B Microhybrid materials are better suited for anterior esthetic restorations in low-stress-bearing areas.
C Glass ionomer cements are best utilized along the gum line, in class V restorations, and for patients with high caries rates.
D Bulk resin materials have larger filler particles that allow it to hold up under the stresses of chewing.

 

 

DIF:    Knowledge     REF:   p.  49             OBJ:   7

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites         MSC:   NMDHE, 6.0 Providing Supportive Treatment Services, 6.5 General

 

SHORT ANSWER

 

  1. Compare and contrast microfilled and microhybrid composite resin materials.

 

ANS:

Microhybrid materials contain blends of fine and microfine filler particles with as much as 84% filler by weight. The microfine filler particles fit in spaces between the fine filler particles, producing a total filler concentration of 70% by volume, which results in improved properties. Microfilled composites contain microfine fillers with high surface areas. Only 35% to 50% by volume of these particles can be used with the resin matrix and still produce a paste of acceptable viscosity.

 

DIF:    Analysis         REF:   p.  43             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Explain the process of polymerization shrinkage of composite resin materials and why it is significant in the life of a restoration.

 

ANS:

Microhybrid composites shrink less during setting than microfilled types because the microhybrid composites have less resin. Even with acid etching of enamel and dentin and use of bonding agents, stresses from polymerization shrinkage can exceed the bond strength of a composite to tooth structure, and, as a result, marginal leakage can occur.

 

DIF:    Comprehension                              REF:   p.  45             OBJ:   3

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

 

  1. Compare and contrast direct placement resins to laboratory resins.

 

ANS:

Composite resin materials have a shorter life span than indirect or laboratory resins. Direct placement resins stain easily and wear over a relatively short period of time when compared to laboratory resins. Crowns, inlays, veneers bonded to metal substructures, and metal-free bridges are prepared indirectly on dies from composites processed in the laboratory (see Table 4-2) using various combinations of light, heat, pressure, and vacuum, which increase the polymerization and the wear resistance.

 

DIF:    Application    REF:   p.  51             OBJ:   5

TOP:   CDA, GC, III Chairside Dental Materials (Preparation, Manipulation, and Application) B, 1, Describe how to prepare, mix, deliver, and store restorative materials, including but not limited to c. composites

MSC:  NBDHE, 6.0 Providing Supportive Treatment Services, 6.1 Properties and Manipulation of Materials

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