Chapter 8: Composites

1.) Which of the following is a direct-placement esthetic material?

a) composite resin

b) silver amalgam

c) porcelain inlay

d) full gold crown

a) composite resin

b) silver amalgam

c) porcelain inlay

d) full gold crown

2.) Which of the following materials is responsible for adhering particles to the resin matrix?

a) silane

b) colloidal

c) surfactant

d) hydrophobic

a) silane

b) colloidal

c) surfactant

d) hydrophobic

3.) Which of the following is correct regarding filler particles?

1. Filler particles make composite stronger and more wear resistant.

2. Filler particles are organic.

3. Filler particles reduce the amount of shrinkage due to less resin matrix to set.

4. Fillers help to control translucency of the composite by their effect on the scattering of light.

a) 1, 2, 3, 4

b) 1, 2, 3

c) 1, 3, 4

d) 1, 3

a) 1, 2, 3, 4

b) 1, 2, 3

c) 1, 3, 4

d) 1, 3

4.) Polymerization occurs when ______ molecular-weight resin molecules called monomers join together to form long-chain, _______ molecular-weight molecules called polymers.

a) low; low

b) low; high

c) high; high

d) high; low

a) low; low

b) low; high

c) high; high

d) high; low

5.) What is the purpose of a tertiary amine in chemical cure composite resin?

a) accelerates polymerization

b) activates the polymerization process

c) activates the catalyst for polymerization

d) inhibits chemical reaction to slow polymerization

a) accelerates polymerization

b) activates the polymerization process

c) activates the catalyst for polymerization

d) inhibits chemical reaction to slow polymerization

6.) What is the maximum incremental depth of composite resin as it is placed?

a) 1.0

b) 2.0

c) 4.0

d) 8.0

a) 1.0

b) 2.0

c) 4.0

d) 8.0

7.) Which of the following is correct regarding nanohybrid composite resins?

a) these are weak composites

b) these composites cannot be polished to a high shine

c) the shrinkage has been reduced from roughly 2-3% with earlier composites to less than 1% with nanohybrids

d) with more resin than previous generations, these composites shrink less when polymerized

a) these are weak composites

b) these composites cannot be polished to a high shine

c) the shrinkage has been reduced from roughly 2-3% with earlier composites to less than 1% with nanohybrids

d) with more resin than previous generations, these composites shrink less when polymerized

8.) Which statement is correct about flowable composite resins?

a) They are useful for class I but not class V restorations.

b) They are useful as liners in large cavity preparations because they adapt to the preparation better than more viscous materials such as hybrid and packable composites.

c) They are high-viscosity, light-cured resins that may be lightly filled (about 40%) or more heavily-filled (up to 70%).

d) They have a high elastic modulus, which allows them to cushion stresses created by polymerization shrinkage or heavy occlusal loads.

a) They are useful for class I but not class V restorations.

b) They are useful as liners in large cavity preparations because they adapt to the preparation better than more viscous materials such as hybrid and packable composites.

c) They are high-viscosity, light-cured resins that may be lightly filled (about 40%) or more heavily-filled (up to 70%).

d) They have a high elastic modulus, which allows them to cushion stresses created by polymerization shrinkage or heavy occlusal loads.

9.) How do bulk-fill composite resins differ from conventional composite resins?

1. Permits placing increments of 4mm or more

2. They are more translucent, which makes it difficult to match shades

3. Bulk-fill composite resins do not work well for class II restorations because of the depth of the proximal box

4. Polymerization shrinkage has been reduced by adding special modifiers to relieve stress in the restoration during curing

a) 1, 2, 3, 4

b) 1, 2, 3

c) 1, 2

d) 1

a) 1, 2, 3, 4

b) 1, 2, 3

c) 1, 2

d) 1

10.) Which of the following is correct regarding polymerization shrinkage of light cured composite resin restorations?

a) microfills and flowable shrink less than hybrids and packables

b) the greater the resin content of the composite, the less it will shrink

c) recent research indicates that the composite resin material does not shrink toward the light

d) as the composite polymerizes and shrinks it tends to pull towards the walls of the preparation that are bonded

a) microfills and flowable shrink less than hybrids and packables

b) the greater the resin content of the composite, the less it will shrink

c) recent research indicates that the composite resin material does not shrink toward the light

d) as the composite polymerizes and shrinks it tends to pull towards the walls of the preparation that are bonded

11.) For composite restorative materials, the greater the filler content, the _______ the coefficient of thermal expansion (CTE), and the greater the resin content, the ________ the CTE.

a) greater; greater

b) greater; lower

c) lower; greater

d) lower; lower

a) greater; greater

b) greater; lower

c) lower; greater

d) lower; lower

12.) Why does it take longer to cure darker shades of composite resin than lighter shades?

a) light is more readily absorbed by lighter colors than darker colors

b) light is not transmitted through dark material as it does through lighter material

c) darker materials are denser, and it takes longer to cure them

d) darker materials disperse light rather than absorb it

a) light is more readily absorbed by lighter colors than darker colors

b) light is not transmitted through dark material as it does through lighter material

c) darker materials are denser, and it takes longer to cure them

d) darker materials disperse light rather than absorb it

13.) During incremental additoin of composite resin, how will each additional increment bond to the previously placed increment of composite?

a) if etchant is used between layers

b) if etchant and primer are used between layers

c) if etchant, primer, and bond agent are used between layers

d) subsequent layers adhere to the oxygen inhibited layer of uncured resin

a) if etchant is used between layers

b) if etchant and primer are used between layers

c) if etchant, primer, and bond agent are used between layers

d) subsequent layers adhere to the oxygen inhibited layer of uncured resin

14.) It is recommended to _________ to reduce sticking of the composite material to the placement instrument.

a) use a little of an unfilled resin

b) use a little of the bonding agent

c) use a specially coated instrument

d) wet the composite instrument with alcohol

a) use a little of an unfilled resin

b) use a little of the bonding agent

c) use a specially coated instrument

d) wet the composite instrument with alcohol

15.) Which of the following types of curing lights is currently the most widely used?

a) Plasma arc (PAC)

b) laser (initially argon laser)

c) light-emitting diode (LED)

d) halogen (quartz-tungsten-halogen, or QTH)

a) Plasma arc (PAC)

b) laser (initially argon laser)

c) light-emitting diode (LED)

d) halogen (quartz-tungsten-halogen, or QTH)

16.) Which of the following are advantages of indirect-placement composite resin restorations over directly placed composites?

1. Eliminate polymerization shrinkage

2. Reduced wear seen with direct composites

3. More stress is created internally on the composite and the walls of the cavity preparation

4. The indirect-placement composite restorations contacts and occlusions are checked prior to cementation

a) 1, 2, 3, 4

b) 1, 2, 3

c) 1, 2, 4

d) 2, 4

a) 1, 2, 3, 4

b) 1, 2, 3

c) 1, 2, 4

d) 2, 4

17.) Which type of matrix system would be used if a significant amount of tooth structure is missing?

a) crown form

b) circumferential

c) sectional

d) cervical

a) crown form

b) circumferential

c) sectional

d) cervical

18.) Which of the following materials is/are not radiopaque?

a) quartz

b) lithium

c) barium

d) strontium

a) quartz

b) lithium

c) barium

d) strontium

19.) To avoid shrinkage, how should composite resins be placed into a preparation?

a) in large increments

b) in small increments

c) the material does not shrink

a) in large increments

b) in small increments

c) the material does not shrink

20.) Which of the following is correct regarding a core buildup?

a) mechanical retention is not necessary

b) often contain pigments to color them

c) a bulk-filled composite is used

d) are subject to microleakage

a) mechanical retention is not necessary

b) often contain pigments to color them

c) a bulk-filled composite is used

d) are subject to microleakage

21.) Which is true regarding placement of a Class II composite resin?

a) decreases curing time in the proximal box

b) cure the proximal box from the occlusal surface

c) high recurrent caries rate due to incomplete curing of the gingival margin

d) matrix bands may compromise a thorough cure of the resin material

a) decreases curing time in the proximal box

b) cure the proximal box from the occlusal surface

c) high recurrent caries rate due to incomplete curing of the gingival margin

d) matrix bands may compromise a thorough cure of the resin material

22.) Which of the following are factors that adversely affect curing?

1. short curing time

2. weak light source

3. incorrectly placed light guide

4. infection control barrier covering the light guide

a) 1, 2, 3, 4

b) 1, 2, 3

c) 2, 3, 4

d) 1, 3

a) 1, 2, 3, 4

b) 1, 2, 3

c) 2, 3, 4

d) 1, 3

23.) What is the organic matrix of composite resins made up of?

a) BIS-GMA

b) glass

c) silica

d) quartz

a) BIS-GMA

b) glass

c) silica

d) quartz

24.) Which classification of restoration is best suited for microfilled composite materials?

1. Class I

2. Class II

3. Class III

4. Class IV

5. Class V

a) 1, 2, 3, 4, 5

b) 1, 3, 5

c) 3, 5

d) 5

a) 1, 2, 3, 4, 5

b) 1, 3, 5

c) 3, 5

d) 5

25.) How do microhybrid composite resins compare to nanohybrid composite resins? (Select all that apply.)

a) a microhybrid resin’s rate of shrinkage is reduced by 1% as compared with nanohybrid composite resins

b) a nanohybrid resin uses nanosized particles which reduces the amount of resin matrix allowing the material to be used for both anterior and posterior restorations

c) microhybrid composite resins contain a combination of small particles and microfine particles

d) nanohybrids retain their highly polished appearance longer than earlier composite resins

a) a microhybrid resin’s rate of shrinkage is reduced by 1% as compared with nanohybrid composite resins

b) a nanohybrid resin uses nanosized particles which reduces the amount of resin matrix allowing the material to be used for both anterior and posterior restorations

c) microhybrid composite resins contain a combination of small particles and microfine particles

d) nanohybrids retain their highly polished appearance longer than earlier composite resins

26.) Which of the following lead to composite restoration failure? (Select all that apply.)

a) tooth fracture

b) poor diet and oral hygiene

c) lack of mechanical retention

d) defects in the restoration’s surface

a) tooth fracture

b) poor diet and oral hygiene

c) lack of mechanical retention

d) defects in the restoration’s surface

27.) Define the following terms:

• Microfilled composite

• Macrofilled composite

• Hybrid composite

• Flowable composite

• Nano-ionomers

• Microfilled composite: a composite that contains very small filler particles averaging 0.04mm in diameter

• Macrofilled composite: an early generation of composite that contained filler particles ranging from 10 to 100 mm in diameter

• Hybrid composite: a composite that contains both macrofill and microfill particles

• Flowable composite: a light-cured, low viscosity composite resin that contains fewer filler particles

• Nano-ionomers: a composite that contains all nano-sized fillers to enhance physical properties

28.) Which technique applies layers of composite of different shades or degrees of opacity or translucency to obtain a good color match?

a) veneer technique

b) hybrid technique

c) layered technique

d) sandwich technique

a) veneer technique

b) hybrid technique

c) layered technique

d) sandwich technique

RQ

1.) The major components of composite dental materials include all of the following except one. Which one is this exception?

a) Bonding agent

b) Resin matrix

c) Coupling agent

d) Fillers

a) Bonding agent

b) Resin matrix

c) Coupling agent

d) Fillers

RQ

2.) Composite resins are often classified according to their:

a) Strength

b) Polishability

c) Resin content

d) Filler particle size

a) Strength

b) Polishability

c) Resin content

d) Filler particle size

RQ

3.) The shortcomings of flowable composites as compared with more viscous microhybrid composites include all of the following except one. Which one is this exception?

a) They are weaker.

b) They wear faster.

c) They shrink more when polymerized.

d) They are more difficult to polish.

a) They are weaker.

b) They wear faster.

c) They shrink more when polymerized.

d) They are more difficult to polish.

RQ

4.) What is the purpose of a silane coupling agent for composite resins?

a) To improve the bond between the filler particles and the resin matrix

b) To help the composite retain its color

c) To reduce the oxygen-inhibited layer

d) To help the various resin layers stick together

a) To improve the bond between the filler particles and the resin matrix

b) To help the composite retain its color

c) To reduce the oxygen-inhibited layer

d) To help the various resin layers stick together

RQ

5.) The curing light requires repair if:

a) It causes a slower set of a dark-color composite.

b) It has not been tested.

c) A 2-mm-thick piece of composite does not cure through the bottom at the recommended exposure time.

d) The light appears blue.

a) It causes a slower set of a dark-color composite.

b) It has not been tested.

c) A 2-mm-thick piece of composite does not cure through the bottom at the recommended exposure time.

d) The light appears blue.

RQ

6.) Polymerization shrinkage of a composite:

a) Is cause for alarm

b) Is greater than 10% of the volume

c) Can be minimized by placing and curing a series of small increments

d) Has no effect on the final restoration

a) Is cause for alarm

b) Is greater than 10% of the volume

c) Can be minimized by placing and curing a series of small increments

d) Has no effect on the final restoration

RQ

7.) Fillers are composed of all of the following except one. Which one is this exception?

a) Quartz

b) Resin

c) Silica

d) Glass

a) Quartz

b) Resin

c) Silica

d) Glass

RQ

8.) Which one of the following statements about a coupling agent is false?

a) It minimizes the loss of filler particles.

b) It reduces wear.

c) It prevents filler from sticking to the resin.

d) It is made of silane.

a) It minimizes the loss of filler particles.

b) It reduces wear.

c) It prevents filler from sticking to the resin.

d) It is made of silane.

RQ

9.) All of the following will increase the wear of a composite restoration except one. Which one is this exception?

a) Use of large filler particles

b) Incompletely curing the composite

c) Use of small amount of filler particles

d) Saliva contamination of the etched enamel

a) Use of large filler particles

b) Incompletely curing the composite

c) Use of small amount of filler particles

d) Saliva contamination of the etched enamel

RQ

10.) Which one of the following types of composites is the weakest and should not be used in stress-bearing tooth surfaces?

a) Hybrid

b) Microfill

c) Nanofill

d) Nanohybrid

a) Hybrid

b) Microfill

c) Nanofill

d) Nanohybrid

RQ

11.) Which one of the following composites has the lowest viscosity and can be delivered from a syringe directly into a cavity preparation?

a) Microcomposite

b) Nanocomposite

c) Flowable composite

d) Nanohybrid composite

a) Microcomposite

b) Nanocomposite

c) Flowable composite

d) Nanohybrid composite

RQ

12.) Heavily filling the resin matrix with nanosized fillers particles will reduce which one of the following?

a) Curing time

b) Strength of the material

c) The esthetics

d) Polymerization shrinkage

a) Curing time

b) Strength of the material

c) The esthetics

d) Polymerization shrinkage

RQ

13.) Which one of the following composites is most difficult to polish to a high shine?

a) Macrofill

b) Microhybrid

c) Nanohybrid

d) Hybrid

a) Macrofill

b) Microhybrid

c) Nanohybrid

d) Hybrid

RQ

14.) Which one of the following types of composites generally will shrink the most when polymerized?

a) Bulk-fill composite

b) Microhybrid

c) Flowable composite

d) Nanocomposite

a) Bulk-fill composite

b) Microhybrid

c) Flowable composite

d) Nanocomposite

RQ

15.) What is the major shortcoming of chemical cured composites?

a) They are the weakest of the composites.

b) They cannot be polished.

c) They generate excessive heat when they cure.

d) They have limited working time.

a) They are the weakest of the composites.

b) They cannot be polished.

c) They generate excessive heat when they cure.

d) They have limited working time.

RQ

16.) Which one of the following is a drawback of bulk-fill composites?

a) Difficult to cure a 4-mm increment to its entire thickness

b) Excessive polymerization shrinkage

c) Color is too opaque

d) Weaker than other posterior composites

a) Difficult to cure a 4-mm increment to its entire thickness

b) Excessive polymerization shrinkage

c) Color is too opaque

d) Weaker than other posterior composites

RQ

17.) Common effects of polymerization shrinkage of composites may include all of the following except one. Which one is this exception?

a) Microleakage

b) Death of the pulp

c) Microcracking of enamel causing white lines around the margins

d) Postoperative sensitivity

a) Microleakage

b) Death of the pulp

c) Microcracking of enamel causing white lines around the margins

d) Postoperative sensitivity

RQ

18.) Methods used to minimize polymerization shrinkage include all of the following except one. Which one is this exception?

a) Cure the composite rapidly with a high-intensity light

b) Use prepolymerized filler clusters

c) Use composite with a high filler content

d) Place composite using small increments

a) Cure the composite rapidly with a high-intensity light

b) Use prepolymerized filler clusters

c) Use composite with a high filler content

d) Place composite using small increments

RQ

19.) All of the following circumstances may require a longer curing time for a composite except one. Which one is this exception?

a) Use of an opaque shade

b) Use of increments of composite greater than 2mm

c) Placement of the curing light tip 6 to 8mm from the composite

d) Composite placed in a class III preparation on no. 8 mesial

a) Use of an opaque shade

b) Use of increments of composite greater than 2mm

c) Placement of the curing light tip 6 to 8mm from the composite

d) Composite placed in a class III preparation on no. 8 mesial

RQ

20.) What allows a new increment of composite to stick to the previously cured increment?

a) Mechanical retention

b) Chemical resin-to-resin bond

c) Addition of a bonding agent to the cured increment

d) The silane coupling agent

a) Mechanical retention

b) Chemical resin-to-resin bond

c) Addition of a bonding agent to the cured increment

d) The silane coupling agent

RQ
21.) The function of the wedge placed interproximally with a class Il preparation includes all of the following except one. Which one is this exception?

a) Stop bleeding

b) Create slight separation of the teeth

c) Seal the matrix band against the tooth at the gingival margin

d) Protect the gingival papilla during cavity preparation

a) Stop bleeding

b) Create slight separation of the teeth

c) Seal the matrix band against the tooth at the gingival margin

d) Protect the gingival papilla during cavity preparation