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Direct Restoration > Principles of Composite Restorations - Sturdevant's Ch 8 and Ch 9 > Flashcards

Principles of Composite Restorations - Sturdevant's Ch 8 and Ch 9 Flashcards

1
Q

List the 7 advantages of composites:

A
  1. esthetics
  2. Conservative in tooth structure removal
  3. Less complex when preparing the tooth
  4. Insulating (low thermal conductivity)
  5. Used universally
  6. Bonds to tooth structure
  7. repairable
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2
Q

List the 5 disadvantages of composites:

A
  1. May have a gap formation (on the root surface or improper insertion)
  2. More difficult, tim-consuming, and costly as compared to amalgams (multiple steps & polishing)
  3. Technique is more important
  4. May exhibit greater occlusal wear
  5. Has a higher LCTE (linear coefficient of thermal expansion) = results in potential marginal percolation
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3
Q

If a void or defect is detected before finished, do you have to start over?

A

No, more composite can be added directly to the void IF the composite has NOT been contoured.

The materials bond because the void area has an oxygen-inhibited surface layer that permits composite additions.

Contouring removes this oxygen-inhibited layer and thus the material would need to be re-etched before placing more composite.

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4
Q

Define over-contouring the restoration

A

The contours are too high (think: over = higher). The contours created are too large or too occlusal.

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5
Q

Define under-contouring the restoration

A

The contours are smaller than ideal (think under = small). The contours created are too small or too gingival.

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6
Q

What does RMGI stand for?

A

Resin Modified Glass Ionomer!

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7
Q

What is flash?

A

The thin portion of composite extending beyond the margin.

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8
Q

Overcontour

A

Too much has been added to the restoration

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9
Q

Overflow

A

The same as flash: composite that has extended beyond the margins.

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10
Q

Undercontour

A

Too little has been added to the restoration, so there is a little divot.

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11
Q

What is a common polymeric matrix component for composites?

A

Bis-GMA

Als0:
UDMA
TEG-DMA
Bis-EMA

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12
Q

What are common filler particles for composites?

A

Glass: barium or borosilicate

Zirconium oxide, aluminum oxide, silicone dioxide

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13
Q

What is used as a coupling agent in composites?

A

Silane - an adhesion filler to the matrix

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14
Q

What is used as the initiator for composites?

A

Camphoroquinone - a photoinitiator

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15
Q

Is a composite’s thermal expansion greater or lower than tooth structure’s?

A

Greater! Composite has a thermal expansion 2-6 times greater than tooth structure.

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16
Q

What size of filler are macrofill composites?

A

8 micrometers

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17
Q

What size of filler for microfill composites?

A

0.01 - 0.04 micrometers

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18
Q

What size of filler do hybrid composites contain?

A

Can have microhybrid or nanohybrid.

Range from 0.4 - 1 micrometers

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19
Q

What size of filler for nanofill composites?

A

1 - 100 nanometers

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20
Q

What are the general steps for dental bonding?

A
  1. Conditioner (etching)
  2. Primer
  3. Adhesive
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21
Q

What is the conditioner used for dental bonding?

A

The etching material.

An acid (phosphoric) that removes inorganic material.

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22
Q

What is the primer used for dental bonding?

A

A hydrophilic monomer

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23
Q

What is the adhesive used for dental bonding?

A

A hydrophobic low viscosity resin.

Creates micromechanical retention and is light cured.

24
Q

How does OptiBond Solo Plus in our clinic work for dental composite bonding?

A

The primer and adhesive are combined into one step, so it is just a 2-step etch and rinse process.

  1. Conditioner
  2. Primer + adhesive
25
Q

When are retention grooves necessary?

A

Mainly just in Sim Clinic because we do not use bonding to the plastic teeth.

26
Q

What are the different types of initiators that may be used for different composites?

A

Initiators create free radicals:

Heat
Chemical
UV Light
Visible Blue Light

27
Q

What is irradiance?

A

Power per area (mW/cm^2)

Basically, how intense and focused the light is.

28
Q

What is collimation?

A

The dispersion of the light. A “good” light has good collimation - it is focused and not dispersed.

29
Q

How long do we cure our composite for?

A

At lease 20 seconds.

30
Q

What are 3 main ways to compensate polymerization shrinkage?

A
  1. Incremental placement (1 - 2 mm increments)
  2. Adequate bonding technique
  3. Placement of a liner
31
Q

What is the C-factor?

A

The configuration factor.

Bonded Surfaces/#Unbonded Surfaces

Low C factor = low risk of contraction

High C factor = high risk of contraction

32
Q

What is the C-factor for a Class I?

A

bonded surfaces = 5

unbonded surfaces = 1

C-factor = 5 = high risk of contraction

33
Q

What components are necessary to form a composite material?

A

Polymeric matrix
Filler particles
Coupling Agent
Initiator

34
Q

What are the mechanical characteristics of composites (in terms of wear, toughness, and elastic)?

A

Pretty good wear resistance (though amalgam is better)

Low fracture toughness as compared to metallic

High degree of elastic deformation

35
Q

Is there any shrinkage with composites?

A

Yep: 2.6% - 7.1%

36
Q

What is the coefficient of thermal expansion of composite as compared to enamel?

A

Composite thermal expansion is 2 - 6 times greater than enamel.

37
Q

What are the three classifications of composites?

A

Conventional - more filler, better mechanical properties

Flowable - less filler, less strong

Packable - not recommended.

38
Q

What are advantages and disadvantages of microfill composites? Give a brand example.

A

Pro:
Excellent polish
Excellent longevity
Excellent handling

Cons:
Weaker mechanical properties
Not for stress-bearing restorations

Types: Durafil VS (Kulzer)
Renamel (Cosmodent)

39
Q

What are advantages and disadvantages of hybrid composites? Give a brand example.

A 
Pro:
Good polishing
Good handling
Good physical properties
Good range of opacities
Excellent longevity

Types:
Premise (Kerr) - microhybrid
Esthet-X HD (Dentsply) - nanohybrid

40
Q

What are advantages and disadvantages of nanofill composites? Give a brand example.

A 
Pros:
Excellent, long lasting polish
Good handling
Excellent mechanical properites
Good for incisal edges
Highly translucent
Good opacity
Excellent longevity
Types: Fitek Supreme Plus (3M)
Estelite Omega (Tokuyama)
41
Q

What can go wrong as a composite restoration is completed?

A
  1. Not curing long enough
  2. Blood or saliva contamination
  3. Desiccation - creates collapsed collagen fibers and poor bonding

Poor bonding can cause post-op sensitivity

42
Q

How is OptiBond Solo Plus system applied - the conditioner?

A

Recall: 1st use the conditioner, rinse, and 2nd use the primer and adhesive combined.

The conditioner:

  1. Can be used on both dentin & enamel
  2. Surfaces must be dry
  3. Do not apply for longer than 15 minutes for dentin
  4. Rinse thoroughly with water
  5. Leave the dentin surface damp
43
Q

How is OptiBond Solo Plus applied - the primer/adhesive combo?

A

The primer/adhesive combo:

  1. Apply thin coat
  2. “Air thin” the solution for 3 seconds to spread and avoid any pooling
  3. Light cure for 20 seconds
44
Q

For polymerization, if the initiator is heat, what is the chemical reaction?

A

Benzoyl peroxide + heat = free radical

45
Q

For polymerization, if the initiator is chemical, what is the chemical reaction?

A

Benzoyl peroxide + tertiary amine = free radical

46
Q

For polymerization, if the initiator is UV light, what is the chemical reaction?

A

Benzoin methyl ether + 365nm UV light = free radical

47
Q

For polymerization, if the initiator is visible blue light, what is the chemical reaction?

A

Camphoroquinone + tertiary amine + 468nm blue light = free radical

48
Q

When using the Tungsten Halogen (QTH) to apply blue light for polymerization, how long must it be applied?

A

20 - 40 seconds (500 - 1000 mW/cm2)

49
Q

When using the High Intensity TH to apply blue light for polymerization, how long must it be applied?

A

20 seconds (1200 mW/cm2)

50
Q

When using the Plasma Arc Curing (PAC) to apply blue light for polymerization, how long must it be applied?

A

10 - 20 seconds (1600 - 2000 mW/cm2)

51
Q

When using the LED to apply blue light for polymerization, how long must it be applied?

A

10 - 40 seconds (500 - 1600 mW/cm2)

52
Q

What type of curing light do we use in clinic?

A

LED curing light
Ultradent - VALO Curing Light
20 second cure time

53
Q

What is the range of wavelengths for blue light?

A

450 - 500 nm

54
Q

Does it matter how far the light is held from the composite resin as it cures?

A

Yes. The times were calculated based on the light being 1 - 1.5 mm from the composite resin.

55
Q

Blue light is pretty. Can we stare at it?

A

No! Bad for your eyes - cumulative retinal injury.

Direct Restoration (6 decks)

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