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Operative II > Current Adhesives and Composite Bonding > Flashcards

Current Adhesives and Composite Bonding Flashcards

1
Q

What is cohesion?

A

attraction between similar molecules or atoms

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2
Q

What is adhesion?

A

attraction between unlike molecules, attraction between two contacting surfaces

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3
Q

What is the adherend?

A

material bonded to another material by means of an adhesive

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4
Q

What is adhesive?

A

substance that promotes adhesion

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5
Q

What is adhesive bonding?

A

joining two materials by means of an adhesive

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6
Q

Is a physical bond weak or strong?

A

very weak

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7
Q

Is a chemical bond strong or weak?

A

Very limited with dissimilar materials

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8
Q

How does a mechanical bond work?

A

◦ Interlocking
◦ Adhesive interlocks into surface irregularities
◦ THIS IS THE DENTAL ADHESION MECHANISM

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9
Q

What is the main dental adhesion mechanism?

A

mechanical

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10
Q

What does microscopic intimate interface do to interlocking?

A

improves interlocking

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11
Q

What is surface wetting?

A

the ability of a liquid to maintain intermolecular contact with a solid surface

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12
Q

What does improved surface wetting do to surface energy?

A

increases surface energy

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13
Q

How do you increase the surface area?

A

◦ INCREASE SURFACE AVAILABLE FOR BONDING
◦ BY ETCHING
◦ Roughened surface (diamond bur for bevels)
◦ Etching transforms smooth enamel into an IRREGULAR surface

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14
Q

What is the dental adhesion of enamel?

A

~25-30 MPa
- very predictable

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15
Q

What is the dental adhesion of dentin?

A

◦ Bond strengths vary
- more challenging

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16
Q

What is the type I enamel etching?

A
  • “honeycomb”
  • from dissolution of prism (enamel rod) CORES
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17
Q

What is the type II enamel etching?

A
  • “cobblestone”
  • from dissolution of prism (enamel rod) PERIPHERIES
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18
Q

Where are type I and type II enamel etching areas found?

A

occlusal and middle thirds of teeth

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19
Q

What areas of enamel etching are the best bonds?

A

TYPE I AND II

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20
Q

What is the type III enamel etching?

A

combination of I and II

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21
Q

What is the type IV enamel etching?

A

pitted

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22
Q

What is the type V enamel etching?

A

asprismatic (flat and smooth)

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23
Q

What is acid etching enamel?

A
  • chemical “drilling”
  • creates porous layer 5-50 microns deep
  • called conditioner
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24
Q

___% phosphoric acid is most effective for enamel retention

A

30-40%

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25
Q

How much enamel does acid etching remove?

A

10 microns

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26
Q

How do you apply acid etching enamel?

A

RINSE with water for 10 seconds after etching
◦ To remove acid and leave enamel surface clean for bonding

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27
Q

Etching raises the surface free energy to _______ the surface tension of bonding material

A

EXCEED

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28
Q

Etching produces spaces where resin can penetrate to form…

A

resin tags

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29
Q

After etching you should apply bond agent resin why?

A
  • low viscosity so it can flow into microporosities
  • polymerizes to micromechanical bond
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30
Q

What is the etch-and-rinse (total etch) system?

A
  • Etch separately
  • Prime
  • Bond
  • Or Prime + Bond combined
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31
Q

What is the self-etch system?

A
  • No phosphoric acid-etch step
  • Acid part of the primer or primer/bond agent
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32
Q

What is the 3-step (2-bottle) total etch system?

A

a.Etchant
b.Primer
c.Bond agent
(scotch bond multipurpose)

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33
Q

What is the 2-step (1-bottle) total etch system?

A

a.Etchant
b.Primer and bond agent combined
(Prime and Bond NT, PQ 1, Peak,
Optibond Solo Plus)

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34
Q

What is the 2 step self-etching bonding system?

A
  • acidic primer & bonding agent
    ◦ Acidic primer partially dissolves smear layer, allows penetration of bond resin
    ◦ Clearfil SE Bond; Clearfil Liner Bond 2V
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35
Q

What is the 1 step self-etching bonding system?

A

– most variable/ least predictable
◦ Acidic primer and bond resin, one solution (Many require mixing)
◦ Examples: Xeno, i-Bond, Bond Force (no mix)

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36
Q

What are the advantages of the rinse and etch system?

A

◦ More predictable, stronger bond
◦ Enamel adequately prepared

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37
Q

What are the disadvantages of the rinse and etch system?

A

◦ Collagen collapse is possible
◦ Etched zone is often deeper than hybrid layer
◦ Exposed demineralized, collagen fibrils
◦ Post-operative sensitivity

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38
Q

What are the advantages of self-etch systems?

A

◦ No separate etch: overdried, collapsed demineralized collagen not a problem
◦ Etched zone and hybrid layer comparable width; however, some exposed collagen
◦ Low post-operative sensitivity
◦ Time efficiency

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39
Q

What are the disadvantages of self-etch systems?

A

◦ Not compatible with self-cure, dual-cure composite
◦ Acidic monomers, low pH, “kills” the basic amine activator
◦ Will not etch unprepared enamel
◦ Self-etch primer systems

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40
Q

What are the disadvantages of the self-etch adhesives (all-in-one)?

A

◦ Lower bond strength
◦ Long-term breakdown?
◦ Collagen degradation over time

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41
Q

What can you use with universal adhesives?

A

Can be used in total etch, self-etch or selective-etch mode (etch
enamel only with phosphoric acid)

  • we use at UMKC
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42
Q

What is the chemistry game changer of universal adhesives?

A

10-MDP
◦ Methacryloyoxy-decyl-dihydrogen-phosphate (10-MDP)

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43
Q

What is the mechanism of action of a universal adhesive?

A

A monomer that chemically interacts via ionic bonding to calcium in hydroxyapatite

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44
Q

What is the monomer for universal adhesives?

A

a phosphate ester

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45
Q

Should you directly etch the pulp?

A

nope

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46
Q

Why do we now use a total etch technique of etching enamel and dentin?

A

Etchant interacts with superficial dentin and there is no pulpal damage

47
Q

The bond to dentin collagen is influenced by…

A

Matrix metalloproteinases (MMPs)
* collagen enzymes that metabolize unhybridized collagen

48
Q

___________ inhibits MMP (matrix metalloproteinases) activation

A

Chlorhexidine

49
Q

What is consepsis (ultradent)?

A

◦ 2% Chlorhexidine Antibacterial Solution
◦ Applied after acid etching

50
Q

What can cause an adverse pulp reaction if using adhesive on dentin?

A

Adverse pulp reaction comes primarily from bacteria remaining in or penetrating the preparation

51
Q

What are the requirements for clinical success of bonding?

A
  1. Knowledge of substrate
  2. Good cavity preparation and margins
  3. Rubber dam and matrix/wedge
  4. Correct use of the bonding agent
  5. Bond agent compatible with resin composite
52
Q

What region of the tooth has a higher bond strength: superficial or deep?

A

superficial

53
Q

What region of the tooth has a higher bond strength: flat or box?

A

flat surfaces

54
Q

What can make the bond strengths to dentin vary?

A

-Region of tooth
-Flat surfaces higher than box cavities
-C-factor
-Adhesive system used
-Thickness of increment of composite resin
-Operator
-Intrinsic wetness of tooth
-Dryness vs wetness

55
Q

What is the best place to adhere to the enamel?

A

Incisal third and middle third enamel

56
Q

What is wrong with the adhesion near the cervical enamel?

A

◦ Shorter and fewer enamel tags (Compared to middle and incisal thirds)
◦ Less prism delineation

57
Q

Prism delineation is found in cervical third of ___% of teeth

A

70%

58
Q

What do bevels and adhesion do in class II preps?

A

Reduce microleakage at cervical and ascending walls in Class II preparations

59
Q

When is a bevel gingival floor of prep necessary?

A

enamel

60
Q

What does beveling the enamel do?

A

◦ Exposes ends of enamel rods
◦ Reveals prismatic enamel

61
Q

What bur should you use to bevel the gingival floor?

A

7902 bur

62
Q

When would you not bevel the gingival floor?

A

Deep preparations
◦ So little enamel remains that a bevel would remove it all OR
◦ Gingival floor is on cementum or dentin

63
Q

The goal of adhesive dentistry with composite resin in enamel is…

A
  • interlocking with enamel rods
64
Q

The goal of adhesive dentistry with composite resin in dentin is…

A
  • interlocking with dentin collagen
65
Q

What are the percentages and components of enamel?

A

◦ 95-98% inorganic matter by weight
◦ 90-92% hydroxyapatite by volume
◦ 1-2% organic matter by weight
◦ 4% water weight

66
Q

Where can you find perpendicular oriented enamel?

A

◦ Cavosurface margins of class I preparations
◦ Bevels of class II preparations
◦ ENDS of enamel rods

67
Q

Where can you find parallel oriented enamel?

A

◦ Internal walls of occlusal preparations
◦ Gingival floor of box of class II preparations (see bevelling)
◦ SIDES of enamel rods

68
Q

What are resin tags interlock?

A

Macro and micro tags into surface irregularities

69
Q

What are the MPa of the enamel-adhesive composite bond?

A

20-25MPa

70
Q

What are the percentage components of dentin?

A

◦ 55% mineral by volume
◦ 30% collagen
◦ 15% water

71
Q

What are the different parts of the dentin?

A

Tubules
◦ Fluid filled
Peritubular Dentin
◦ Very Inorganic
Intertubular dentin
◦ Very ORGANIC
◦ Collagen rich

72
Q

What part of the dentin is inorganic?

A

Peritubular Dentin

73
Q

What part of the dentin is organic and collagen rich?

A

Intertubular dentin

74
Q

What is the diameter of dentin tubules at the DEJ?

A

0.5 µm

75
Q

What is the diameter of dentin tubules at the pulp?

A

2.5 µm

76
Q

As the dentin goes deeper the tubules are…

A

wider and more of them
- more fluid

77
Q

As the dentin goes deeper there is ______ intertubular dentin

A

less

78
Q

What is the smear layer?

A

mixture of tooth debris, often contaminated with saliva, blood cells, and bacteria

79
Q

Should you bond to the smear layer?

A

NO
- remove smear layer with acid etch
- bond strength of smear layer is 7.4 MPa

80
Q

What is the hybrid layer?

A

intermingled layer of collagen and resin

81
Q

What is the problem with forming the hybrid layer?

A

Must be the perfect balance
◦ Avoid OVERetching
◦ Avoid OVERdrying
◦ Avoid UNDERdrying

82
Q

What are the steps to form the hybrid layer?

A

1.Acid Etch 15 seconds dentin
2.Wash and LIGHTLY dry = Hydroxyapatite removed, water remains to support collagen fibers
3.Apply primer
4. Apply adhesive
5. Light cure

83
Q

What happens when the hybrid layer forms?

A

upon light curing, the unfilled resin sets within the collagen fibril network

84
Q

What are some problems with forming the hybrid layer?

A
  • overetching
  • overdrying
  • underdrying
85
Q

What happens to the hybrid layer if you overetch?

A

results in underfilled restorations

-Demineralized zone is too thick
-Primer can not infiltrate far enough
-Leaves unprotected layer
subject to degradation
-leads to premature bond failure
-leads to failure over time due to hydrolysis of uninfilitrated collagen

86
Q

What happens to the hybrid layer if you overdry?

A

results in lower bond strengths

-Collagen collapses
-lower bond strength

87
Q

What happens to the hybrid layer if you underdry?

A

results in collagen that is too wet
◦ Excess water
◦ Poor hybrid layer formation
◦ Resin unable to infiltrate intertubular dentin
◦ “blister spaces” where primer and adhesive separate

88
Q

Which type of bonding system has the self-etching primers?

A

self-etching primers

89
Q

What type of bonding system do we primarily use in lab and clinic?

A

Universal Adhesives

90
Q

What are the disadvantages of bonding systems?

A
  • Too many steps
  • Insufficient penetration of smear layer
  • Delicate treatment of dentin necessary
91
Q

What is the etchant for bonding system?

A

Phosphoric acid gel (30-40%)

92
Q

What is the primer for bonding system?

A

◦ HYDROPHILIC monomers in HEMA solvent
◦ Acetone, ethanol/water, water

93
Q

What is the adhesive bonding resin/agent for bonding system?

A

◦ HYDROPHOBIC dimethacrylate monomers (BisGMA)
◦ Initiators and Activators
◦ Camphorquinone in light activated systems
◦ Benzoyl Peroxide (BPO) Tertiary amine in chemical and dual cure systems

94
Q

What is the adhesive bonding resin agent for light activated systems?

A

Camphorquinone

95
Q

What is the adhesive bonding resin agent for chemical and dual cure systems?

A

Benzoyl Peroxide (BPO) Tertiary amine

96
Q

What are the fillers for bonding systems?

A

Most unfilled resins, some 0.5-40 % by weight

97
Q

What is the polymerization process?

A

Adhesive/primer monomers–> polymers
◦ Chemical reaction

98
Q

What is the activator in the polymerization process?

A

light or chemical

  • blue light
  • benzoyl peroxide
99
Q

What is the polymerization process using light?

A

◦ Blue light (~470-nm)
◦ Camphorquinone→free radical→polymerization reaction

100
Q

What is the polymerization process using chemical?

A

◦ Chemical (tertiary amine)
◦ Benzoyl peroxide (initiator)→free radical→polymerization reaction

101
Q

What are the steps in the bonding process?

A

Step 1. Acid etch
◦ 20 seconds for enamel
◦ 15 seconds for dentin
Step 2. Rinse
◦ 10 seconds
◦ GENTLY dry- enamel should be dry, dentin should be slightly moist
Step 3. Apply Primer- not with Adhese Universal
Step 4. Apply Bond
Step 5. Light cure
Step 6. Place composite incrementally

102
Q

How long should you etch dentin and enamel?

A

◦ Dentin- 15 seconds at MOST
◦ Enamel- 20 seconds

103
Q

What does acid etch do?

A

◦ Removes smear layer
◦ Denatured collagen, hydroxyapatite crystals, debris from cutting tooth

104
Q

How much should you dry enamel and dentin during the acid etch?

A

enamel - dry
dentin - slightly moist

105
Q

What does blue light do in the polymerization reaction?

A

activates

106
Q

What does camphorquinone do in the polymerization reaction?

A

initiates

107
Q

Primary dentin bond mechanism is from _______ LAYER

A

HYBRID

108
Q

What is the hybrid layer?

A

micromechanical interlocking of resin with demineralized
collagen

109
Q

What are the factors that affect the bond to dentin?

A
  • cavity depth
  • caries
  • moist vs dry dentin
  • rubber dam
110
Q

What helps form a better bond to dentin: moist or dry dentin?

A

moist

111
Q

What helps form a better bond to dentin: superficial dentin or deep dentin?

A

superficial dentin

112
Q

Do caries increase or decrease the ability to bond to dentin?

A

decrease

113
Q

What happens if the dentin is too wet when you try to bond?

A

◦ Resin doesn’t penetrate well
◦ Decreased bond strength

114
Q

What happens if the dentin is too dry when you try to bond?

A

◦ Resin cannot penetrate
◦ Poor hybrid layer
◦ Decreased bond strength

Operative II (11 decks)

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