AdhesionAdhesion , L. adhaerere
ad (to), haerere (stick)
___- substance that we are ‘sticking’ to
enamel or dentin
____- the bonding agent
AdhesionAdhesion , L. adhaerere
ad (to), haerere (stick)
adherend- substance that we are ‘sticking’ to
enamel or dentin
ahherent- the bonding agent
Adhesive System
The material that when applied to surfaces, can___ ___ ____r, resist ____, and transmit ____ across the bond.
Doesn’t require a ___ exchange to form an adhesive bond
Adhesive System
The material that when applied to surfaces, can join them together, resist separation, and transmit loads across the bond.
Doesn’t require a chemical exchange to form an adhesive bond
Advantages of Adhesion
- Whenever you use composite material and you set it up with a light, it will shrink
- Help offset ___ ____
- Reduce ___ ___
- S____
- S____
- C____
- Reduce ___ ___
- Adhesion
- Conservation of ___ ___
- Internal ___
- ____ restorations
Advantages of Adhesion
Whenever you use composite material and you set it up with a light, it will shrink
Help offset polymerization shrinkage
Reduce marginal leakage
Staining
Sensitivity
Caries
Adhesion
Conservation of tooth structure
Internal splinting
Esthetic restorations
Surface Wetting
An important concept for adhesion
If a tooth surface is contaminated with ___ or __ ___r (____ after you cut on a tooth) it will ___ the wettability of the material
The better we can wet the material the____ adhesion we will get
Contact angle should ____ with a good dental adhesive that provides good wettability
Enamel has a ___ surface E
Enamel is ___ ___ ___ to than dentin
It has a higher surface E so a ____ contact angle with adhesives. We get ____ wetting of material and better adhesion
Tooth surface contamination
- ___, ___ ____
Clean surface
- ____ surface energy
- ____ contact angle
Surface Wetting
An important concept for adhesion
If a tooth surface is contaminated with saliva or smear layer (debri after you cut on a tooth) it will decrease the wettability of the material
The better we can wet the material the better adhesion we will get
Contact angle should decrease with a good dental adhesive that provides good wettability
Enamel has a high surface E
Enamel is easier to bond to then dentin
It has a higher surface E so a lower contact angle with adhesives. We get better wetting of material and better adhesion
Tooth surface contamination
saliva, smear layer
Clean surface
Increase surface energy
Decrease contact angle
Variations in Tooth Structure
Variations in Tooth Structure
- Enamel
- ***more ___ ____***
- more ____ structure
- higher____content
- ____ surface energy
- This ___ wetability
- Dentin
- ___ predictable bonding
- higher ____
- higher___ content
Variations in Tooth Structure
Enamel
***more predictable bonding***
more homogeneous structure
higher inorganic content
higher surface energy
This improves wetability
Dentin
less predictable bonding
higher variability
higher organic content
- Enamel Composition
- Primarily inorganic
- Made of _____
- Small amt of organic
- ___% water
- Dentin Composition
- Theres__ __ ___water in dentin
- We need dental adhesives that are ____!There will be a component in the adhesive that will deal with the water
- Solvent like acetone to chase the water or Alcohol
Enamel CompositionPrimarily inorganic
Hydroxyapatite
Small amt of inorganic
12% water
Dentin Composition
Theres a lot more water in dentin
We need dental adhesives that are hydrophilic!There will be a component in the adhesive that will deal with the water
Solvent like acetone to chase the water or Alcohol
- Basic Mechanism of Adhesion (resin-based)
- Exchange process
- replacement of ____ from ___ ___
- by ___ ____
- ____ly ____ed
- Primarily ___
- Retentive ____
- Velcro is loop and hook system: Similar to bonding to dentin
- Fuzzy: ___
- This is the ___ with ___
- Loops
- This is like our ___
- Not a chemical bond!
- It is adhesion
- Exchange process
Basic Mechanism of Adhesion (resin-based)Exchange processreplacement of minerals
from hard tissue
by resin monomers
micromechanically interlocked
Primarily mechanical
Retentive interlocking
Velcro is loop and hook system: Similar to bonding to dentinFuzzy: Hooks
This is the Dentin with collagen
Loops
This is like our adhesive
Not a chemical bond!
It is adhesion
Enamel Bonding
- Developed by Buonocore-1955
- Etching
- various ___
- traditionally ___ ___
- creates ____
- ____ microns deep
- ___ surface energy
- ____ wettability
- Traditionally what we use today is phosphoric acid
- This creates micropores in the enamel
- various ___
Enamel Bonding
Developed by Buonocore-1955
Etchingvarious acids
traditionally phosphoric acid
creates micropores
5 – 50 microns deep
increases surface energy
increases wettability
Traditionally what we use today is phosphoric acid
This creates micropores in the enamel
Enamel Bonding
- We can use ___-viscosity monomers
- examples
- ____
- Most popular one
- Found in adhesives and composites
- ___
- ___
- ___
- Predictably ___ bond strengths
- > __ MPa
- ____
- We don’t have water to deal with so we can use monomers that are ____
- Even though they are hydrophobic, they wet the surface___
Enamel BondingWe can use Low-viscosity monomersexamplesBis-GMA
Most popular one
Found in adhesives and composites
UDMA
TEGDMA
HEMA
Predictably high bond strengths
> 20 MPa
We don’t have water to deal with so we can use monomers that are hydrophobic
Even though they are hydrophobic, they wet the surface well
Tubule Composition
- _____ dentin
- ____ tubule
- _____ mineral
- ___ dentin
- ____ tubules
- ____ mineral
- Like the ____ for Velcro
- That’s where ____ is taking place
- ____ process
- Dentinal ____
- Dentin is a different ballgame.
- All the research for adhesives is to help us find ways to bind more predictably and strongly to dentin
- If restoration fails, it wont be bc enamel bond failed, it will be bc dentin bond failed
- Misconception: People think our adhesion occurs bc it flows down into tubules
- That is not the case
- Adhesion is primarily to the intertubular dentin
- Not just plug that we filling up
- More like Velcro that we ___ ___
Tubule CompositionPeritubular dentin
surrounds tubule
hypermineralized
Intertubular dentin
between tubules
less mineralized
Like the fuzz for Velcro
That’s where adhesion is taking place
Odontoblastic process
Dentinal fluid
Dentin is a different ballgame.
All the research for adhesives is to help us find ways to bind more predictably and strongly to dentin
If restoration fails, it wont be bc enamel bond failed, it will be bc dentin bond failed
Misconception: People think our adhesion occurs bc it flows down into tubules
That is not the case
Adhesion is primarily to the intertubular dentin
Not just plug that we filling up
More like Velcro that we adhering to
Tubule Composition
- As you progress deeper into tooth____ and ____ of tubules changes
- As you move down,
- Tubules get ___
- There is ___ of them
- So there is___ intertubular dentin surface to bond to
- As you get deeper into the tooth, bonding to dentin is ___ predictable
Tubule Composition
As you progress deeper into tooth number and diameter of tubules changes
As you move down,
Tubules get larger
There is more of them
So there is less intertubular dentin surface to bond to
As you get deeper into the tooth, bonding to dentin is less predictable
Changes in Dentin Structure
- ____
- normal ___
- As we age, dentin becomes more sclerotic
- More ___ and ____
- More difficult for adhesins to ____ the collagen network in the intertubular dentin
- ____
- ____
- ____
- caries
- dental procedures
- Mineral: ______
- ___ receptive to bonding
- Something that we do to try to improve the predictability of sclerotic repair to dentin is to increase our __ ___
- (We talked about phosphoric acid, which is the acid that we treat enamel with to increase the surface. We use acids to prepare the dentin also.)
- If you have hypermineralized intertubular dentin, the acid will ___ th e____ and increase the ____ to penetrate thru
- If its sclerotic, you may have to increase the contact time of the acid
- Etch= add acid to tooth to prepare it to receive the adhesive
- Etchet: Acid
Changes in Dentin StructureScleroticnormal aging
As we age, dentin becomes more sclerotic
More Callused and dense
More difficult for adhesins to penetrate the collagen network in the intertubular dentin
abrasion
erosion
Reparative
caries
dental procedures
Hypermineralization
Less receptive to bonding
Something that we do to try to improve the predictability of sclerotic repair to dentin is to increase our etch time
(We talked about phosphoric acid, which is the acid that we treat enamel with to increase the surface. We use acids to prepare the dentin also.)
If you have hypermineralized intertubular dentin, the acid will dissolve the mineral and increase the microspace to penetrate thru
If its sclerotic, you may have to increase the contact time of the acid
Etch= add acid to tooth to prepare it to receive the adhesive
Etchet: Acid
- Smear Layer
- Produced by ____
- Composition
- __ ___ ___
- ____
- ____ dentin permeability
- ___%
- When we prepare a tooth structure, we create a smear layer
- Cut dentin debri mixed with bacteria
- This is removed when we apply our ______to the dentin
- Typically ___ on enamel
- More so on dentin where there is high amount of ___ material (collagen)
- When we remove the smear layer, now you have a __ ___
- Debris has gone down into tubule
- When we add acid, it ____ the smear plug. You are conditioning it, cleaning it
- Now all tubules are ___ and the intertubular dentin is___ of debri and ready to receive our ____
Smear Layer
Produced by instrumentation
Composition
cut dentin debris
bacteria
Reduces dentin permeability
86%
When we prepare a tooth structure, we create a smear layer
Cut dentin debri mixed with bacteria
This is removed when we apply our acid/etchet to the dentin
Typically not on enamel
More so on dentin where there is high amount of organic material (collagen)
When we remove the smear layer, now you have a smear plug
Debris has gone down into tubule
When we add acid, it dissolves the smear plug. You are conditioning it, cleaning it
Now all tubules are open and the intertubular dentin is clean of debri and ready to receive our adhesive
Dentinal Wetness
- Increases with
- ___ ___
- ___ of ___ ___
- Historically, more ___ to bond
- As we increase dentin depth, it becomes more difficult to bond to because there is an increase in dentinal wetness.
Dentinal WetnessIncreases
Dentinal depth
Removal of smear layer
Historically, more difficult to bond
As we increase dentin depth, it becomes more difficult to bond to because there is an increase in dentinal wetness.
Dentin Wetness: Etch & Rinse
- After conditioning dentin
- dentin must be ___
- prevent___ ____
- dentin must be ___
- Too little water
- Collagen matrix will ____
- Intertubular dentin
- Fuzzy Velcro
- They are hydrated (like spaghetti in a bowl of water)
- Take out water and fibrils will collapse
- Collagen matrix will ____
- Ineffective ___ ____
- Leads to ____
- Our bonding agents are designed to deal with inherent wetness of dentin, but if its too wet its not as predictable
- With enamel we use hydrophobic resins. Because of the surface E, we are not worried about enamel being wet. It is inherently dry. When we condition enamel, we will dry the tooth after conditioning with acid. Adhesive is hydrophobic and it wets the surface just fine.
- Dentin we can’t use a hydrophobic resin because it is inherently wet. We also can’t dry it like enamel bc then our collegen matrix will collapse. We need to keep it moist as it is inherently so we have that space in the intertubular dentin
- We use hydrophilic adhesive that will penetrate into intertubular dentin
- If its too wet it become unpredictable
- If its too dry it is catastrophic
- Hydrophillic adhesives have something in there to deal with the water so if you were unsure it would better to be too wet than too dry.
Dentin Wetness: Etch & RinseAfter conditioning dentindentin must be wet
prevent collagen collapse
Too little waterCollagen matrix will collapse
Intertubular dentin
Fuzzy Velcro
They are hydrated (like spaghetti in a bowl of water)
Take out water and fibrils will collapse
Ineffective resin penetration
Leads to nanoleakage
Our bonding agents are designed to deal with inherent wetness of dentin, but if its too wet its not as predictable
With enamel we use hydrophobic resins. Because of the surface E, we are not worried about enamel being wet. It is inherently dry. When we condition enamel, we will dry the tooth after conditioning with acid. Adhesive is hydrophobic and it wets the surface just fine.
Dentin we can’t use a hydrophobic resin because it is inherently wet. We also can’t dry it like enamel bc then our collegen matrix will collapse. We need to keep it moist as it is inherently so we have that space in the intertubular dentin
We use hydrophilic adhesive that will penetrate into intertubular dentin
If its too wet it become unpredictable
If its too dry it is catastrophic
Hydrophillic adhesives have something in there to deal with the water so if you were unsure it would better to be too wet than too dry.
Laboratory Study
At this time we didn’t know how wet the dentin needed to be
After putting acid on tooth, clinicians would dry the tooth off and then they would end up with sensitivity because adhesive wouldn’t completely penetrate into the tooth and then they would have ____of ____ in the tooth which would cause water to move into tubules and cause pain
Some adhesives have different solvents in them ____ ___ ____
If you over dry tooth the bond strengths____ dramatically
- Bond of composite to tooth is weaker
- Exception: ____
- Has ____ as solvent and if you over dry it, it would just remoisten itself.
You are not bonded to dry dentin
If it says to dry the dentin, there is probably water as the solvent
Laboratory Study
At this time we didn’t know how wet the dentin needed to be
After putting acid on tooth, clinicians would dry the tooth off and then they would end up with sensitivity because adhesive wouldn’t completely penetrate into the tooth and then they would have microgaps of air in the tooth which would cause water to move into tubules and cause pain
Some adhesives have different solvents in them
Acetone
Alcohol
Water
If you over dry tooth the bond strengths drop dramatically
Bond of composite to tooth is weaker
Exception: SBMP
Has water as solvent and if you over dry it, it would just remoisten itself.
You are not bonded to dry dentin
If it says to dry the dentin, there is probably water as the solvent
- Dentin BondingDevelopment
- ____ generations
- chronologic
- Classification
- ____ generations
- There will be a component that is c_____ with our ___
- There will be a component that is ___: preparing the ___ to deal with ____
- Has primer and hydrophilic adhesive in it
- Third component will be _____
- More compatible with our hydrophobic ___ ____
Dentin BondingDevelopment
seven generations
chronologic
Classification
There will be a component that is conditioning with our acid
There will be a component that is priming: preparing the dentin to deal with water
Has primer and hydrophilic adhesive in it
Third component will be hydrophobic
More compatible with our hydrophobic composite resin
First Generation
- (1950-1970’s)
- ____ ____
- Because of inorganic components of enamel, they would work
- These adhesives would ___ ___ on ___
- Very ___bond strengths
- _____MPa
- First commercial dentinal adhesive
- ____ - SS White (1965)
- claimed chemical bond to ____
- ____ - SS White (1965)
- retention only ___% at 6 months (half of restorations falling out in first 6 months)
- Class 5
- There is no mechanical retention
- It stays in there bc of adhesive and only adhesive
- Retention studies: type of filling done on a certain class of cavity
First Generation
(1950-1970’s)
Hydrophobic monomers
Because of inorganic components of enamel, they would work
These adhesives would NOT work on dentin
Very low bond strengths
2 to 3 MPa
First commercial dentinal adhesiveCervident - SS White (1965)
claimed chemical bond to calcium
retention only 50% at 6 months (half of restorations falling out in first 6 months)Class 5
There is no mechanical retention
It stays in there bc of adhesive and only adhesive
Retention studies: type of filling done on a certain class of cavity
Second Generation
- (late 70’s to mid 80’s)
- Added ___ ___ ___
- Enhanced ___ ____
- claimed chemical bond to___
- smear layer predominately____
- Because there was fear of ___ ____
- We didn’t know if it would damage the pulp/nerve
- These adhesives were trying to penetrate thru layer of ____
- This was one of the initial problems
- Because there was fear of ___ ____
- ___ bond strengths
- ___ MPa
- Not strong
- We should be 15-20 to be predictable adhesion
- Retention ___% at 1 year
- Class 5
- 30% still falling out
Second Generation
(late 70’s to mid 80’s)
Added Phosphorous-ester monomers
Enhanced surface wetting
claimed chemical bond to calcium
smear layer predominately intactBecause there was fear of etching dentin
We didn’t know if it would damage the pulp/nerve
These adhesives were trying to penetrate thru layer of debris
This was one of the initial problems
Low bond strengths5 to 6 MPa
Not strong
We should be 15-20 to be predictable adhesion
Retention 70% at 1 year
Class 5
30% still falling out
Third Generation
- (mid-80’s)
- Mechanism of action
- Introduced mildly ___ ____ ____
- You are not putting __ ___ on the tooth yet. In this stage we are just using ___ ____
- More compatible with water rich ___
- Acidic–> it will penetrate ___ ___
- Hydrophillic–> it will penetrate water rich ___ ___
- _____/____ smear layer
- Introduced mildly ___ ____ ____
- ___ bond strengths
- ____ short / long term success
Third Generation
(mid-80’s)
Mechanism of actionIntroduced mildly acidic hydrophilic monomer
You are not putting separate acid on the tooth yet. In this stage we are just using liquid adhesives
More compatible with water rich dentin
Acidicà it will penetrate smear layer
Hydrophillicà it will penetrate water rich intertubular dentin
Modified/altered smear layer
Moderate bond strengths
Improved short / long term success
Fourth Generation: ___ ___by which we measure all other adhesives
(early 1990’s)
__ and ___: __ step
Apply acid and then we rinse it
Multi-step
1) ___ ____
- Use ___ acid
- ____smear layer
- Acid is a separate step in this generation
Our adhesive is ___bottles
2) ___
* Compatible with _____
3) ___
- Hydrophobic bonding resin
- Very compatible with ____
___ bond strengths
Retention_____ % at _ yrs
Class 5
Examples
__ ___ ___ ___, ___ _ _
If I was bonding to enamel, I could skip step___
Typically bonding to___dentin and enamel
Fourth Generation: GOLD STANDARD by which we measure all other adhesives
(early 1990’s)
Etch and Rinse 3 step
Apply acid and then we rinse it
Multi-step1) Condition dentin
Use phosphoric acid
Remove smear layer
Acid is a separate step in this generation
Our adhesive is two bottles2) Primer
Compatible with water rich dentin
3) Adhesive
Hydrophobic bonding resin
Very compatible with resin
High bond strengths
Retention 98 to 100 % at 3 yrs
Class 5
Examples
Scotchbond Multi-Purpose
Optibond FL
If I was bonding to enamel, I could skip step 2
Typically bonding to both dentin and enamel
Conditioner
- ___ alteration of surface acids
- ____, citric,maleic, nitric
- Removes dentinal __ ___
- exposes ___ ____
- Simultaneous ___ ___
- Rinse
- keep ___
ConditionerChemical alteration of surfaceacids
phosphoric, citric,maleic, nitric
Removes dentinal smear layer
exposes collagen fibrils
Simultaneous enamel etch
Rinse
keep moist
Primer
- ____ monomers
- Dissolved in ___ ___ or ____
- ____water that are in the dentin
- ____ collagen network
- Promotes infiltration into___
- Lightly __ ___
- Drive off solvents, water
- If dealing with enamel you will dry it.
- If dealing with dentin you don’t want to overdry it
- Recommendation: Don’t use an air water syringe. Use high suction to pick up excess water
- Transforms ___ to____
- Once it gets into dentin it has done its job.
- Instructions say to airdry primer. Purpose of this is to ___ the ____
- ____ monomer
- Link bw the ____ and ___
- Example ____
PrimerHydrophilic monomers
Dissolved in acetone, alcohol, or water
Displaces water that are in the dentin
Infiltrate collagen network
Promotes infiltration into collagen
Lightly air dry
Drive off solvents, water
If dealing with enamel you will dry it.
If dealing with dentin you don’t want to overdry it
Recommendation: Don’t use an air water syringe. Use high suction to pick up excess water
Transforms hydrophilic to hydrophobic
Once it gets into dentin it has done its job.
Instructions say to airdry primer. Purpose of this is to evaporate the solvent.
Primer
Bifunctional monomer
Link bw the
hydrophilic collagen
hydrophobic resin (step 3)
Example
HEMA
Adhesive Resin (Hydrophobic)
- ___or ____-filled monomers
- equivalent to ___ bonding
- Bis-GMA, UDMA, TEGDMA
- Stabilize the __ ___
- ___ ___ remaining pores
- Resin ____
- Links primer to composite resin
- Fill up remaining pores in hybrid layer
- Hybrid Layer: ____ layer
- Conditioner _____ dentin
- Interdiffused with ___ ____ monomer
- ____ water
- ___fcnal
- Resin mechanically ____ ____
Adhesive Resin (Hydrophobic)Unfilled or lightly-filled monomers
equivalent to enamel bonding
Bis-GMA, UDMA, TEGDMA
Stabilize the hybrid layer
Fills up remaining pores
Resin tags
Links primer to composite resin
Fill up remaining pores in hybrid layer
Hybrid Layer: Interdiffusion layer
Conditioner demineralizes dentin
Interdiffused with low-viscosity monomer
displaces water
bifunctional
Resin mechanically interlocks collagen
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Mechanical Properties19
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Physical Properties40
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Optical Properties39
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Composition and Properties of Dental Amalgam39
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Resin 125
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Resin II28
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Bonding Agents30
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Noble Metal Alloys22
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Elastomeric Impression Materials27
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Gypsum35
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Glass Ionomers37
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Alginate27
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Dental Cements49
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Pituitary Gland42
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Casting and Soldering Investments58
