Glass Ionomers Flashcards
}Amalgam toxicity
}
Last exam:
Reasons for reduction of use of amalgam –> ___ ___
Only use it when its ___ ___
Last exam:
Reasons for reduction of use of amalgam à mercury toxicity
Only use it when its absolutely necessary
Ideal Direct Restorative Materials
}Biologically ___
}Mechanically___
}Chemically___
}____
}Change phase from ___ to ___ at room temperature/body temperature within a ___ time
}Match the properties of ___ ___
}
}Good___ to ___ ___ (Enamel and Dentin)
}____}
- Today we are doing the last direct restorative materials*
- If material has all those properties*
- What else can make a material better.*
- Less expensive*
- Good adhesion to tooth structure (enamel and dentin)*
- Composite and amalgam have __ ___ to tooth structure.*
- We have to use __ ___*
- It is better if it can adhere itself*
- Anticaires*
- If the material can treat the disease that’s even better*
- The material we talk about today has these two added properties but the other properties are somewhat c____*
}Biologically acceptable
}Mechanically strong
}Chemically inert
}Esthetic
}Change phase from manipulable to solid at room temperature/body temperature within a reasonable time
}
}Match the properties of tooth structure
}
}Good Adhesion to Tooth Structure (Enamel and Dentin)
}Anti-caries
}
Today we are doing the last direct restorative materials
If material has all those properties
What else can make a material better.
Less expensive
Good adhesion to tooth structure (enamel and dentin)
Composite and amalgam have no adhesion to tooth structure.
We have to use bonding agent.
It is better if it can adhere itself
Anticaires
If the material can treat the disease that’s even better
The material we talk about today has these two added properties but the other properties are somewhat compromised
Overview of the Lecture
}Glass Ionomer (GI)
}Resin-modified glass ionomer (RMGI)
}Compomer
}Glass Ionomer (GI)
}Resin-modified glass ionomer (RMGI)
}Compomer
History of the Development of GIs
}1920s
__ ___cements
}___ ___ ___ cements
____ cements.
}1969
}first ___ ___patent by Dr. Wilson
}1970
}first glass ionomer ___ product ASPA (___ ____ ___ ____)
In the 1920s, 3 categories of cement exist in the market
All those are acid base reaction cementà Zn PO4 and Silicate Cement
Zn O reacts with ___ ___ This will be ____ cement
Reactive Glass reacts with ___ __ will be the ___ ___. This was material for___ region at that time.
By 1960 the carboxylate cement was developed
Mix __ ___ with ____ ____–> carboxylate cement
By 1969, Dr. Wilson developed ___ ___r cement. __ ___r mixed with ___ ___
We can see those are in similar category of cement materials
1970: the first ___l products appeared on the market
}1920s
}zinc phosphate cements
}zinc oxide eugenol cements
}silicate cements.
}1969
}first glass ionomer patent by Dr. Wilson
}1970
}first glass ionomer cement product ASPA (Alumino-Silicate-Poly-Acrylate)
In the 1920s, 3 categories of cement exist in the market
All those are acid base reaction cementà Zn PO4 and Silicate Cement
Zn O reacts with phosphoric acid. This will be Phosphate Zn Oxide cement
Reactive Glass reacts with phosphoric acid will be the silicate cement. This was material for anterior region at that time.
By 1960 the carboxylate cement was developed
Mix Zn O with polyacrylic acid-> carboxylate cement
By 1969, Dr. Wilson developed Glass ionomer cement. Glass Powder mixed with Poly Acid
We can see those are in similar category of cement materials
1970: the first commercial products appeared on the market
Traditional Glass Ionomer
}Definition
}A ___r-based material that hardens following an ___ ___ reaction between ____ glass powder and an aqueous solution of ___
}
}Composition
}A ______(FAS) glass powder
}Maximum size: ___ micron
}___-leachable
}An ionic polymer (polymer or copolymer of ___ ___)
}___
}___ ___
- Water based so its Hydrophillic*
- Has a better____ to our tooth structure*
- Composition of this material is this glass poweder*
- Glass powder is made by ___ ___ ____*
- Max size of particleà compare this to composites*
- Another main compositon is ionic polymer*
- This polymers can be a co polymer from a different acid*
- Water: reaction needs water*
- T Acid: another modification of this material to improve ____ properties of material*
Traditional Glass Ionomer
}Definition
}A water-based material that hardens following an acid-base reaction between fluoroaluminosilicate glass powder and an aqueous solution of polyacid.
}
}Composition
}A fluoroaluminosilicate (FAS) glass powder
}Maximum size: 13-19 micron
}Ion-leachable
}An ionic polymer (polymer or copolymer of carboxylic acids)
}Water
}Tartaric acid
Water based so its Hydrophillic
Has a better wetting to our tooth structure
Composition of this material is this glass poweder
Glass powder is made by Fluoride, Aluminum and Silicate
Max size of particleà compare this to composites
Another main compositon is ionic polymer
This polymers can be a co polymer from a different acid
Water: reaction needs water
T Acid: another modification of this material to improve manipulation properties of material
Traditional Glass Ionomer
- Setting Reaction:*
- Acid in water, ___ ion is released*
- Acid will attack the ___ (reactive glass powder) and those ___ will be released*
- It forms a ___ around those glass powders.*
- The glass powders work as a “____”*
- Those ions will react with those ___ __ and form a __ ___ and the material will be hardened.*
- Note: Fluoride is ___ in this matrix.*
Setting Reaction:
Acid in water, H ion is released
Acid will attack the glass (reactive glass powder) and those ions will be released
It forms a gel around those glass powders.
The glass powders work as a “____”
Those ions will react with those fcnal groups and form a crosslink matrix and the material will be hardened.
Note: Fluoride is free in this matrix.
Setting Reaction
}Initial setting – acid-base reaction; only th ____ of each particle is attacked by ___
}releasing __ ___ ___ ions.
}A fully set and mature material is characterized by __ and ______ condensed onto the __ ____r to form a rigid ___ surrounding the partially___ particles.
} ___ ions remain free and are not part of the matrix.
- Initial setting reaction: only surface of particles is attacked by the acid*
- Ions are released*
- The + ions serve as crosslink points to form a rigid matrix and the material will set*
Setting Reaction
}Initial setting – acid-base reaction; only the surface of each particle is attacked by acid;
}releasing Ca, Al and F ions.
}A fully set and mature material is characterized by Ca and Al chains condensed onto the acidic polymer to form a rigid matrix surrounding the partially dissolved particles.
}F ions remain free and are not part of the matrix.
Initial setting reaction: only surface of particles is attacked by the acid
Ions are released
The + ions serve as crosslink points to form a rigid matrix and the material will set
Setting Reaction
}The material needs a period of ___or even months to ___ fully.
}At any time during the reaction and the setting process, they are sensitive to ___ and ___ ____
}Protection is needed ___ the materials set.
- The whole setting reaction takes a long time. Sometimes up to a month*
- During this time, water is very critical*
- Early contamination of material by water, the ___ can leach out and that will influence the reactions*
- During the hardening process, if water is evaporated the surface can____*
- This reaction is sensitive to dehydration or moisture contamination. That’s why protection is needed for this material to set and also after the setting*
Setting Reaction
}The material needs a period of weeks or even months to harden fully.
}At any time during the reaction and the setting process, they are sensitive to dehydration and moisture contamination.
}Protection is needed after the materials set.
The whole setting reaction takes a long time. Sometimes up to a month
During this time, water is very critical
Early contamination of material by water, the acid can leach out and that will influence the reactions
During the hardening process, if water is evaporated the surface can crack
This reaction is sensitive to dehydration or moisture contamination. That’s why protection is needed for this material to set and also after the setting
Fluorine Release
}Fluorine does not exist in the ___ ___ of the glass; fluorine in the glass ___ probably diffuses throughout the ___ and is then released ____
}The physical properties of glass ionomer do not ____ even after fluorine release.
}The ability of GI to r_____ e fluorine is a feature of the fluorine ____ within the matrix.
}Maintain ___ levels of fluorine in the oral environment
- Fluoride is in the matrix*
- Doesn’t exist as a core structure in the material*
- So its free to come in and out*
- When you put it in, the Fluoride can release from the material*
- If you use topical fluoride, the material can ___ the topical Fluoride*
- Its like a Fluoride ___*
- When you place it the fluoride will start to ___*
- And when you add topical fluoride (like from brushing your teeth with fluoride toothpaste) the material will absorb some fluoride*
- And then it will release the fluoride out ____ à Anti-decay properties*
- Fluoride is not skeletal structure.*
- Releasing Fluoride has no detrimental effects on the material*
Fluorine Release
}Fluorine does not exist in the skeletal structure of the glass; fluorine in the glass core probably diffuses throughout the matrix and is then released slowly.
}The physical properties of glass ionomer do not deteriorate even after fluorine release.
}The ability of GI to recharge fluorine is a feature of the fluorine movement within the matrix.
}Maintain constant levels of fluorine in the oral environment
Fluoride is in the matrix
Doesn’t exist as a core structure in the material
So its free to come in and out
When you put it in, the Fluoride can release from the material
If you use topical fluoride, the material can absorb the topical Fluoride
Its like a Fluoride Reservoir
When you place it the fluoride will start to release
And when you add topical fluoride (like from brushing your teeth with fluoride toothpaste) the material will absorb some fluoride
And then it will release the fluoride out gradually. à Anti-decay properties
Fluoride is not skeletal structure.
Releasing Fluoride has no detrimental effects on the material
Chemical Bond to Tooth Structure
}An ___ bond between ___ groups from the ___ ___ and the ___ ___ present on __and ___ is formed.
}An ___ ___ layer forms between tooth structure and GI at the __ ___ interface.
}
- Ca is one of the ion used to connect the ___ ___ the matrix of the ___ ___*
- We have a lot of Ca on tooth surface too*
- When the material sets, the Ca from the __ ___s can react with the ___*
- Our tooth structure can also react with the liquid. The Ca from tooth tooth reacts with the COO fcnal group and form a chemical bond*
- Form a chemical bond to the tooth structure*
Ca is one of the ion used to connect the fcnal groups the matrix of the poly acid
We have a lot of Ca on tooth surface too
When the material sets, the Ca from the glass powders can react with the liq
Our tooth structure can also react with the liquid. The Ca from tooth tooth reacts with the COO fcnal group and form a chemical bond
Form a chemical bond to the tooth structure
Traditional Glass Ionomer
This is a SEM of the material. You can see the ___ particles still in the ___
When you prepare sample some particles come off, leaving a ___ in the surface
This is a SEM of the material. You can see the unreacted particles still in the matrix
When you prepare sample some particles come off, leaving a hole in the surface
Tooth Surface Conditioning
}10-20% ____ acid etch for 10 to 15 sec.
}Many of the dentin tubules remain ___, but the surface is relatively ___
}___ acid – remove ___ ___ ; clean bonding surface; expose ___ for chemical bonding
}
}
When we use this material, like when we use composites, We etch the surface
This material comes with surface conditioning too but Different than the acid we use in composites
This is 10-20% polyacrylic acid
We etch the tooth surface.
Purpose of etching: not to expose __ ___, it is to clean tooth surface and have more Ca exposed so the Ca will be available for the bonding. Removes the smear layer
Tooth Surface Conditioning
}10-20% polyacrylic acid etch for 10 to 15 sec.
}Many of the dentin tubules remain occluded, but the surface is relatively clean.
}Weak acid – remove smear layer; clean bonding surface; expose Ca++ for chemical bonding
}
}
When we use this material, like when we use composites, We etch the surface
This material comes with surface conditioning too but Different than the acid we use in composites
This is 10-20% polyacrylic acid
We etch the tooth surface.
Purpose of etching: not to expose dentin tubules, it is to clean tooth surface and have more Ca exposed so the Ca will be available for the bonding. Removes the smear layer
Tooth Surface Conditioning
}37% _____acid etch dentin for 15 sec and shows the demineralization of the___n rendering it ____ for ion-exchange adhesion.
}37% phosphate acid is contraindicated – ____ tooth surface
}
This is the tooth surface we have after we use orthophosphoric acid to etch tooth surface
This is ready for dental __ ___t but this is too much for glass ionomers.
The purpose of this to remove some of the minerals in the tooth structure. This removes the Ca!
Tooth Surface Conditioning
}37% orthophosphoric acid etch dentin for 15 sec and shows the demineralization of the collagen rendering it unsuitable for ion-exchange adhesion.
}37% phosphate acid is contraindicated – demineralize tooth surface
}
This is the tooth surface we have after we use orthophosphoric acid to etch tooth surface
This is ready for dental bonding agent but this is too much for glass ionomers.
The purpose of this to remove some of the minerals in the tooth structure. This removes the Ca!
Delivery Systems
___ / ____system
___ powder/___ ____ solution
}Limited __ __
}__ ____+_____ ___ ____d/___ (and____ acid), in which the freeze-dried polyacid ___ on ____.
Traditional Glass Ionomer: 2 bottle sys. 1 powder. 1 liq
1st generation: This is the glass powder in there. And this is the Polyacid Soln.
This is not very stable (PA soln)
Limited shelf time
Started to used freeze-dried polyacid powder. They put all the powder in one bottle and the liquid is just water or sometimes it has a tartaric acid. Mix the two and the material wil set
Delivery Systems
}Powder/liquid system
}Glass powder/aqueous polyacid solution
}Limited shelf life
}Glass powder + freeze-dried polyacid/water (and tartaric acid), in which the freeze-dried polyacid dissolves on mixing.
Traditional Glass Ionomer: 2 bottle sys. 1 powder. 1 liq
1st generation: This is the glass powder in there. And this is the Polyacid Soln.
This is not very stable (PA soln)
Limited shelf time
Started to used freeze-dried polyacid powder. They put all the powder in one bottle and the liquid is just water or sometimes it has a tartaric acid. Mix the two and the material wil set
Delivery Systems
}Capsule system=
Like Amalgam Capsules
2 parts in capsule
Activate it using thing on right
Two parts will mix together
And then you put it on the Trutrurator and mix the material
2 other bottles come with the whole set
____
___/___
After you put the GI, After it is set you put glaze to prevent ___ ___ ___of material
Delivery Systems
}Capsule system
Like Amalgam Capsules
2 parts in capsule
Activate it using thing on right
Two parts will mix together
And then you put it on the Trutrurator and mix the material
2 other bottles come with the whole set
Conditioner
Coating/Glaze
After you put the GI, After it is set you put glaze to prevent water contamination/dehydration of material
Difference Between Composite and GI
}Composites
}Hydro___
___ and ____ matrix bind by way of a___ ___ ____
}
}GI
}Hydro___
}The __ ___of the__ ___ reacts with ___, whereas the glass ____remains intact. The glass core exists as ___ in the matrix
Composites: resin based so its hydrophobic. That’s why we use bonding agent also
Filler and resin bind bc we use ____ fillers
GI
The surface layer of the glass powder reacts with acid directly.
The glass core is intact
We don’t need silane coupling agent to bond the powder and the acid. They react together so that’s a ___ ___ in there
GI also has a Surface reaction where core remains intact. (this is like ____–> Hg and Metal alloy have similar rxn to this)
Difference Between Composite and GI
}Composites
}Hydrophobic
}Filler and resin matrix bind by way of a silane-coupling agent
}
}GI
}Hydrophilic
}The surface layer of the glass powder reacts with acid, whereas the glass core remains intact. The glass core exists as filler in the matrix
Composites: resin based so its hydrophobic. That’s why we use bonding agent also
Filler and resin bind bc we use inorganic fillers
GI
The surface layer of the glass powder reacts with acid directly.
The glass core is intact
We don’t need silane coupling agent to bond the powder and the acid. They react together so that’s a chemical bond in there
GI also has a Surface reaction where core remains intact. (this is like Amalgamà Hg and Metal alloy have similar rxn to this)
Difference Between Composite and GI
}Composites –> BISGMA
}GI
Another difference bw Composite and GI is the ____
Matrix is different
This is one of the ___ we use for composites
For GI we use ____. We use __ __ ___ And those are the ___ molecules to form __ __
Whats the difference?
GI liquid is polyacid. What does that mean? It is ____ already. So it doesn’t have ____ ____ for this material.
Put those 3 groups together and form —COOH and this is in a ___. IT doesn’t go thru the polymerization process
GI is ____ chain…don’t have fcnal groups so that makes this ____r than Composites.
It also doesn’t have ___ ring so polymer is easier to ___
Difference Between Composite and GI
}Composites –> BISGMA
}
}
}
}GI
Another difference bw Composite and GI is the matrix
Matrix is different
This is one of the monomers we use for composites
For GI we use copolymers. We use co poly acid. And those are the small molecules to form poly acid
Whats the difference?
GI liquid is polyacid. What does that mean? It is polymer already. So it doesn’t have polymerization shrinkage for this material.
Put those 3 groups together and form —COOH and this is in a liquid. IT doesn’t go thru the polymerization process
GI is linear chain…don’t have fcnal groups so that makes this weaker than Composites.
It also doesn’t have phenyl ring so polymer is easier to move
Traditional Glass Ionomer
}Advantages
}Inherent (chemical) __ to tooth structure.
___ release
}high caries-risk patients
____- it does not ___ other oral structures
}The unset cement mixture exhibits an ___ which can adversely affect exposed ___
}The fully set cement has no ____ effect.
}Less ____ change upon setting
}Coefficient of thermal expansion is similar to ___
}Can be __ ___
We don’t have to use ___ __and it doesn’t___so it can be bulk filled. Saves you ___ in the clinic
Traditional Glass Ionomer
}Advantages
}Inherent (chemical) adhesion to tooth structure.
}Fluoride release
}high caries-risk patients
}Biocompatible - it does not irritate other oral structures
}The unset cement mixture exhibits an acidity which can adversely affect exposed pulp.
}The fully set cement has no acidic effect.
}Less dimensional change upon setting
}Coefficient of thermal expansion is similar to dentin
}Can be bulk filled
We don’t have to use curing light and it doesn’t shrink so it can be bulk filled. Saves you time in the clinic
Traditional Glass Ionomer
}Disadvantages
___ set time
___ sensitivity
}Susceptibility to early ____ contamination
}Prone to____ after setting
}Coating required to provide ____ from____ until final setting occurs
___ polish
____/___mechanical strength
___
}Lack of ____
}Low ___ ___
Surface is rough bc the particle size is much ___ than composites
Material is fairly ____
Not often used for ___ restorations
Traditional Glass Ionomer
}Disadvantages
}Long set time
}Technique sensitivity
}Susceptibility to early moisture contamination
}Prone to desiccation after setting
}Coating required to provide protection from solubility until final setting occurs
}Delayed polish
}Brittleness/low mechanical strength
}Rough
}Lack of translucency
}Low wear resistance
Surface is rough bc the particle size is much bigger than composites
Material is fairly opaque
Not often used for permanent restorations
Resin-Modified Glass Ionomer
}Composition
}a modified polyacrylic acid with ___ ___ ___, ____ (2-hydroxyethylmethacrylate), w___r and ___
}a _____e, fluoroaluminosilicate glass powder
Improved material by adding resins in the monomers
They added a methylacrylic group pendent to the surface of the polyacid
Once you add the methylacrylate group, you also add the photoinitiators in the system
Resin-Modified Glass Ionomer
}Composition
}a modified polyacrylic acid with pendant methacrylate groups, HEMA (2-hydroxyethylmethacrylate), water and photoinitiator
}a radiopaque, fluoroaluminosilicate glass powder
Improved material by adding resins in the monomers
They added a methylacrylic group pendent to the surface of the polyacid
Once you add the methylacrylate group, you also add the photoinitiators in the system
Resin-Modified Glass Ionomer
They have a pendant with the __ ___ in there
__ ___ reaction is still there
But last ___ ___ will react too when you shine the ___ on it. too Once this reacts the material will set
Resin-Modified Glass Ionomer
They have a pendant with the double bond in there
Acid Base reaction is still there
But last double bond will react too when you shine the light on it. too Once this reacts the material
Setting Reaction – Dual or Tri-cure
}__ __ reaction
}____ curing
}______CQ) is the most commonly used __ ____
}___curing
}___ -based __ ___
This is a dual or tri cure reaction.
It also has the acid base reaction
Mode of light curing is ___ as dental composites
Chemical curing: sometimes this material also has the chemical curing systems in there bc if you ___ ___
Also the Material is very___ . Light can’t penetrate too ___ inside the material.
So the pendent needs to cure completely thru the material so they have this chemical curing rxn in there
Resin modified GI has those diff setting reactions
Setting Reaction – Dual or Tri-cure
}Acid-base reaction
}Light curing
}Camphoroquinone (CQ) is the most commonly used photo initiator.
}Chemical curing
}Water-based redox catalysts
This is a dual or tri cure reaction.
It also has the acid base reaction
Mode of light curing is same as dental composites
Chemical curing: sometimes this material also has the chemical curing systems in there bc if you bulk cure.
Also the Material is very opaque. Light can’t penetrate too deep inside the material.
So the pendent needs to cure completely thru the material so they have this chemical curing rxn in there
Resin modified GI has those diff setting reactions
RMGI – Setting Reaction
}The resins are ___-activated to penetration depth of the curing light, providing ___ for the ongoing __ ___ reaction from immediate water___/ ___
}Chemical initiators allow polymerization of___ chains that were not activated via ___.
}The acid-base component has matured to the same degree as that of ____ GIs.
The resin is light activated.
If you want to use this material, you need to pay attention to the light penetration depths.
Some materials have chemical rxn initiators in there and some don’t
Some have dual cure only
If its only dual cure you need to pay attention to the curing depths
Once material is cured by the light, it will help you with ___ ___ and ____.
Not that sensitive to moisture contamination/dehydration anymore.
This will make the material set ___ ___
Acid base reaction is still there like traditional GI.
It still completely reacts until it is finished
Student Question:
If this doesn’t have chem initiator in there, you cant builk full
Only tri cure you can bulk fill. Dual cure you can’t bc the light can’t penetrate beyond some thickness.
RMGI – Setting Reaction
}The resins are light-activated to penetration depth of the curing light, providing protection for the ongoing acid-base reaction from immediate water uptake/loss.
}Chemical initiators allow polymerization of resin chains that were not activated via LC.
}The acid-base component has matured to the same degree as that of conventional GIs.
The resin is light activated.
If you want to use this material, you need to pay attention to the light penetration depths.
Some materials have chemical rxn initiators in there and some don’t
Some have dual cure only
If its only dual cure you need to pay attention to the curing depths
Once material is cured by the light, it will help you with water uptake and loss.
Not that sensitive to moisture contamination/dehydration anymore.
This will make the material set on demand
Acid base reaction is still there like traditional GI.
It still completely reacts until it is finished
Student Question:
If this doesn’t have chem initiator in there, you cant builk full
Only tri cure you can bulk fill. Dual cure you can’t bc the light can’t penetrate beyond some thickness.
Advantages
}Inherent (chemical) ___ to tooth structure.
___ release
____e it does not irritate other oral structures
____ setting time (on demand)
}Better ___ and ___ properties
___ __ ___ as ___( fluoride release)
If patient is high decay risk, then you want to maximize fluoride release and should use traditional GI
Setting time is on demand now
A little more ____ now
Advantages
}Inherent (chemical) adhesion to tooth structure.
}Fluoride release
}Biocompatible it does not irritate other oral structures
}Shorten setting time (on demand)
}Better mechanical and esthetic properties
Not as much as traditional (fluoride release)
If patient is high decay risk, then you want to maximize fluoride release and should use traditional GI
Setting time is on demand now
A little more translucent now
