GIC restorations Flashcards
What are the key attributes of glass ionomers?
see slides
What are the types of GIC restorations?
True GIC - auto-cure (eg. equia forte)
Resin-modified GIC which is light cured
What are the types of true glass ionomers?
Stronger restorative materials
Weaker temporary or surface protection materials (eg GC FUJI 7)
What are the types of resin-modified glass ionomers?
see slides
How does GIC work?
Acid base reaction results in enamel and dentine “melting” into the restoration. This creates a bond because both ions from the composite and the ions of the enamel are mixed and hardened.
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Chemical fusion to enamel and dentin
An ongoing water-based ion-leakage over time
Prevents microleakage
Some important GIC clinical tips to remember:
Don’t over-dry the cut dentine (GIC is water based) Use a cotton pledget or very light air drying to dry the cavity
Don’t allow any saliva to contaminate dentine surface
After GIC set cover with an unfilled resin (not a dentine binding agent) and light cure
What are the indications for using GIC?
Fissure seals in young patients
Small occlusal permanent restorations
Class 5 restorations outside the aesthetic zone and some class 3s
Temporary caries control restorations
Temporary restorations after cusp fractures
As luting cements
GIC has inadequate strength for class 2 permanent fillings
Never use for a class 1 under load
What are the indications for using GIC?
Proximal white spot lesions
Fissure seals in young patients
Small occlusal permanent restorations
Class 5 restorations outside the aesthetic zone and some class 3s
Temporary caries control restorations
Temporary restorations after cusp fractures
As luting cements
GIC has inadequate strength for class 2 permanent fillings
Never use for a class 1 under load (fine for small occlusal only)
How is a glass ionomer fissure seal administered?
Clean out fissure with probe
Fissure conditioning with 10% polyacrylic acid
Wash and air-dry fissure gently
Syringe in viscous true GIC, rub over fissure with a gloved finger covered with unfilled resin/light cure
How is … treated?
Composite bonding can’t bond to demineralized enamel - Only GIC can
Remineralize with good plaque hygiene and fluoride application
How is lost tooth structure replaced?
Replace lost tooth structure with GIC only roughen dentine with a slow bur, condition with polyacrylic acid/rinse/inject GC equia forte.
How is equia forte treated?
Water spray is necessary after it has hardened and needs trimming.
Normal chemical set true GIC
After set needs moisture protection
Why does FUJI VII release the most fluoride?
Weak material with high liquid to powder ratio
problems with GIC:
Another problem with GIC’s is that they dissolve in highly oral acidic environments
GIC acts as a sacrificial anode
What is the main limitation of composite and how is GIC better for this purpose?
Composite can fail and GIC is less likely to fail due to bonding microleakage.
How strong is the bond between composite and dentine?
Resin dentine bonds degrade over time due to presence of Matrix Metalloproteinases
How can most reliable bonding be created with composite material?
Bonding the composite to enamel rather than dentine
What are the limitations of (composite)?
Reduces composite volume - polymerization shrinkage
Reduces microleakage risk near the pulp in deep composite restorations
and 2 more points
What is the best indication for sandwich restorations?
Best indication for a sanwich restoration is deep class 1 caries
What are the benefits of using …?
Poor abrasion resistance
Low compressive strength
Low fracture resistance
Susceptible to dehydration
The physical and aesthetic properties are inferior
What is GIC used for in sandwich technique?
A thick layer of GIC acts as a dentine substitute to ensure no microleakage near the pulp
How much GIC should be used in sandwich technique?
> 2mm or it will fail.
What are the types of sandwich restorations?
Open and closed sandwich
If we have a lot of tooth missing you want glass ionomer near the pulp
What are the problems with open sandwich technique restorations?
GIC dissolution
Difficult to bond a true GIC to a composite resin
What should be considered before GIC use?
In high caries risk GIC is better than amalgam/composite
Never put open sandwich glass at contact point.
How is composite bound to GIC?
It is difficult to bond composite to equia forte. This is done with scotch bond or RIVA bond LC. Scotch bond is better due to use of it already for normal composite restorations.
Should GIC be etched?
Don’t etch the GIC only etch the enamel
How should GIC be used?
Before curing shape marginal ridge and contours
Carve from midpoint of marginal ridge in both directions
Why use a GIC sandwich restoration?
Laminating composite over GIC removes the wear and strength problems of an occlusal GIC restoration
Reduces volume of posterior composite = less resin polymerization shrinkage and stress
GIC creates a true chemical-ionic bond to tooth structure with a long-term seal to dentine/tooth
GIC is a biomimetic and remineralized soft affected caries
GIC has similar coefficient of thermal expansion to dentine
Long-term fluoride release and re-charge
Indicated for deep posterior Class I and
Class II - Class II floor of box, with no enamel margin
