Gic new / endodontics courses

www.indiandentalacademy.comwww.indiandentalacademy.com
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education

DEFINITIONS:
“Glass-ionomer is the generic name of a group of materials
that use silicate glass powder and aqueous solution of
polyacrylic acid”
-Kenneth J Anusavice
“Glass ionomer cement is a basic glass and an acidic polymer
which sets by an acid- base reaction between these components”
JW McLean, LW Nicholson. AD Wilson (1994)

CLASSIFICATIONS:
According to skinners
Type I – Luting
Type II- Restorative
Type III- Liner and base
According To Mc Lean, Nicholson and Wilson
(1994):
1. Glass ionomer cement
a. Glass polyalkeonates
b. Glass polyphosphonates
2. Resin modified GIC
3. Polyacid modified GICwww.indiandentalacademy.comwww.indiandentalacademy.com

According to GJ Mount:
1. Glass ionomer cements
a. (i) Glass polyalkeonates
(ii) Glass polyphonates
b. Resin modified GIC
c. Polyacid modified composite resin
2. a. Auto-cure
b. Dual cure
c. Tri cure
3. a. Type I – Luting
b. Type II - Restorative
Type II. 1. Restorative aesthetic
Type II. 2. Restorative reinforced
c. Type III- Lining or Base

According to Sturdevent:
1. Traditional or conventional
2. Metal modified GIC
a. Cermets
b. Miracle mix
3. Light cured GIC
4. Hybrid (Resin modified GIC)
5. Polyacid modified resin composite or Compomer

VII. According to intended applications:
1. Type I - Luting
2. Type II - Restorative
3. Type III - Fast setting lining
4. Type IV - Fissure sealants
5. Type V - Orthodontic cements

6. Type VI - Core build up material
7. Type VII - High fluoride releasing command set GIC
8. Type VIII - GIC for Atraumatic Restorative Treatment
(ART)
9. Type IX - Geriatric and Paediatric GIC

COMPOSITION:
POWDER:
The composition of the glass is an acid soluble
calcium aluminosilicate glass.
Formed by fusing silica[Sio2], alumina [Al2O3],
calcium fluoride / fluorite(CaF2), metal oxides
and metal phosphates at 11000
C to 15000
C
temperature.
The glass is crushed, milled and then ground to a
fine powder {20u – 50uwww.indiandentalacademy.comwww.indiandentalacademy.com

COMPONENTCOMPONENT WEIGHT%WEIGHT%
SiOSiO22 [quartz][quartz] 2929
AlAl22OO33 [alumina[alumina]] 16.616.6
CaFCaF22[fluorite][fluorite] 34.234.2
NaNa33AlFAlF66[cryolite][cryolite] 55
AlFAlF33 5.35.3
AlPOAlPO44 9.99.9
COMPOSITION OF CALCIUM FLUROALUMINOSILICATE
GLASS POWDER

LIQUID:
The liquid was an aqueous solution of
polyacrylic acid in a concentration of about 50%.
The liquid was quite viscous and tended to gel
over time.
Hence, acrylic acid was copolymerised with other
acids such as iticonic ,maleic,and tricarboxylic
acid.

The use of copolymers are:
- Decrease the viscosity of the liquid
- Reduces the tendency for gelation
and thus improving storage
- Increases the reactivity of the liquid

WATER:
It is one of the most important constituents
of glass ionomer cement.
It is the reaction medium
ADDITIVES:
 Tartaric acid:
The principle obstacle to developing a
practical glass ionomer was the sluggish
nature of the set with minimal working
time and slow hardening.www.indiandentalacademy.comwww.indiandentalacademy.com

ANHYDROUS CEMENT:
The polyacrylic acid can be
vacuum dried and incorporated with
the glass powder.
The liquid then used can be
either water or a dilute aqueous
solution of tartaric acid.

SETTING REACTION:
When the powder and liquid are mixed to
form a paste,
The surface of the glass ionomer particles
is attacked by the acid. Calcium,
aluminium, sodium and fluoride ions are
leached into the aqueous medium.
Polyacrylic acid chains are cross-linked by
calcium ions
and form a solid form.www.indiandentalacademy.comwww.indiandentalacademy.com

Within the next 24 hours a new phase
forms in which Al ions become
bound within the cement mix leading
to a rigid cement.

Some of the sodium ions may replace the
hydrogen ions of carboxylic groups,
where as the rest combine with fluorine
ions forming sodium fluoride which
uniformly disperse within the set cement.
During the maturating process the cross-
linked phase is also hydrated by the same
water used as the medium.

SETTING REACTION OF GIC
The calcium polyacrylate chains form first, followed by the aluminium
polyacrylate chains.
Note that fluoride ions are released from the glass, but lie free within the
matrix and are therefore able to move out of the set cement and return
back to the matrix.

THE ROLE OF WATER:
The glass ionomer cements are water-based cements.
It’s functions include:
 It is reaction medium.
 It serves to hydrate the siliceous hydrogel and the
metal salts formed.
 It is essential part of the cement structure. If water
is lost from the cement by desiccation while it is
setting, the cement-forming reactions will stop.www.indiandentalacademy.comwww.indiandentalacademy.com

Water present in the set cement can be arbitarily classified
into:
 “loosely bound water” which is readily removed by
desiccation. This water is loosely bound to the calcium
ions
 “tightly bound water” which cannot be removed.
Tightly bound water is associated with the hydration
shell of the aluminium cation- polyacrylate bond and
some silica gel water.www.indiandentalacademy.comwww.indiandentalacademy.com

ADHESION:
Glass ionomer cements have the important
property of adhering to untreated enamel and
dentin. It reacts with the smear layer on cut
dentin and also bonds to other reactive polar
substrates such as the
base metals.
Adhesion – 225MN/m2 after 7 days

ADHESION OF GIC
Polyalkenoic acid attacks the dentine and enamel and displaces phosphate and
calcium (or strontium) ions.
These migrate into the cement and develop an ion enriched layer firmly attached
to the tooth structure.
Dentinal tubules will remain sealed and microleakage can only occur into the
cement. www.indiandentalacademy.comwww.indiandentalacademy.com

SURFACE CONDITIONING:
It is the pre-treatment of
the surface to eliminate the wide variation
found in the structure of tooth surfaces
following cutting.

Different types of surface conditioners used are:
Polyacrylic acid:
 10% polyacrylic acid for 10 seconds.
 It removes surface debris and smoothes out
irregularities.
 It tends to open up dentinal tubules.
 It is the conditioner of choice as it is a part of the
cement forming system.

Citric acid:
50% citric acid for 5 seconds was the
earliest conditioner used
Tannic acid:
25% for 30 seconds.
Ferric chloride:
2% solution provides metal linkage between
collagen and GIC without opening up
dentinal tubules.

BIOCOMPATIBILITY:
The glass ionomer cements are therapeutic
materials. Their adhesion to tooth material
ensures that they provide an excellent and
enduring marginal seal, thus eliminating
secondary caries while sustained release of
fluoride confers resistance to caries on
adjacent tooth material (I.e there is a
reduction in ‘contact’ caries).

FLUORIDE RELEASE:
Glass ionomer has a cariostatic effect.
PULP RESPONSE:
The overall pulpal biocompatibility
of these materials has been
attributed to the weak nature of the
polyacrylic acid which is unable to
diffuse through dentin due to its high
molecular weight.www.indiandentalacademy.comwww.indiandentalacademy.com

ASTHETICS:
The glass ionomer cement is an aesthetic
filling material because it has a degree of
translucency which arises because it’s filler is
a glass.
The colour of glass ionomer remains
unaffected by oral fluids as compared to
composites which tend to stain.
Translucency increases as they age and is
reflected by a decrease in opacity.

DIMENSIONAL STABILITY:
A correctly manipulated and
protected glass ionomer material
shows a volumetric setting
contraction of approximately 3%
which develops slowly through the
setting process.

MECHANICAL PROPERTIES:
COMPRESSIVE STRENGTH- 150MPa
TENSILE STRENGTH-6.6MPa
HARDNESS-48 KHN
SOLUBILITY AND DISINTEGRATION-
The initial solubility is high, due to leaching of
intermediate products.
ESTHETICS – inferior to silicate and composites.www.indiandentalacademy.comwww.indiandentalacademy.com

CLINICAL CONSIDERATIONS:www.indiandentalacademy.comwww.indiandentalacademy.com

The clinical development and use of glass
ionomer cements was first described by Mc
Lean and Wilson (1977). Initial use of GIC
as preventive restorations has now
expanded to cover many other roles

INDICATIONS:
1. RESTORATIVE MATERIALS:
• Restoring of erosion/ abrasion
lesions without cavity preparation.
• Sealing and filling of occlusal pits
and fissures
• Restoration of deciduous teeth.
• Restoration of class III lesions,
preferably using a lingual
approach with labial plate intact.www.indiandentalacademy.comwww.indiandentalacademy.com

• Repair of defective margins in
restorations
• ‘Minimal cavity preparations’ –
proximal lesions –buccal and
occlusal approach (tunnel
preparation)
• Core build-up
• Provisional restorations where future
veneer crowns are contemplated
• Sealing of root surfaces for over
dentures.

2. FAST SETTING LINING CEMENT AND
BASES:
• Lining of all types of cavities where a
biologic seal and cariostatic action are
required
• Replacement of carious dentin or the
attachment of composite resins using the
acid etch technique
• Sealing and filling of occlusal fissures
showing early signs of caries.

3. LUTING CEMENT:
Fine grain versions of the glass ionomer
cement are used.

CONTRAINDICATIONS:
 Class IV carious lesions of fractured
incisors.
 Lesions involving large areas of labial
enamel where esthetics is of major
importance
 Class II carious lesions where
conventional cavities are prepared;
replacement of existing amalgam
restorations.
 Lost cusp areas.www.indiandentalacademy.comwww.indiandentalacademy.com

CLINICAL PROCEDURES FOR
PLACEMENT:
To ensure the successful use of glass ionomers
3 parameters that
must be controlled are:
- Conditioning of the tooth surface
- Proper manipulation
- Protection of the cement during setting

1. Select the appropriate shade of the cement.
2. Isolate the tooth with rubber dam where there
is any risk of gingival Seepage or bleeding.
3. Prepare the cavity ---Erosion/abrasion lesion:-
clean only with pumice slurry---Carious lesion:
conventional instrumentation to remove caries
and provide some mechanical retention.

4. Where there is less than 0.5mm of
remaining dentin. Line the cavity with a setting
calcium hydroxide.
5. Apply a Surface conditioner to the cavity to
remove the smear layer and improve
adhesion.
6. Wash thoroughly for 30seconds with

7. Dispense the cement on a cooled
glass slab and mix quickly (30 seconds
for hand mixing and 10 seconds for
machine mixing). Alternatively a paper
pad can be used. The mix should have a
glossy appearance.
8. The surface should be dried but
not desiccated as this tends to reduce
the wettability.
9. Insert the cement using a spatula
or a syringe

10. Place a preshaped matrix wherever
possible.
Allow to set.
11. Remove the matrix and immediately
apply varnish or bonding agent.

13. Trim any excess external to the
cavity with scalpel blade.
14. Reapply varnish or bonding agent.
15. The final polishing should be delayed
till the next appointment or at
least 24hours.
16. Reapply varnish or bonding agent
after polishing.www.indiandentalacademy.comwww.indiandentalacademy.com

DISPENSING AND MIXING:
Glass ionomers are available
commercially in two forms:
- Powder and liquid supplied
separately, or hand mixing.
- Encapsulated, or mechanical
mixing.

HAND MIXING:
Certain points to noted while mixing and
dispensing GIC are:
 Low exotherm while mixing GIC
enables all the powder to be
incorporated into the liquid at the same
time though not in a hurry as through
mixing is required.
 The recommended P:L ratio should
be followed.(3:1)www.indiandentalacademy.comwww.indiandentalacademy.com

 Mixing on a chilled slab can
significantly prolong working and setting
time.
 Plastic or agate spatula are usually
used for mixing

 A smooth glossy plastic
paste should be produced by
spreading the mix across the slab
and then re-gathering it to
reduce entrapped porosity

 A dry mix will not adhere to the tooth
due to insufficient wetting. A glossy mix
indicates the presence of free surface
polyacid for ion displacement at the
enamel dentin interface.
 Setting time – Type I – 4 to 5
minutes
Type II- 7 minuteswww.indiandentalacademy.comwww.indiandentalacademy.com

MANIPULATION OF GIC
a. Dispense both powder and liquid
carefully. Turn the liquid bottle to the
horizontal briefly to allow liquid to flow
into the tip before turning it to the
vertical and squeezing out a single
drop.
b. Divide the powder into two equal parts
and prepare to mix.
c. Incorporate the first half of the powder
within 10 seconds, rolling the powder
into the liquid without spreading the
mix over the slab. Do not spatulate too
much.
d. Complete the mixing within 25-30
seconds. For preference, place into a
disposable syringe for transfer to the
cavity.

USES
 BAND AND BRACKET
CEMENTATION.
 CORE BUILD-UP CEMENTS – TYPE VI
GIC.
 HIGH FLUORIDE RELEASING
COMMAND SET GIC-TYPE VIII GIC.
 GIC FOR ATRAUMATIC
RESTORATIVE TREATMENT TYPE VIII
GIC.

 GERIATRIC AND PAEDIATRIC GLASS
IONOMER CEMENTS- TYPE IX GIC
 GLASS IONOMER CEMENTS IN
ENDODONTICS
 ROOT CANAL SEALING
 RETROGRADE ROOT CANAL FILLING
 PERFORATION REPAIR
 TREATMENT OF VERTICAL FRACTURES
 CORONAL SEALING AFTER ROOT CANAL
TREATMENT

Uses of GIC
EROSION / ABRASION LESIONS
CLASS III
CARIES
MNIMAL CAVITY PREPARATIONS
CLASS V CARIOUS LESIONS

Pits and fissures Primary Teeth restorations
Bracket Bonding

Luting of crowns
Core Build-up

GLASS IONOMER AS LINER AND BASE
Glass-ionomer cement as a lining. A lining is
used to protect the pulp from temperature
change so the lining needs to be only 0.5mm
thick overall.
Glass-ionomer cement as a base. The entire
cavity should be filled with glass-ionomer
cement; then cut back to expose sound enamel
margins.

Thank YouThank Youwww.indiandentalacademy.comwww.indiandentalacademy.com

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