GLASS IONOMER CEMENT
Dept. of conservative dentistry &
JAIPUR DENTAL COLLEGE
7.MIXING OF CEMENT.
8. WORKING TIME AND SETTING TIME.
10.PROPERTIES OF GLASS IONOMER CEMENT.
16. MODIFICATIONS OF GIC.
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.
•1965 –A.D Wilson mixed dental silicate glass powder & aqueous
solutions of various organic acids including poly acrylic acid
Set cement is sluggish
Not reported or published.
• The invention of glass ionomer cement was done in 1969.first
reported by Wilson and Kent in 1971.( ASPA I)
• First practical material: ASPA II in1972 by Crisp and Wilson,added
• ASPA III- Methyl alcohol was added.
• First marketable material, ASPA IV in 1973
• Luting agent ASPA IVa in 1975 by Crisp and Abel
•Metal reinforced cements in 1977 by Sced and Wilson
• Cermet ionomer cements in 1978 by Mc Lean and Glasser
• Improved traslucency, ASPA X by Crisp, Abel,Wilson in 1979
• Water activated cements, ASPA V in 1982 by Prosser et al.
• Glass ionomer-term coined by wilson & kent
glass-alumino silicate glass particles
ionomer-poly carboxylic acid.
• ISO terminology- poly alkenoate cement.
• Since its co-efficient of thermal expansion similar to dentin and
its extensive usage to replace the dentin ,has given different names
Man made dentin
•Introduced into u.s as ASPA-Alumino silicate polyacrylate
• The glass ionomer powder is an acid soluble calcium fluoroaluminosiicate glass-
ion leachable glass.
• Composition of two commercial glasss ionomers
Compound Composition A(wt%) Composition B(wt%)
SiO2 41.9 35.2
Al2O3 28.6 20.1
AlF3 1.6 2.4
CaF2 15.6 20.1
NaF 9.3 3.6
AlPO4 3.8 12.8
• The raw materials are fused to a uniform glass by heating them to a
temp.of 1100 °C- 1500°C.
• Lanthanum,strontium,barium or zinc oxide additions provide radio
• The glass is ground into a powder having particles in the range of 15-
•ROLE OF COMPONENTS IN POWDER
•The role of Al2O3 & SiO2 of the glass is crucial and is required to be of
1:2 or more by mass for cement formation.
•CaF2-Supplemented by the addition of cryolite (Na3AIF6).
-reduces the temperature at which the glass will fuse
-increases the translucency of the set cement.
• Fluoride is an essential constituent which
- Lowers fusion temp., acts as flux
- improves working characteristics & strength
- improves translucency
- improves therapeutic value of the cement by
releasing fluoride over a prolonged period
• Al3PO4-Improves translucency.
Apparently adds body to the cement paste
• The liquid is an aqueous solution of polymers
andcopolymers of acrylic acid.
• In most of the current cements,the acid in the form of a
coploymer with itaconic ,maleic ,or tricarboxylic acids.
• polyacrylic acid-is the most important acid contributing to
formation of the cement matrix.
• It is reaction medium.
• It serves to hydrate the siliceous hydrogel and the metal
• 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.
•Glass ionomer cements are water-based materials
•Plays a role in transporting calcium and aluminium ions to react with
- Lossely bound water
-Tightly bound water
•With the aging of cement, the ratio of tightly bound to loosely bound
•Accompanied by an increase in strength, modulus of elasticity and
decrease in plasticity
•Cement is only stable in an atmosphere of 80% relative humidity
• In higher humidities the cement absorbs water and the consequent
hygroscopic expansion can exceed the setting shrinkage.
• Cement can lose water under drying conditions, however leading to
shrinking and crazing.
• Susceptibility to desiccation decreases as the cement ages
• This is prevented if protected for about 10 to 30 mins (depends on
• ITACONIC ACID
• Itaconic acid promotes reactivity between the glass and the liquid.
• It also prevents gelation of the liquid which can result from
hydrogen bonding between two polyacrylic acid chains
• A stronger acid than polyacrylic acid
• Causes the cement to harden and lose its moisture
• More carboxyl (COOH) groups which lead to more rapid
• Tartaric acid
• The 5% optically active dextro-isomer of tataric acid is
• It is also hardener that controls the PH of the set cement during
setting process, which in turn controls the rate of dissolution of the
• It facilitates extraction of ions from the glass.
• It typically increases the working time and also aids in snap test.
A.ACCORDING TO A.D. WILSON AND J.W.McLEAN IN
Type I --- luting cements
Type II --- restorative cements
B. ACCORDING TO SKINNERS
Type I – Luting
Type II- Restorative
Type III- Liner and base
C. ACC.TO CHARACTERISTICS SPECIFIED BY
• Type I --- Luting cement eg. Fuji I, KETAC
• Type II --- Restorative material eg. Ketacfil, Fuji II, fuji IX
• Type III --- a. Bases & liners
• Type IV --- Admixture --- eg. Ketac silver, miracle mix
D. ACCORDING TO J.W.McLEAN et al IN 1994
- Glass ionomer cement (traditional)
-Resin modified glass ionomer cement
-Poly acid modified composite resins
E. ACCORDING TO INTENDED APPLICATIONS
• Type I – Luting
• Type II – Restorative
• Type III – Liner/base
• Type IV – Pit & fissure sealant
• Type V – Luting for orthodontic purpose
• Type VI – Core buildup material
• Type VII – High fluoride releasing command set
• Type VIII – Atraumatic restorative treatment
• Type IX − Pediatric Glass Ionomer cements
F. NEWER CLASSIFICATION
• Traditional glass ionomer
a. Type I --- Luting cement
b. Type II --- Restorative cements
c. Type III --- Liners&Bases
• Metal modified Glass Ionomer
a. Miracle mix
b. Cermet cement
• Light cure Glass Ionomer
HEMA added to liquid
• Hybrid Glass Ionomer/resin modified Glass Ionomer
a.Composite resin in which fillers substituted with glass
b.Precured glasses blended into composites
Conditioning the Tooth Surface
• Dentin conditioning prior to placement of a GIC is done primarily
to remove the smear layer.
•GIC is better able to wet the dentin surface.
•Promotes ion exchange.
•Chemically cleans dentin.
•Increases surface energy.
Surface treatment Time of application(sec)
Citric acid, 50% aq 30
Citric acid, 2% aq/alc 30
Poly (acrylic acid), 25% aq 30
Tannic acid, 25% aq 60
Surface-active solution 60
Dodicin, 0.9% aq 60
Na2EDTA, 2% aq 30
Na2EDTA, 15% aq 30
Sodium flouride, 3% aq 30
Ferric chloride, 2% aq/alc 30
Mixing of the cement
Full spoon, no excess
Tip liquid bottle to side, then
If water / tartaric acid, only 1 drop
Liquid should not stay on paper pad longer
than 1minute (some of it may soak into it)
Don’t mix beyond 30 seconds
The objective is – only wet the particle – no
First half folded into liquid in 10-15seconds
Second half incorporated in 15 seconds
Small mixing area
Loss of gloss/ slump test
GIC --- 60 – 90 sec
Resin-modified GIC --3 – 3.5 min
Working time & setting time
• It sets rapidly in the mouth that is within 3-5 min and hardens to
form a body having translucency that matches enamel
• Setting time for type I –GIC – 5 -7 min
• Setting time for type II–GIC --10 min
• Film thickness should not exceed 20µm for luting agents
• To activate capsule apply
pressure 3-4 seconds
before placing in machine
• Ultrahigh speed machine :
• Best surface –cement allowed to set under matrix
•Carving the cement external to the cavity margins with
sharp knives or scalers
•Finest abrasive should be used to minimize tearing
•Finishing with rotary instruments should be done at
•1. acid-base reaction
•2. light activated polymerisation
• ACID – BASE REACTION
• GIC formed by the reaction of three materials
Fluoro alumino silicate glass powder
Poly acrylic acid
• An acid – base reaction occurs between the glass powder and
the ionic polymer.
• Water is essential because that is the medium through which
ion transfer takes place
• Chemistry of cement forming reaction from initial mixing
occurs in various stages
• The glass particles are attacked at the surface by poly acid which
leads to withdrawal of the cations thus the glass network breaks down
to silicic acid.
• Principally Al3+, Ca2+, F-, are released and migrate into aqueous
phase of cement and form complexes
Decomposition of glass & migration of ions
• Initially calcium complexes predominate but later Aluminium
complexes are more.
• pH and viscosity increases
• At critical pH and ionic conc. Precipitation of insoluble poly acrylates
• Initial set occurs due to calcium polyacrylate but hardening of cement
is due to slow formation of aluminium polyacrylate
• When cement is not fully hardened Al, Ca, F and polyacrylate ions
may leach out leading to irretrievable loss of cement matrix
• Calcium acrylate is more vulnerable to water. So the
freshly set cements are to be protected.
• This process continues for about 24 hrs
• Undergoes slight expansion and increase in translucency
• Cement becomes resistant to dessication and strength also
increases for at least a year
•Increase in strength and rigidity are associated with slow increase
in cross linking.
Mechanism of adhesion
• Polyalkenoic acid attacks dentine and enamel: displaces PO4,Ca
• Migrate into cement and develop an ion enriched layer firmly
attached to tooth structure.
• The bond strength to enamel is always higher than that to
dentin because of the greater inorganic content & greater
• Smith – chelation of calcium(1968)
• Beech –
interaction between apatite and poly acrylic
Ionic bonds with calcium ions in enamel and dentin
• Acc. to Wilson(1974)
• Initial adhesion is by hydrogen bonding from free carboxylic
• Progressively these bonds are replaced by ionic bonds
• Polymeric polar chains of acids bridge the interface
between cement and substrate
• Acc. to Wilson, Prosser and Powis(1983)
• Polyacrylate displaces and replaces surface phosphate and
calcium from hydroxyapatite
• An intermediate layer of Ca and Al phosphates and
polyacrylates is formed.
• Resistance to plaque because presence of F
• Pulp response to GIC is favorable
• Freshly mixed --- acidic pH 0.9 – 1.6 -- mild inflammation resolve
10 -20 days
* used to protect mech / traumatic exposure of healthy pulp
• Glass ionomer cement showed greater inflammatory response than
ZOE but less than Zn phosphate cement & other cements but it
resolved in 30 days
(Garcia et al, 1981)
• The influence of fluoride action is seen of at least 3 mm
around the glass ionomer restoration
• Released for a sustained period of 18 months (Wilson et al
• Thickly mixed cements release more flouride than thinly
• Glass ionomers may have synergistic effects when used
with extrinsic fluorides
• In the presence of an inverse fluoride concentration
gradient, glass ionomers may absorb fluoride from the
environment and release it again under specific conditions
• topical APF (acidulated phosphate fluoride), with fluoride
rinses and fluoridated dentifrices recharging takes place
• Glass ionomer cement has got a degree of translucency
because of its glass filler
• Unlike composite resins, glass ionomer cement will
not be affected by oral fluids
• The esthetic quotient depends upon
1.Refractive index of glass particles and matrix
3.translucency of glass particles
• Specification limits of GIC 0.35 -.90 (for optimum aesthetics
it is between 0.35 – 0.90 )
Affected by the factors
• Inadequate preparation of the cement
• Inadequate protection of restoration
• Variable conditions of mouth
Failure rate is more a measure of clinician’s skill than
inherent quality of the material
• One of the longest observation periods for the conventional
glass ionomers in non-carious cervicallesions showed
retention in the order of 90% after 10 yrs for KetacFil
• Some other properties
• Low exothermic reaction
• Adheres chemically to the tooth structure
• Less shrinkage than polymerizing resins
• Dimensional stability at high humidity
• F release discourages microbial infiltration
• Early moisture sensitive --- requires protection
• Poor abrasion resistance
• Average esthetic
• 1. Restorative materials:
• Restoring of erosion/ abrasion lesions without cavity
• 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.
• Repair of defective margins in restorations
• Minimal cavity preparations – Approximal lesions, Buccal and
Occlusal approach (tunnel preparation)
• Core build-up
2. Fast setting lining cement and bases:
• Lining of all types of cavities where a biological seal and
cariostatic action are required
• replacement of carious dentin 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 Cements are used.
• Useful in patients with high caries index
• Devolped by Mclean,
• To combine the beneficial properties of GIC & composite.
Clinical steps:-Clinical steps:-
•After cavity preparation,
condition the cavity to develop
good adhesion with GIC.
•Place Type III GIC into prepared
•After setting, etch the enamel &
GIC with phosphoric acid for 15
•This will improve
micromechanical bond to
•Apply a thin layer of low viscosity
dentin bonding agent & finally
place the composite resin over
GIC & light cure it.
• Polymerisation shrinkage is less,due to reduced bulk
• Favorable pulpal response.
• Chemical bond to the tooth.
• Anticariogenic property.
• Better strength,finishing,esthetics of overlying
• Microleakage is reduced
• Minimization of no. of composite increments,
therefore time is saved
GIC IN ENDODONTICS
They are used for:
• Sealing root canals orthogradely , retrogradely
• Restoring pulps chamber
• Perforation repair
• Sometimes for repairing vertical fracture
GIC was used because of :
• Its capacity to bond which enhances seal & reinforce the tooth
• Its good bio compatibility, which would minimize irritation to
peri radicular tissues
• Its F release, which imports an anti microbial effect to combat
root canal infection
• Class IV carious lesions or 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.
Modifications of GIC
1.1.WaterWater settable glasssettable glass ionomer cement :-ionomer cement :-
• Liquid is delivered in a freeze dried form ,which is
incorporated into the powder.
• Liquid used is clean water.
2.The low viscosity/flowable GIC –
• For lining, pit and fissure sealing
• endodontic sealers
• for sealing of hypersensitive cervical areas
These had a low P:L ratio and possessed increase flow.
eg: Fuji lining LC, Fuji III and IV, Ketac – Endo.
METAL MODIFIED GIC
MIRACLE MIX / SILVER ALLOY ADMIX GIC
• Sced and Wilson in 1980 incorporated spherical
silver amalgam alloy into Type II GIC powder in
a ratio of 7:1
• Glass –17.5%
• Silver –82.5%
Particle size of silver is 3 – 4µm
• Aqueous solution of copolymer of acrylic acid and
or maleic acid—37%
• Tartaric acid 9%
• Resistant to burnishing
• Poor aesthetics
• Also called as cermet ionomer cements
• McLean and Gasser in 1985 first developed
• Fusing the glass powder to silver particles through sintering
that can be made to react with polyacid to form the cement
• Sintering is done at high pressure more than 300MPa and at
a temperature of 8000
C which is ground to fine powder
particle size of 3.5 µm
• 5%titanium dioxide is added to improve aesthetics
• It has excellent handling characteristics
• Core build –up material
• Root caps of teeth under over dentures
• Class I cavities.
• Preventive restoration
• Temporary posterior restoration
• Anterior restorations.
• Areas subjected to high occlusal loading
• Both tensile and compressive strength is greater
than conventional glass ionomer cement
Modulus of elasticity-
• tends to be relatively lower than conventional GIC
• greater than conventional GIC due to silver particle
silver cermet radio opacity is equal to that of dental
Type II cermet miracle mix
• 2 weeks 440 mg 200 mg 3350mg
• 1 months 650 mg 300 mg 4040 mg
RESIN MODIFIED GLASS IONOMER
• developed by Antonucci, Mc Kinney and SB Mitra.
• Addition of polymerizable resins to the formulation to import
additional curing process to the original acid base reactions.
Definition: RMGIC can be defined as a hybrid cement that sets via
an acid base reaction and partly via a photo- chemical
Eg:Fuji II LC, Vitrebond, Photac –Fil, Vitremer, FujiV.
• Powder: Ion leachable glass and initiators for light /
chemical / both types of curing
• Liquid : water + Polyacrylic acid modified with HEMA
• The HEMA content is around 15-25% and water
content is low to accommodate the polymerizable
• It is a powder : liquid system with P:L = 3:1
2 distinct setting reactions occur
• Acid base neutralization
• Free radicle cure. This can occur purely via light
cure or by a combination of LC and chemical cure.
• Thus a cement can be termed
- dual cure if cross linking is via acid base + LC or
- tri cure if its via acid base + Light cure + chemical
• Esthetics: According to the latest Skinners, there is a
definite improvement in translucency as the
monomer brings the refractive index of the liquid
close to that of the glass particle.
• Fluoride release: is same as that of the conventional
but the lining version shows higher F release
• Strength: The diametrical tensile strength is much
higher but compressive strength and hardness is lesser.
• Adhesion: to tooth is reduced. This is expected because of
reduction in carboxylic acid in the liquid and interruption of
chemical bonding due to the resin matrix.
-Adhesion to composites is increased due to the presence of
residual non-polymerized functional groups within the
• Micro leakage: A higher degree of Microleakage is
seen due to polymerization shrinkage
• also due to reduced water and carboxylic acid content and
reduces its wetting capacity
• Water sensitivity is considerably reduced.
• The biocompatibility is controversial and precautions
such as placing Ca (OH)2 in deep preparations should
be taken. The transient t0
rise during setting is also a concern
• Luting cement esp in orthodontics
• Liner and base
• Pit and fissure sealant
• Core build up material
- For amalgam repair
• Long Working time and Snap setting
• Early water sensitivity is reduced
• Rapid development of early strength
• No etching is needed either to tooth for adhesion or for
the material if composite lamination is to be done.
• Bonding to composite is higher
• Finishing can be done immediately
• F release
• Diametrical tensile strength is higher
• Of course some drawbacks still need to be
tackled such as
increased shrinkage with concurrent microleakage
Low wear resistance as compared to composites
Its controversial biocompatibility
Glass ionomer cement by Alan D.Wilson and John W. Mclean
Philips science of dental materials, Eleventh edition
Sturdevant’s Art and science of operative dentistry, Fifth edition
Craig’s Restorative dental materials, Twelfth edition
G J Mount and R W Hume Text book of Minimal intervention
Advances in Glass ionomer cement , Carel L. Davidson, J Minim
Interv Dent 2009; 2 (1)
Clinical evaluation of glass-ionomer Cement restorations, Martin
John TYAS J Appl Oral Sci. 2006;14(sp.issue):10-3