This document discusses glass ionomer cement, including its definition, history, composition, properties, applications, and mechanisms. Glass ionomer cement is formed from a reaction between glass powder and a polyacrylic acid liquid. It sets rapidly, bonds chemically to tooth structure, and has favorable biocompatibility. Its properties make it useful for applications such as luting, liners, temporary restorations, and sealing pits and fissures.

1. GLASS IONOMER CEMENT
MATERIAL ASPECT
SAGAR HIWALE
1st
yr PG
Dept. of conservative dentistry &
endodontcs
JAIPUR DENTAL COLLEGE

2. CONTENT
1.DEFINITION.
2.HISTORY.
3. SYNONYMS.
4.COMPOSITION.
5.CLASSIFICATION.
6.CEMENT PLACEMENT.
7.MIXING OF CEMENT.
8. WORKING TIME AND SETTING TIME.
9.SETTING REACTION.
10.PROPERTIES OF GLASS IONOMER CEMENT.
11.INDICATIONS.
12CONTRAINDICATIONS.
13.ADVANTAGES.
14.DISADVANTAGES
15.USES
16. MODIFICATIONS OF GIC.
17. REFERENCES

3. Definition
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.

4. History
•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
tartaric acid.
• ASPA III- Methyl alcohol was added.
• First marketable material, ASPA IV in 1973
• Luting agent ASPA IVa in 1975 by Crisp and Abel

5. •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.

6. synonyms
• 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
Dentin substitute
Man made dentin
Artificial dentin
•Introduced into u.s as ASPA-Alumino silicate polyacrylate

7. Composition
• 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

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
opacity.
• The glass is ground into a powder having particles in the range of 15-
50 µm.
•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).
•This flux
-reduces the temperature at which the glass will fuse
-increases the translucency of the set cement.

9. • 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

10. •LIQUID
•Polyacrylic acid --- 45 %
•Water --- 50 %
•Modifiers Iticonic acid --- 05 %
maleic acid
tricarballylic acid
viscosity ,inhibits gelation , shelf life.
•Tartaric acid --- Working Time & setting time.

11. • 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.
• Water-
• 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.

12. •Glass ionomer cements are water-based materials
•Plays a role in transporting calcium and aluminium ions to react with
poly acids.
•Types:
- Lossely bound water
-Tightly bound water
•With the aging of cement, the ratio of tightly bound to loosely bound
water increases
•Accompanied by an increase in strength, modulus of elasticity and
decrease in plasticity
•Cement is only stable in an atmosphere of 80% relative humidity

13. • 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
manufacturer).
• 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

14. • A stronger acid than polyacrylic acid
• Causes the cement to harden and lose its moisture
sensitivity faster.
• More carboxyl (COOH) groups which lead to more rapid
polycarboxylate crosslinking
Maleic acid

15. • Tartaric acid
• The 5% optically active dextro-isomer of tataric acid is
incorporated.
• 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
glass.
• It facilitates extraction of ions from the glass.
• It typically increases the working time and also aids in snap test.

16. CLASSIFICATION
A.ACCORDING TO A.D. WILSON AND J.W.McLEAN IN
1988
Type I --- luting cements
Type II --- restorative cements
a.Restorative aesthetic
b.Restorative reinforced
B. ACCORDING TO SKINNERS
Type I – Luting
Type II- Restorative
Type III- Liner and base

17. C. ACC.TO CHARACTERISTICS SPECIFIED BY
MANUFACTURER
• 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

18. 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

19. 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
ionomer particles
b.Precured glasses blended into composites

20. Cement placement
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.

21. Agents used
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

22. Mixing of the cement
Full spoon, no excess
Tip liquid bottle to side, then
invert completely
If water / tartaric acid, only 1 drop
used.

23. 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
dissolving it.
First half folded into liquid in 10-15seconds
Second half incorporated in 15 seconds
Small mixing area

24. Loss of gloss/ slump test
GIC --- 60 – 90 sec
Resin-modified GIC --3 – 3.5 min

25. 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

26. Mixing capsules
• To activate capsule apply
pressure 3-4 seconds
before placing in machine
• Ultrahigh speed machine :
4000 cycles/minute

27. Finishing technique
• 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
subsequent visit

28. Setting reaction
•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
Water
• 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

29. • 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

30. • 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
takes place.
• Initial set occurs due to calcium polyacrylate but hardening of cement
is due to slow formation of aluminium polyacrylate

31. • 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

32. •Increase in strength and rigidity are associated with slow increase
in cross linking.

35. Mechanism of adhesion
• Polyalkenoic acid attacks dentine and enamel: displaces PO4,Ca
ions
• 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
homogenity.

36. MECHANISM
• Smith – chelation of calcium(1968)
• Beech –
interaction between apatite and poly acrylic
acid
polyacrylate ions
Ionic bonds with calcium ions in enamel and dentin

37. • Acc. to Wilson(1974)
• Initial adhesion is by hydrogen bonding from free carboxylic
groups
• 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.

38. Properties of Glass Ionomer cement
luting cement
PROPERTY VALUES
1.Setting time(min) 7.0
2.Film thickness(µm) 24
3.24 hr compressive strength(Mpa) 86
4.24 hr diametrical tensile
strength(Mpa)
6.2
5.Elastic modulus(Gpa) 7.3
6.Solubility in water(Wt%) 1.25
7.Pulp response Mild to moderate

39. Restorative cements
PROPERTY GLASS IONOMER
II
CERMET HYBRID
IONOMER
1.Compressive
strength(Mpa)
150 150 105
2.Diametrcal
tensile
strength(Mpa)
6.6 6.7 20
3.Knoop
hardness(KHN)
48 39 40
4.Pulp response mild mild mild

40. •Biocompatibility
• 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)

41. • 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
1985)
• Thickly mixed cements release more flouride than thinly
mixed ones.
Fluoride release

42. Fluoride recharge
• 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

45. • ESTHETICS
• 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

46. • The esthetic quotient depends upon
1.Refractive index of glass particles and matrix
2.Particle size
3.translucency of glass particles
• Specification limits of GIC 0.35 -.90 (for optimum aesthetics
it is between 0.35 – 0.90 )

47. Durability
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

48. • 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

49. 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.
• Repair of defective margins in restorations
• Minimal cavity preparations – Approximal lesions, Buccal and
Occlusal approach (tunnel preparation)
• Core build-up

50. 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

51. Tunnel preparation

52. Sandwich technique
• 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
cavity.
•After setting, etch the enamel &
GIC with phosphoric acid for 15
seconds.
•This will improve
micromechanical bond to
composite resin.
•Apply a thin layer of low viscosity
dentin bonding agent & finally
place the composite resin over
GIC & light cure it.

53. Advantages
• Polymerisation shrinkage is less,due to reduced bulk
of composite.
• Favorable pulpal response.
• Chemical bond to the tooth.
• Anticariogenic property.
• Better strength,finishing,esthetics of overlying
composite resin.
• Microleakage is reduced
• Minimization of no. of composite increments,
therefore time is saved

54. 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

55. Contra indications
• 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.

56. 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.

57. 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
Powder
• Glass –17.5%
• Silver –82.5%
Particle size of silver is 3 – 4µm
Liquid
• Aqueous solution of copolymer of acrylic acid and
or maleic acid—37%
• Tartaric acid 9%

58. Disadvantages
• Resistant to burnishing
• Poor aesthetics

59. GLASS CERMET
• 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

60. Indications
• Core build –up material
• Root caps of teeth under over dentures
• Class I cavities.
• Preventive restoration
• Temporary posterior restoration
Contraindications
• Anterior restorations.
• Areas subjected to high occlusal loading

61. PROPERTIES
Strength-
• Both tensile and compressive strength is greater
than conventional glass ionomer cement
Modulus of elasticity-
• tends to be relatively lower than conventional GIC
Abrasion resistance-
• greater than conventional GIC due to silver particle
incorporartion

62. Radiopacity:
silver cermet radio opacity is equal to that of dental
amalgam
Fluoride release
Type II cermet miracle mix
• 2 weeks 440 mg 200 mg 3350mg
• 1 months 650 mg 300 mg 4040 mg

63. RESIN MODIFIED GLASS IONOMER
CEMENTS

64. RESIN MODIFIED GLASS IONOMER
CEMENTS
• 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
polymerization reaction.
Eg:Fuji II LC, Vitrebond, Photac –Fil, Vitremer, FujiV.

65. Composition
• Powder: Ion leachable glass and initiators for light /
chemical / both types of curing
• Liquid : water + Polyacrylic acid modified with HEMA
monomers.
• The HEMA content is around 15-25% and water
content is low to accommodate the polymerizable
ingredients.
• It is a powder : liquid system with P:L = 3:1

66. Setting reaction
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
cure

67. properties
• 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.

68. • 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
RMGIC
• 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

69. • 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

70. INDICATIONS
• Luting cement esp in orthodontics
• Liner and base
• Pit and fissure sealant
• Core build up material
- For amalgam repair
ADVANTAGES
• Long Working time and Snap setting
• Early water sensitivity is reduced
• Rapid development of early strength

71. • 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
• DRAWBACKS
• 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

72. • References
 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
dentistry
 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