Glass Ionomer Cement

1. NAME- SK AZIZ IKBAL
Dept. of Conservative Dentistry &
Endodontics
TYPES OF GLASS IONOMER
CEMENT & IT's ADVANCEMENTS
NORTH BENGAL DENTAL
COLLEGE & HOSPITAL

2. Glass ionomer cement is a tooth coloured material,
introduced by Wilson & Kent in 1972.Material was based on
reaction between silicate glass powder & polyacrylic
acid.They bond chemically to tooth structure & release
fluoride for relatively long period.
 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.
Glass ionomer cement is a basic glass and an acidic
polymer which sets by an acid- base reaction between these
components”
INTRODUCTIONINTRODUCTION

3. CLASSIFICA
TION
 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 PHILIPS
Type I – Luting
Type II- Restorative
Type III- Liner and base

4. C. 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

5. D.ACCORDING TO CLINICAL USE AS:
 Type I- Luting
 TYPE II- Restorative
 Type III-Fast setting Liner/ Base
 Type IV- Pit & Fissure Sealant
 Type V- Orthodontic cements
 Type VI- Core build up material
 Type VII- Glass ionomer cermet cement(a. Silver b.Gold)
 Type VIII-GIC for ART(Resin modified GIC)
 Type IX- GP GIC (Geriatric & Paediatric GIC)

6. E. ACCORDING TO STURDVENT:
 1. Traditional or conventional
 2. Metal modified GIC
a. Cermet
b. Miracle Mix
 3. Light cured GIC
 4. Hybrid (Resin modified GIC)
 5. Polyacid modified resin composites or
Compomer

7. COMPOSITION
Powder :-Powder :-
Acid soluble calcium fluroalumino silicate glass.
Silica - 41.9%
Alumina - 28.6%
Aluminum fluoride - 1.6%
Calcium fluoride - 15.7%
Sodium fluoride - 9.3%
Aluminum phosphate - 3.8%
Fluoride portion act as ceramic flux. Strontium,
Barium or zinc oxide provide radio opacity.
Liquid :-Liquid :-
1.Polyacrylic acid in the form co-polymer with itaconic acid & maleic acid .
2.Tartaric acid: improves handling characteristic
& increase working time.
3.Water : Medium of reaction & hydrates the
reaction products

8. SETTING
REACTION
The acidic liquid solution (pH=1)
dissolves portions of the periphery
of the silicate glass particle,
releasing calcium, aluminum,
fluoride, silicon and other ions.
The calcium are chelated quickly by
carboxyl side groups on polyacrylic acid polymer chains
Cross-linking of the poly acrylic acid chains takes place producing
an amorphous polymer gel

9. During the next 24-72 hours, the calcium ions are replaced by
more slowly reacting aluminum ions to produce a more highly
cross-linked matrix that is now mechanically stronger
It is now believed that during the maturation involving aluminum
ion cross-linking, silicon ions and unbound water participate in
producing an inorganic co-matrix, best described as a hydrated
silicate
The same carboxylic acid side group also are capable of chelating
surface ions on the calcium ions from the tooth structure
The process generates true chemical bonds at all internal and
external interfaces when the reaction conditions are correct.

10. SETTING TIME
Type I 4 - 5 minutes
Type II 7 minutes
PROPERTIES
Compressive strength - 150 mpa
Tensile strength - 6.6 mpa.
Hardness - 49 KHN.

11.  Initial solubility is high due to leaching of intermediate
products.
 The complete setting reaction takes place in 24 hrs, cement
should be protected from saliva during this period.
Adhesion :-
 Glass ionomer cement bonds chemically to the tooth structure.Glass ionomer cement bonds chemically to the tooth structure.
 Bonding is due to reaction occur between carboxyl group of poly
acid & calcium of hydroxyl apatite.
 Bonding with enamel is higher than that of dentin ,due to greater
inorganic content.
Solubility & Disintegration:-

12. Biocompatibilty :-
 Pulpal response to glass ionomer cement is favorable.
 Pulpal response is mild due to
- High buffering capacity of hydroxy apatite.
- Large molecular weight of the polyacrylic
acid ,which prevents entry into dentinal tubules.
Esthetics :-
 GIC is tooth coloured material & available in different
 shades.
 Inferior to composites.
 They lack translucency & rough surface texture.
 Potential for discolouration & staining.

13. Anticariogenic properties :-
 Fluoride is released from glass
ionomer at the time of mixing &
lies with in matrix. Fluoride can be
released out without affecting the
physical properties of cement.
Initial release is high. But declines
after 3 months.
After this, fluoride release continuous
for a long period.
Fluoride can also be taken up into the
cement during topical fluoride
treatment and released again ,thus
GIC act as fluoride reservoir.

14. MM-GIC
GIC and
-Metallic fillers
-Cermet fillers
CORES
GIC
(Original material)
CEMENTS
RR-GIC
GIC and
Resin fillers
ART-GIC &
TEMPORARIES
RM-GIC
GIC and
-VLC hydrophilic
monomer and
polymer
CEMENTS
COMPOSITE
CEMENTS
FILLING MATERIAL
COMPOMER
VLC composite and F
source
FILLING
MATERIALS
GIOMER
VLC composite and
Pre-reacted GIC powder
FILLING MATERIAL
Summary of the historical evolution of Glass Ionomer Cements

15. The main shortcoming of GIC that limits its use in stress bearing areas is
its lack of fracture toughness. To improve upon it metal reinforced
GICs were developed.
They are mainly of two types:
1. MIRACLE MIXTURE
2. CERMET MIXTURE
METAL MODIFIED GIC
• Seed & Wilson (1980) invented Miracle Mixture: Spherical silver amalgam
alloy+Type II G I C in ratio 7:1
• Mc lean & Gasser (1985) invented Cermet Mixture.

16. Miracle Mixture
•This is made by mixing of spherical silver amalgam alloy powder with glass
ionomer powder.
•This combination became known as the miracle mixture because it was
initially introduced during the early 1980s at the time when the mercury
controversy was increasing dentists’ questions about the safety of amalgams.
•Miracle mixture was far inferior to those of amalgam, so it was not well
received as restorative material.
•Main problem was that the matrix would not adhere to strongly to the
silver- tin alloy particles

17. Cermet Mixture
CERMET MIXTURE: Ceramic-Metal Mixture
•To circumvent the previous mentioned difficulty, the silver-tin
alloy particles were substituted by Silver-palladium(Ag-Pd),
which generate passivation of oxide film of palladium oxide that is
chemically reactive by chelation with polyacrylic acid.
•Stronger than unmodified glass ionomer cements but had poor
esthetics.
•Used mostly as cores

18. • Indications:
• Class I cavities in primary teeth
• Core build up material
• Lining of class II amalgam restorations
• Root caps for teeth under over dentures
• As a preventive restoration
• Contraindications:
• Anterior restoration
• In areas of high occlusal loading

19. Advantages:
•Ease for placement
•Adhesion to tooth structure and
anticariogenic potential
•Crown cutting can be done immediately
•Increased wear resistance
Disadvantages:
•Esthetically poor
•Tooth discoloration
•Rough surface
•Reduced W.L and S.T

20. RESIN MODIFIED GIC(RMGIC)
• To overcome low early strength and moisture sensitivity
• Defined as HYBRID CEMENT that sets partly by acid base reaction and
partly by polymerisation reaction (Mc Lean)
• Materials that are modified by the inclusion of resin, generally to make the
them more photo curable (Nicholson)
• Usually light cured, less technique sensitive and may be finished at the time
of placement.
• Esthetic – Superior than conventional GIC
• Because RMGIs are significantly stronger than traditional glass ionomers,
they are recommended for class V restorations and can be used for class I
and class II restorations in primary teeth

21. Advantages
• Long working time due to photo curing
• Improved setting characteristics
• Decrease sensitivity to water
• Increase early strength
• Finishing & polishing can be done immediately
• Improved tensile strength.
• Better adhesion to composite restoration
• Increase fluoride release.
• Repairable.
Disadvantages
• Biocompatibility is controversial
• More setting shrinkage leading increase microleakage and poor marginal
adaptation

22. POLYACID MODIFIED
COMPOSITE RESIN
• Also called as COMPOMER
• Defined as : material that contain both the essential
components of GIC but in an amount insufficient to carry
out acid base reaction in dark.
• They are developed to combine fluoride release of GIC
and durability of composite

23. POLYACIDMODIFIEDRESIN COMPOSITE /
COMPOMER

24. Properties
• Adhesion –Micromechanical, absence of water thus no self adhesion
• Fluoride release minimal.
• Physical properties better than conventional GIC but less than composite.
• Optical properties superior to conventional GIC.
Uses
Pit and fissure sealant
• Restoration of primary teeth
• Liners and bases
• Core build up material
• For class III & V lesions
• Cervical erosion / abrasion
• Repair of defective margins in restorations
• Sealing of root surfaces for over dentures
• Reterograde filling material.

25. Contraindications
• Class IV carious lesions
• Large areas of labial surfaces
• Class II cavities where conventional cavity is prepared
• Lost cusp areas
• Under full crown or PFM crowns.
Advantages
• Ease of use
• Easy adaptation to the tooth
• Good esthetics
• More working time than RM GIC

26. FIBER-REINFORCED GLASS IONOMER
CEMENTS• Incorporation of alumina fibres into the glass powder to improve upon its
flexural strength
• This technology called the Polymeric Rigid Inorganic Matrix Material or PRIMM
developed by Dr. Lars Ehrnsford
• It involves incorporation of a continuous network of alumina and SiO2 ceramic
fibres
Advantages:
• Increased wear resistance.
• Improved handling characteristics
• Increased depth of cure
• Reduction of polymerization shrinkage
• Improved flexure strength(50Mpa)

27. GIOMER
True hybridization of GIC and composite . But here pre-reacted GIC
powder is dispersed phase within compomer.
Combine fluoride release and fluoride recharge of GIC
esthetic & easy polishable
INDICATIONS
• Class I, II, III, IV, and Class V cavities
• Restoration of cervical erosion and Root caries
• Laminates and core build up
• Restoration of primary teeth.
• Repair of fracture of porcelain and composites

28. • To summarize the differences between the three
types of materials:
• Fluoride Release ability
GICs>RMGICs>PAMCRs
• Wear Resistance
PAMCRs>GICs>RMGICs
• Strength
PAMCRs>RMGICs>GICs
• Ease of Handling
PAMCRs>RMGICs>GICs
• Polishability and Esthetics
PAMCRs>RMGICs>GICs

29. REFERENCESREFERENCES
• Glass ionomer cement by Alan D.Wilson and John W.
Mclean
• Philips science of dental materials, 11th
ed & 12th
ed
• Sturdevant’s Art and science of operative dentistry, Fifth
edition