Glass ionomer cement was introduced in 1970 as a tooth-colored luting and restorative material. It bonds chemically to enamel and dentine, is esthetic, and releases fluoride over time which is anticariogenic. However, glass ionomer cement is also brittle and susceptible to erosion and wear. When mixed, the acid in the liquid attacks the glass powder, releasing calcium, aluminum, and fluoride ions to cross-link with polyacrylic acid chains and form the cement matrix. The set cement has unreacted glass particles embedded in a hydrated calcium/aluminum polyacrylate gel. It is important to protect the sensitive cement from moisture during setting for 24 hours to allow full hardening.

1. By;
Mhmood M.H. Radhi
BDS
Final year

2. • Glass ionomer cement is a tooth colored
material, introduced by Wilson et al in 1970.
• It can be used as luting cements or lining
under another restoration or as restorative
material.

3. Type
I.
Type
II.
For luting
For restoration
Type II.1 Restorative esthetic
Type II.2 Restorative reinforced
Type III. For liner & bases

5. Powder :It is an acid soluble calcium fluroalumino silicate glass.
Silica
Alumina
Aluminum fluoride Calcium fluoride
Sodium fluoride
Aluminum phosphate -
41.9%
28.6%
1.6%
15.7%
9.3%
3.8%

6. Liquid :1.Polyacrylic acid in the form co-polymer with itaconic acid
& malic acid .
2.Tartaric acid: improves handling characteristic
& increase working time.
3.Water : Medium of reaction & hydrates the
reaction products

7. When the powder &
liquid are mixed,
Surface of glass
particles are
attacked by acid.
then Ca, Al,
sodium, & fluoride
ions are leached
into aqueous
medium.

8. Calcium ion cross-link the poly acrylic acid chains,
This forms a solid mass.
In next phase, aluminum also begins to cross-link
with poly acrylic acids chains.
Water plays an important role in structure of
cement. Initially it serves as the medium, later it
slowly hydrates the matrix.
The unreacted glass(powder) particle is covered by
a silica gel.

9. 


The set cements consists of agglomeration of
unreacted powder particles surrounded by a silica gel
sheath and embedded in a matrix of hydrated calcium
and aluminum cross-liked poly acrylic gel.
The exposure of cement to water before hardening is
complete, leads to loss of cations and anions which
form a matrix as they can be dissolved.
Thus it is very important to protect the cement surface
after its placed in the mouth e.g. by applying a varnish

10. 
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.

11. Adhesion :☻ It adheres well to enamel and dentine.
☻ Glass ionomer cement bonds chemically to the tooth
structure.
Esthetics :GIC is tooth colored material & available in different
shades.
Inferior to composites.
They lack translucency & rough surface texture.
It may be stain with time.

12. Biocompatibility : The GIC show high degree of compatibility with living
tissue.
 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.
Anticariogenic properties :-
•Fluoride is released from glass ionomer at the time of
mixing & lies with in matrix.

13. 1.Preparation of tooth surface :2.Proportioning & mixing : Powder & liquid ratio is 3:1 by wt. Powder & liquid is
dispensed just prior to mixing.
 First increment is incorporated rapidly into the mix with
stiff bladed spatula.
 Mixing done in folding method to preserves gel
structure.
 Finished mix should have a glossy surface.
 Stiff mixing spatula is preferred.

14. 3. Protection of cement during setting : GIC is extremely sensitive to air and water during
setting.
 It should be protected from moisture as well as drying
during setting for few days.
4. Finishing : Excess material should be trimmed from margins.
 Hand instruments are preferred to rotary tools to avoid
ditching.
 Further finishing is done after 24hrs.

15. 5.Protection of cement after setting :

Before dismissing the patient ,restoration is again
coated with the protective agent to protect trimmed
area.
Failure to protect for first 24hrs results in weaken
cement.

17. ♣
♣
♣
Adhesive
Esthetic
Fluoride releasing
Disadvantages:♦
♦
Susceptible to erosion and wear
brittle

18. 1.Anhydrous GIC : Liquid is delivered in a freeze dried form ,which is
incorporated into the powder.
 Liquid used is clean water.
2.Resin modified GIC:GIC
Powder component consist of ion leachable fluroalumino
silicate glass particles & initator for light curing.
Liquid component consist of water & poly acrylic acid
with methacrylate & hydroxyl ethyl methacrylate
monomer.

19. 3.Metal modified GIC : Glass ionomer have been modified by addition of filler
particles ,to improve strength ,fracture toughness &
resistance to wear.
Silver alloy admix : This is made by mixing of spherical silver amalgam
alloy powder with type II GIC powder.
Cermet: Bonding of silver particles to glass ionomer particles by
fusion through high temperature sintering.

20. 4.Compomer : Compomer is a composite resin that uses an ionomer
glass which is the major component of glass ionomer
as the filler.
 Small quantity of dehydrated polyalkenoic acid
incorporated with filler particles,
 Setting reaction is light activated.
 Adhesive system used with compomer is based on acid
etch found with all composite resin.

21. 


Resistance to fracture is one of the main limitation
of using GIC. It is generally quite satisfactory for
one-surface lesion but a two surface lesion is
always at risk.
Resistance to abrasion and wear is little less than
composite resin.
They also remain susceptible to dehydration
through out lifespan, so that pt. with dry mouth
should not have restoration with GIC.

22. 

Text book of pedodontics, Shoba Tandon, 2nd
edition .
Dental material book, John J.M. 3rd edition.

23. THANK YOU