Glass ionomer cement report



Glass ionomer cement is a tooth coloured
material, introduced by Wilson & Kent in
1972.



-a.k.a glass polyalkenoate
Silicate Glass
Powder

Polyacrylic acid

GIC

Type I. For luting
Type II. For restoration
Type II.1 Restorative esthetic
Type II.2 Restorative reinforced
Type III. For liner & bases
Type IV. Fissure & sealent
Type V. As Orthodontic cement
Type VI. For core build up

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:
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



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.

 Calcium

poly salts are formed first, then followed
by aluminum poly salts which cross link with poly
anion chain.

 Set

cement consist of unreacted powder particle
surrounded by silica gel in amorphous matrix of
hydrated calcium & aluminum poly salts.

 Calcium

poly salts are responsible for initial set.

 Aluminum

poly salts form the dominant phase.

 Water

plays an important role in structure of
cement.
 After hardening, fresh cement is extremely
prone to the cracking & crazing, due to drying
of loosely bound water .
 Hence these cements must be protected by
application of varnish.



Type I

4 - 5 minutes



Type II 7 minutes



Handling characteristics:
 Previous versions of GIC had problems with

inappropriate working and setting time.
Tartaric acid inclusion resulted in:
▪ Tartaric acid reacting with calcium as it was
released which extends working time to
reasonable values
▪ Enhances rate of formation of aluminum
polyacrylate crosslinks which speeds up setting.

Solubility and disintegration:
 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.
 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.



Esthetics:
 GIC is tooth coloured material & available in

different shades.
 Inferior to composites.
 They lack translucency & rough surface
texture.
 Potential for discolouration & staining.

 Biocompatibility:

 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



Anticariogenic effect:
 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.



Strength:
 Compressive strength - 150 mpa
 Tensile strength - 6.6 mpa.

 Hardness - 49 KHN.

ADVANTAGES:
♣
♣
♣
♣
♣

Inherent adhesion to the
tooth surface.
Good marginal seal.
Anticariogenic property.
Biocompatibilty
Minimal cavity
preparation required.

DISADVANTAGES:
Low fracture resistance.
Low wear resistance.
Water sensitive during
setting phase .
♦ Less esthetic compared
to composite.
♦
♦
♦

1.
2.
3.
4.
5.
6.
7.
8.

Anterior esthetic restoration material for class
III & V restorations.
For luting.
For core build up.
For eroded area .
For atraumatic restorative treatment.
As an orthodontic bracket adhesive.
As restoration for deciduous teeth.
Used in lamination/ Sandwich technique.



For luting:
 Advantages:
▪ Fluoride release
▪ Low film thickness
▪ Kind to pulp
▪ Bond to tooth structure
 Their use decreased after hybrid ionomers

and resin cements were introduced since
they are stronger



As restorative material:
 used in non-stress bearing areas:
▪ Root caries
▪ Occlusal lesions in primary teeth
▪ Temporary restorations
▪ Cervical cavities (abrasion and erosion lesions)
▪ Anterior class III when color matching is not an
issue



As liners and bases:
 used to protect the pulp from:
▪ Temperature changes
▪ Chemicals from other restorative materials
▪ Acid etchants
 Liners have lower powder: liquid ratio and

weak.
 GIC bases are used to rebuild missing tooth
structure, stronger than liners and have a
higher powder: liquid ratio



As pits and fissure sealants:
 The use of GICs as sealants have been suggested

due to:
▪ Fluoride release.
▪ Adhesion to moist tooth structure

 Disadvantages:
▪ Inability to fully penetrate fissures
▪ Brittleness
▪ Low wear resistance



Core build up materials:
 cermet GICs are usually used for this

purpose. They are used:
▪ In locations were esthetics are not important
▪ To replace missing tooth structure where the
permanent restoration is crown.

 Devolped

by Mclean,
 To combine the beneficial properties of GIC &
composite.





An effective technique for both anterior and
posterior resin based restorations.
For pulpal protection from the acid-etch
technique.
And as a mechanism for sealing the cavity in the
absence of good dentin adhesion available with
the materials of the time.



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
orthophosphoric acid for 15 seconds. This will
improve micromechanical bond to composite resin.
 Apply a thin layer of low viscosity enamel bonding
agent & finally place the composite resin over GIC &
light cure it.



Advantages:
 Polymerisation shrinkage is less,due to reduced bulk

of composite.
 Favorable pulpal response.
 Chemical bond to the tooth and composite
increasing retention form.
 Provides better seal when used at nonenamel
margins.



Advantages:
 Anticariogenic property
 Potential for recurrent caries low.

 Decreased microleakage and gap formation.
 Better strength, finishing, esthetics of overlying

composite resin.



Advantages for the flowable composite:
(as a liner under a composite)
 Acts as a shock absorber, distributing stresses applied

to the more rigid composite.
 Reduce some of the negative effects of
polymerization shrinkage.

TWO TECHNIQUES:
1. Closed Technique
- The traditional technique.
-Involves the placement of GIC at the base of the
proximal box so as it falls just short of the external
cavo surface. After setting, the GIC is etched with
phosphoric acid and dentin bonding agent is
applied before placing composite resin into the
proximal box and occlusal surface.


2. Open Technique
- Involves the placement of GIC into the base of a
proximal cavity and filling the preparation with glass
ionomer upto the DEJ. The last portion of the
restoration is placed with composite resin to provide
wear resistance and esthetics on the occlusal surface.
- For clinical situations where a portion of the
restoration would have a dentin only margin (as in a
deep class II or a class V on a root surface).

- Advantage of Open Technique:
a. The large area of GIC available for buffering
any changes in acidic pH.
-Disadvantage of Open Technique:
b. Over time the GIC succumbs to acid breakdown
over the surface resulting in food packing and
recurrent caries within glass ionomer.



Factors necessary for successful tooth
restoration:
 Removal of infected dentin and enamel completely
 Treating the enamel and dentin appropriately with

bonding materials.
 Manipulating properly the to-be-bonded restorative
material.
 Contouring the restoration to provide proper form
and function.



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.

1. Water settable glass ionomer cement:
 Liquid is delivered in a freeze dried form, which
is incorporated into the powder.
 Liquid used is clean water.



Advantages:
 low viscosity in the early mixing stages
 improved shelf

 Improved strength

2. Resin modified glass ionomer cement:
 Resin composite + conventional 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.



Advantages:
 greater working time
 command set on application of visible light

 good adaptation and adhesion
 acceptable fluoride release
 aesthetics similar to those of composites
 superior strength characteristics



Disadvantages:
 setting shrinkage
 limited depth of cure especially with more opaque

lining cements.

3. Metal modified glass ionomer cement:
 Glass ionomer have been modified by addition of
filler particles to improve strength , fracture
toughness & resistance to wear.
Silver alloy mix / miracle mix: This is made by mixing of spherical silver amalgam
alloy powder with glass ionomer powder.
Cermet:
 Bonding of silver particles to glass ionomer
particles by fusion through high temperature
sintering.



Cermets
 Grey in color
 Greater value of compressive strength and fatigue

limit than conventional glass ionomers
 Flexural strength and resistance to abrasive wear
appear no better than values recorded for
conventional GIC
 Rapid setting  improved erosion resistance
 Lower Fl release

4. Giomer
 It is basically a modified Glass Ionomer.
 It is a hybrid of Glass Ionomer and Composite.
 The GIOMER concept is based on the novel
PRG (Pre-Reacted Glass Ionomer)
technology, where special PRG fillers are
included in the resin matrix which differs it
from Compomer making it possess both
properties of Composite and Glass Ionomer.



PRG technology is used in production of two
types of fillers.
 S-PRG(Surface Pre-reacted GI) eg. Beautiful by

Shofu
 F-PRG(Full Pre-reacted GI) eg. Reactimer by shofu



Properties









Fluoride release
Esthetics (shade conformity)
Ease in Polishing
Strength (resistance to wear)
High radiopacity
Anti-Plaque Effect
Biocompatibility
Long term clinical stability



Composition
 Bisphenol A Glycidyl Dimethacrylate
 TEGDMA

 Inorganic Glass Filler
 Aluminuoxide
 Silica
 PRG filler
 DL-camphorquinone



Indications
 Diastema Closure
 Discoloration
 Non-Carious Defect(attrition/ abrasion/ surface





defects
Carious Defect
Fracture
Malformation
Faulty and Old Restoration



Compomer
 These are recently introduced products marketed

as a new class of dental materials.
 These materials are said to provide the combined
benefits of composites (the “comp” in their name)
and glass ionomers (“omer”).



These materials have two main constituents:
 dimethacrylate monomer(s) with two carboxylic

groups present in their structure and
 filler that is similar to the ion-leachable glass
present in GICs.

 The ratio of carboxylic groups to backbone carbon

atoms is approximately 1:8.
 There is no water in the composition of these
materials, and the ion-leachable glass is partially
silanized to ensure some bonding with the matrix.
These materials set via a free radical
polymerization reaction, do not have the ability to
bond to hard tooth tissues, and have significantly
lower levels of fluoride release than GICs.

 Although low, the level of fluoride release has

been reported to last at least 300 days.
 They do not set via an acid-base reaction and do
not bond to hard-tooth tissues, they cannot and
should not be classified with GICs.

Properties











Fluoride release,
Radiopaque,
Quick cure time and
Good handling characteristics (no slumping, easy to
shape/polish, no sticking)
Can be light-cure or self-cure
Packaging can be unit dose (capsule) or multi-dose
(syringe)
Curing time: 10-20 secs (depending on brand)
Esthetics



Indications
 Deciduous teeth
 Cervical defects

 Disadvantages
 Lower flexural modulus of elasticity,
 Compressive strength,

 Flexural strength,
 Fracture toughness and hardness,
 Higher wear rates



Davidson, C. (2009) Advances in glass-ionomer cements. Journal of
Minimum Intervention Dentistry.



Forsten L. Fluoride release of glass ionomers. J Esthet Dent 1994; 6:21622.



Forsten L. Resin-modified glass ionomer cements: fluoride release and
uptake. Acta Odontol Scand 1995; 53:222-5.



McCabe, J. and Walls, A. Applied Dental Materials 9th edition Chap.24
pp.245-256



Millar BJ, Abiden F, Nicholson JW. In vitro caries inhibition by polyacidmodified composite resins (‘compomers’). J Dent 1998; 26:133-6.



Nagaraja Upadhya P and Kishore G. (2005) Glass Ionomer Cement – The
Different Generations. Trends Biomater. Artif. Organs, Vol 18 (2)

Glass ionomer cement report

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