Glass ionomer Cement.pptx

CONTENTS
 INTRODUCTION
HISTORY
CLASSIFICATIONS
COMPOSITION
MANIPULATION
SETTING REACTION
PROPERTIES
ADVANTAGES & DISADVANTAGES
INDICATIONS & CONTRAINDICATIONS
MODIFICATIONS
EEFECT OF WATER ON CEMENT
SURFACE CONDITIONING
RECENT ADAVANCES

INTRODUCTION
 Cement—Substance that hardens
from a viscous state to a solid state to
join two surfaces; for dental
applications, cements act as a base,
liner, filling material, or adhesive to
bind devices and prostheses to tooth
structures or to each other.
Glass ionomer cement (conventional
GIC)—A cement that hardens
following an acid-base reaction
between fluoroaluminosilicate glass
powder and an aqueous-based
polyacrylic acid solution.
 ADA specification number: 96
PHILIPS’ SCIENCE OF DENTAL MATERIALS (12TH EDITION)

HISTORY
First announced by Wilson and Kent in 1972.
The first GIC lacked workability and hardened slowly.
Eventually Kent et al, found a glass that was high in fluoride and
termed it as ASPA-I (aluminosilicates polyacrylates).
In 1972, Wilson and Crisp discovered that tartaric acid modified
the cement which was termed as ASPA-II and was used mainly for
Class III restorations.

CLASSIFICATIONS
• Type I - Luting
• Type II- Restorative
• Type III- Liner and base
According to Skinner
• Glass ionomer cement
• Resin modified GIC
• Polyacid modified GIC
According to Mc Lean,
Nicholson & Wilson
• Traditional or conventional
• Metal modified GIC
• Light cured GIC
• Hybrid
• Polyacid modifies resin composite
(compomer)
According to
Sturdevant

According to GJ
Mount
1.
Glass
ionomer
cements
Polyalkeonates
Polyphonates
Resin
modified
GIC
Polyacid
modifies
composite
resin
2.
Auto- cure
Dual-cure
Tri-cure
3.
Luting Restorative
Esthetic
Reinforced
Liner &
base

I • LUTING
II • RESTORATIVE
III • LINER/BASE
IV • PIT & FISSURE SEALANT
V • LUTING FOR ORTHODONTIC PURPOSE
VI • CORE BUILD UP MATERIAL
VII • FLUORIDE RELEASING
VIII • ART
IX • PAEDIATRIC GIC
According to clinical use

COMPOSITION
SILICA (SiO2) 29%
ALUMINA (Al2O3) 16.6%
ALUMINIUM FLUORIDE 5.3%
CALCIUM FLUORIDE 34.2%
SODIUM ALUMINIUM FLUORIDE 5%
ALUMINIUM PHOSPHATE 9.9%
RADIO-OPACIFIERS (lanthanum, barium, strontium)
POLYACRYLIC ACID 45%
WATER 50%
ITACONIC ACID, MALEIC ACID 5%
TARTARIC ACID
POWDER
LIQUID

SURFACE CONDITIONING
Treatment of surface was first introduced
by Mclean and Wilson in 1977 and they
termed it as surface conditioning.
Dentin conditioning prior to placement of
GIC is done primarily to remove the smear
layer.
Advantages:
•GIC is better able to wet the dentin surface
• Cement bonds to dentin and not to the
smear layer.
•It promotes ion exchange
•Increases surface energy.
Different acids used are:
10% citric acid, 3% hydrogen peroxide, Tannic
acid 25%,10% EDTA
A, Prepared dentin surface showing the presence of
the smear layer. B, After cleansing with polyacrylic
acid, the smear layer is removed

MANIPULATION
10sec
1st half
Gentle & rapid
rolling of powder
15sec
2nd half
Incorporation &
mixing
25-30sec
Mixing completed
Glossy wet
appearance

SETTING REACTION
Powder
and liquid
mixed
Surface
attacked with
H+ ion of acid
Release of
Ca2+ Al3+ Na+ F
Na+ ion
replaces H- ion
whereas
remaining form
NaF ,F ion thus
lie free within
the matrix
Replacement
of H+ on to
make calcium
and alumium
polysalts
The salt hydrate
to form a gel
matrix
Unreacted
portion of the
glass particles
are
surrounded by
silica

MECHANISM OF ADHESION
Attributed to two inter-related
phenomena, namely:
 Micromechanical interlocking caused
by glass-ionomers being self-etching
due to the polyacid component.
True chemical bonding: This involves
ionic bonds being formed between the
carboxylate groups on the polyacid
molecules and calcium ions in the tooth
surface.
Nicholson JW, Sidhu SK, Czarnecka B. Enhancing the Mechanical Properties of Glass-Ionomer Dental Cements: A Review
Interfacial ion-exchange layer formed between
tooth surface (above) and glass-ionomer cement
(below).

EFFECT OF WATER ON CEMENT
Incorporation of water with glass-ionomers is associated with
increase in the translucency of the cement.
Exposure of cement to saliva causes the surface to soften as the
vital cement forming ions are lost.
Loss of unbound water causes an unsightly chalky appearance as
microscopic cracks develop in the drying surface.
To prevent this, it is important to protect the cement by covering it
with an appropriate varnish or petroleum jelly.
Nicholson JW, Sidhu SK, Czarnecka B. Enhancing the Mechanical Properties of Glass-Ionomer Dental Cements: A Review

PROPERTIES
Flexural strength(Mpa) 25 Hardness (Knoop hardness
number)
48
Elastic modulus(Gpa) 3.5-9 Fracture toughness (Mpa/m) 0.88
Compressive strength(Mpa) 93-226 Fluoride release (mg) 14 days
30 days
1000
1300
Tensile strength(MPa) 3.9-8.3 Wear (volumetric change-cm3) 6.0
Shrinkage(%Vol) 3 pH 0.9 – 1.6
Film thickness(mm) 18-35 Solubility (wt%) 0.08-1.5
Setting time 1-9 Pulpal response Mild

Fluoride release
• The influence of fluoride action is
seen for at least 3 mm around the
glass ionomer restoration.
• Released for a sustained period of 18
months
• Thickly mixed cements release more
flouride than thinly mixed ones.
• Fluoride release is restricted by
sodium and to some extent by calcium
content.

Biocompatibility
 Pulp response to GIC is favorable.
 Freshly mixed cement has an acidic pH 0.9 – 1.6.
 Used to protect mechanical/ traumatic exposure of healthy pulp
Glass ionomer cement showed greater inflammatory response
than ZOE but less than Zinc phosphate cement.
Thermal Properties:
The thermal diffusivity value of GIC is close to that for dentin.
 The material has an adequate thermal insulating effect on the
pulp and helps to protect it from thermal trauma.

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.
Durability
Affected by:
• preparation of the cement
• protection of restoration
• Variable conditions of mouth
Failure rate depends on clinician’s skill than inherent quality of the
material.

WORKING TIME & SETTING TIME
 It sets rapidly in the mouth 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.
Applied Dental Materials (9th Edition) John F. McCabe

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.
DISADVANTAGES
•Brittle
•Soluble
•Abrasive
•Water sensitive during setting phase.
•Some products release less fluoride than
conventional GIC
•Not inherently radiopaque
•Less aesthetic than composite

INDICATIONS
Erosion/ abrasion
lesions
Restoration of
deciduous teeth
Sealing and filling of
occlusal pits and
fissures
Restoration of class III lesions,
preferably using a lingual
approach with labial plate intact
Occlusal approach
(tunnel preparation)
Core build-up
Other indications:
Repair of defective margins in
restorations
Minimal cavity preparations .

USE IN ENDODONTICS
Seal root canals
Perforation repair
Restore pulp chamber Repair vertical fracture
GIC was used because of :
• Its capacity to bond which enhances seal &
reinforce the tooth
• Its good biocompatibility, which would minimize
irritation to periradicular tissues
• Its F release, which imparts an anti microbial effect
to combat root canal infection

CONTRA-INDICATIONS
Class IV carious lesions Fractured incisors Class II carious lesions where
conventional
cavities are prepared.
Replacement of existing
amalgam restorations
Lesions involving large areas of
labial enamel
Lost cusp areas

Water Hardening Cements / Anhydrous Cements
To solve the problems associated with the instability of polyacrylic
acid, copolymer of acids were introduced which was stable in water.
In 1973 Wilson and Kent described the use of polyacrylic acid in
dry form blended with glass powder.
 Liquid consisted of water or an aqueous solution of tartaric acid.
This was termed as ASPA V by Prosser et al 1984.
Advantages:
•Developed very low viscosity in early mixing stages.
•Rapid set at minimal temperature.
•Easy manipulation.
• Excellent shelf life.

Products of this type include
•Chelon-Fil (3M ESPE)
•Nonencapsulated forms of Ketac-Cem (3M ESPE) and Ketac-Bond
(3M ESPE)

METAL MODIFIED GIC
MIRACLE MIX / SILVER ALLOY
ADMIXED GIC
Sced and Wilson in 1980
incorporated spherical silver
amalgam alloy into Type II GIC
powder in a ratio of 7:1.
Particle size of silver is 3 – 4μm

Properties of Metal Modified GIC
Higher strength.
Increased flexural strength.
Increased resistance to abrasion.
Increased fracture resistance.
Low thermal conductivity.
Coefficient of thermal expansion same as dentine.
Disadvantages
• Poor resistance to abrasion
• Resistant to burnishing
• Poor aesthetics

GLASS CERMET
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 8000C which is ground to fine powder particle size of
3.5 μm.
5%titanium dioxide is added to improve esthetics.
It has excellent handling characteristics.
Craig’s Restorative dental materials, Twelfth edition

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.
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

Composition
• Powder: Ion leachable fluoroaluminosilicate glass particles along
with camphorquinone as initiator.
• Liquid : water & polyacrylic acid modified with 2-hydoxyethyl
methacrylate (HEMA) monomers.
• The HEMA content is around 15-25% and water content is low to
accommodate the polymerizable ingredients.
Properties
•Esthetics: definite improvement in translucency as the monomer
brings the refractive index of the liquid close to that of the glass
particle.
• Fluoride release: 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 whereas adhesion to composites is
increased.
•Micro leakage: A higher degree is seen due to polymerization
shrinkage.
•Water sensitivity is considerably reduced.
•The biocompatibility is controversial and precautions such as
placing calcium hydroxide in deep preparations should be taken.
•The transient temperature rise during setting is also a concern.

CONDENSABLE / SELF HARDENING GIC
This is a high viscosity GIC launched in
early 1990’s.
These GICs contain smaller glass particle
sizes and use a higher P/L ratio, yielding
greater compressive strength.
They exhibit excellent packability for
better handling characteristics.
These glass ionomers are particularly
useful for ART.
ADVANTAGES
• Easy placement
• Non sticky
• Improved wear resistance
• Solubility in oral fluids is very low

CALCIUM ALUMINATE GIC
A hybrid product with a composition
between that of calcium aluminate and
GIC, designed for luting fixed prostheses.
 The main ingredients in the powder
are calcium aluminate, polyacrylic acid,
tartaric acid,strontium fluoro- alumino-
glass, and strontium fluoride.
 The calcium aluminate contributes to a
basic pH during curing, reduction in
microleakage, excellent biocompatibility,
and longterm stability and strength.

COMPOMER
Compomer is a polyacid-modified
composite made by incorporating
glass particles of GIC in water-free
polyacid liquid monomer with
appropriate initiator.
Compomer restorative materials
require a dentin-bonding agent prior
to their placement because they do
not contain water.

ADVANTAGES
• Superior working characteristics
• Ease of use
• Easily adapts to the tooth
• Good esthetics
Recently, a 2 component compomer is being marketed as a P: L
system or 2 paste system meant exclusively for luting.
 These are self adhesive due to the presence of water which starts
off the acid base reaction.

LOW VISCOCITY/ FLOWABLE GIC
It is mainly used as lining, pit and fissure sealing, endodontic
sealers, sealing of hypersensitive cervical areas, and it has
increased flow.

BIOACTIVE GLASS
Developed by Hench and colleagues in 1973, this material
considers the fact that on acid dissolution of glass, there is
formation of a layer rich in calcium and phosphate around the
glass, such a glass can form intimate bioactive bonds with
bone cells and get fully integrated with the bone.
It is used in retrograde filling material, for perforation repair,
augmentation of alveolar ridges in edentulous ridges, implant
cementation, and infra-bony pocket correction.

GIOMER
Developed by Shofu.
Giomer is a fluoride-releasing, resin-based dental adhesive
material.
It utilizes the hybridization of GIC and composite by using a unique
technology called the pre-reacted glass ionomer technology.
The fluoro aluminosilicate glass is reacted with polyalkenoic acid to
yield a stable phase of GIC which is then mixed with the resin.

HAINOMERS
These are newer bioactive materials developed by incorporating
hydroxyapatite within glass ionomer powder.
These are mainly being used as bone cements in oral maxillofacial
surgery.
After 1 and 7 days of setting, the nanohydroxyapatite/fluoroapatite
added cements exhibited higher compressive strength (177-
179MPa), higher tensile strength (19-20MPa) and higher flexural
strength (26-28MPa).
Cellulose, silks fiber and flax fiber have been employed in
designing biomaterials for medical applications.
Moshaverinia A, Ansari S, Moshaverinia M, Roohpour N, Darr JA, Rehman I. Effects of incorporation of hydroxyapatite and fluoroapatite nanobioceramics into
conventional glass ionomer cements

FIBER REINFORCED GIC
Incorporation of alumina fibres into the glass powder to improve upon its
flexural strength.
 This technology called the Polymeric Rigid Inorganic Matrix Material
(PRIMM) developed by Dr. Lars Ehrnsford
 It involves incorporation of a continuous network / scaffold of alumina
and SiO2 ceramic fibres.
ADVANTAGES
• Due to the ceramic fibers there is increased depth of cure as light
conduction and penetration is enhanced.
• Polymerization shrinkage is reduced
• Improved wear resistance
•Increase in flexural strength.
Ching HS, Luddin N, Kannan TP, Ab Rahman I, Abdul Ghani NRN. Modification of glass ionomer cements on their physical-mechanical and antimicrobial properties

ZIRCONIA CONTAINING GIC
Zirconia containing GIC – A potential substitute for miracle mix.
The tensile strength of zirconia containing GIC is significantly
greater than that of Miracle mix due to better bonding between the
particles and matrix.
Advantages
•Matchs the strength and durability of amalgam
•Sustained high fluoride release
•Easy mixing and handling characteristics
•Minimize chair time
•Enables ease of bulk placement
•Excellent resistance to abrasion and erosion

AMINO ACID CONTAINING GIC
An amino acid-containing GIC had better surface hardness
properties than commercial Fuji IX GIC.
This formulation of fast-set glass ionomer showed increased water
sorption without adversely affecting the amount of fluoride release.
Considering its biocompatibility, this material shows promise not
only as a dental restorative material but also as a bone cement with
low cytotoxicity.
Amino acid polyelectrolytes including proline are promising
additives to GICs polyacids.

CHLORHEXIDINE IMPREGNATED GIC
It provides a wide spectrum of activity against oral pathogen such
as Gram positive bacteria
For clinical use of GIC with CHX, the best option is the addition of
CHX at a concentration of 0.5%, since this combination increased the
antibacterial activity without changing the physical-mechanical
properties of the material.
However, the antimicrobial agents have extended the setting time
and weaken the compressive strength of GICs.
Other antimicrobials that can be used are triclosan, Chloroxylenol,
boric acid and thymol, benzalkonium chloride and chitosan.

GIC WITH ANTIBIOTICS
Incorporation of low quantity antibiotics into glass ionomer
cement for use with ART approach.
When conventional GIC was added with 1.5, 3.0 and 4.5% of
ciprofloxacin, metronidazole and minocycline it was effective for
inhibiting S. Mutans
A GIC with was chosen because of good preliminary laboratory
results and its possible use for the treatment of caries in primary
teeth.
The combination has shown biocompatibility and an antibacterial
effect in laboratory.

GLASS CARBOMER
This is a novel commercial material of the glass-ionomer type
which has an enhanced bioactivity .
It is manufactured by GCP Dental of the Netherlands.
The components are as follows:
• A glass powder that has been washed by strong acid
•A silicone oil comprising a polydimethylsiloxane, which contains
hydroxyl groups.
• A bioactive component, which also behaves as a secondary filler
The glass contains strontium, and also high amounts of silicon, as
well as a small amount of calcium and comparable amounts of
aluminium, phosphorus and fluoride.
Nicholson JW, Sidhu SK, Czarnecka B. Enhancing the Mechanical Properties of Glass-Ionomer Dental Cements: A Review.

NANOTECHNOLOGY IN GIC
Nanotechnology involves the use of systems, modifications,
or materials that have the size in the range of 1–100nm.
Recent studies have suggested that incorporation of nano-
sized particles or “nanoclusters” can improve the mechanical
properties of dental restorative materials such as resin
composites.

1. POWDER-MODIFIED NANO GIC
 Described for the first time by De Caluwé et al., it involves
doping conventional GICs with nano-sized glass particles,
which can decrease the setting time and enhance the
compression strength and elastic modulus.
 The main advantages of decreasing setting times of direct
restorative materials are enhanced ease of handling and
manipulation.

1. POWDER-MODIFIED NANO GIC
a. Modification using nano-apatite: Addition of nano-apatite or
nano-fluoroapatite to the powder component of
conventional GIC has a positive impact on the compressive,
tensile, and flexural strengths of the set cement after being
stored in distilled water for 7 days.
b. Modification with nano-sized hydroxyapatite, calcium
fluoride, and titanium dioxide particles: It has been recently
reported by Gu et al. that the combined incorporation of
HAp and zirconia (HAp/ZrO2) at concentrations of 4%
volume to the GIC powder can improve the mechanical
properties of the set GIC.

2. NANO-FILLED RESIN-MODIFIED GIC
 Resin-modified GICs also have a polymer resin component,
which usually sets by a self-activated (chemically cured) or
light-activated polymerization reaction.
 To develop the mechanical properties of a resin composite
with the anticaries potential of GICs, these were developed.
 However, compared to composites, resin-modified GICs
have reduced mechanical properties, including brittleness
and inferior strength along with aesthetics.
 To overcome these drawbacks, there have been attempts to
incorporate nano-sized fillers and bioceramic particles to
RMGICs.

Properties of nano-RMGICs
a.Bonding of nano-RMGIC with tooth structure: More ionic
bonding with tooth rather than micromechanical retention,
much akin to conventional GICs.
b.Mechanical and physical properties of nano-RMGICs: Poor
flexural strength and fatigue limit in commercially available
nano-RMGICs. Perform the worst when mechanically tested on
acid challenge. Acidic environment may jeopardize the long-
term survival rate of nano-RMGICs.
c.Surface mechanical properties of RMGICs: The aesthetic
properties of dental resin composite materials have been
radically improved.
d.Fluoride release from nano-ionomers: Slightly increased
fluoride release from nano-RMGICs at a pH of 4.

CONCLUSION
Among all the dental restorative materials, GICs are found to be
the most cariostatic and has antimicrobial properties due to release
of fluoride, which helps in reducing demineralization, enhance
remineralization and inhibit microbial growth.
However, up to date none of the restorative material available can
be regarded as ideal and perfect.

REFERENCES
 Philips science of dental materials 12th edition
Applied Dental Materials (9th Edition) John F. McCabe
 Craig’s Restorative dental materials, Twelfth edition
Nicholson JW, Sidhu SK, Czarnecka B. Enhancing the Mechanical
Properties of Glass-Ionomer Dental Cements: A Review. Materials (Basel).
2020;13(11):2510. Published 2020 May 31.
Ching HS, Luddin N, Kannan TP, Ab Rahman I, Abdul Ghani NRN.
Modification of glass ionomer cements on their physical-mechanical and
antimicrobial properties. J Esthet Restor Dent. 2018;30(6):557-571.
Moshaverinia A, Ansari S, Moshaverinia M, Roohpour N, Darr JA, Rehman
I. Effects of incorporation of hydroxyapatite and fluoroapatite
nanobioceramics into conventional glass ionomer cements (GIC). Acta
Biomater. 2008;4(2):432-440. doi:10.1016/j.actbio.2007.07.011

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