Glass Ionomer Types and Modifications

Glass Ionomer Types and Modifications

1. Glass Ionomer Types and
Modifications
Presented By: Stephanie Chahrouk

2. INTRODUCTION
 “Glass ionomer cement is a tooth coloured material, introduced by
Wilson &Kent in 1972.”
 “Material was based on reaction between silicate glass powder
&polyacrylicacid.”
 “They bond chemically to tooth structure & release fluoride for
relatively long period. “

Classifications
“Traditional Glass Ionomer
o Type I: Luting cement
o Type II: Restorative Cements
o Type III: Liners and bases”
“Metal Modified Glass Ionomere
o Miracle Mix
o Cement cement“
Light cure Glass Ionomer
“Hybrid or Resin Modified Glass Ionomere
o Composite Resin in which fillers substituted with glass ionomer
particles
o Pre-cured glass blended into composite “

3. Classifications
Type IFor luting
Type IIFor restoration
o Restorative esthetic
o Restorative reinforced
Type III for liner & bases
Type IV Fissure&sealant
Type V Orthodontic cement
Type VI for core build up

PROPERTIES
Adhesion:
“Glass ionomer cement bonds chemically to the
tooth structure.”
“Bonding is due to reaction occurring between
carboxyl group of poly acid & calcium of hydroxyl
apatite.”
“Bonding with enamel is higher than that of dentin,
due to greater inorganic content”.
o “Primarily chemical (calcium – carboxyl groups) “
o “Micromechanical”
o “Bond to enamel better than bond to dentin “
o Barriers to adhesion
 smear layer not removed
 contamination (blood, saliva, too much water)
 setting reaction too far advanced before application (cement
must have a glossy surface when applying to tooth.)

4. Esthetics:
“GIC is tooth coloured
material & available in
differentshades.
Inferior to composites.
They lack translucency &
rough surface texture
Potential for discoloration&
staining”



MODIFICATIONS
“Modifications in the powder:
o Dried Poly Acrylic Acid (Anhydrous GIC)
o Silver-Tin Alloy (Miracle Mix)
o Silver-Palladium/ Titanium (Cermet cement)
o BisGMA, TEGDMA, HEMA (Light cure/Dual cure GIC)
Modifications in the liquid:
o Only water and tartaric
acid (Anhydrous GIC)
o HEMA (Light cure
components)”

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


2-Resin modified glass ionomer cement :
c. “Powder component consist of ion leachable fluroalumino silicate
glass particles &initator for light curing.
d. Liquid component consist of water & poly acrylic acid with
methacrylate & hydroxyl ethyl methacrylate monomer.”

3-Resin Modified Glass Ionomer
Also known as:
o Visible Light Cure Glass Ionomers (VLC)
o Hybrid Glass Ionomers
Composition
o Liquid
 Polyacrylic acid copolymer
 Tartaric acid
 Methacrylate groups (HEMA)
 Photoinitiator

6. o Powder
 Same powder as chemical cure glass ionomer
 Photosensitizer
o Setting Reaction
 Polymerization of resin + normal glass ionomer acid-base
reaction
 If not supplied in two components, not a glass ionomer

Requirements to be a Resin Modified Glass Ionomer Cement
I. Acid-base reaction critical to setting
II. Have a pH change & formation of carboxylate salt
III. Material must contain fluoroaluminosilicate glass, a polymeric
carboxylic acid and water•
Comparison to Conventional Glass Ionomer
I. Generally improved physical properties
II. Improved shades and translucency
III. Water sensitivity reduced
IV. Can be finished almost immediately
V. Slightly less fluoride release
VI. Fluoride can still be recharged
VII. Slight increase in thermal expansion
VIII. Can be dual or tri-cure
Precautions
I. Must be light cured to achieve good bond
II. Fill in increments of 2 mm’s or less
III. Bond to dentin highly dependent on surface conditioning

7. 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 admix / miracle mix:-
o This is made by mixing of spherical silver amalgam
alloy powder with glass ionomer powder
Cerment:
o Bonding of silver particles to glass ionomer particles by fusion
through high temperature sintering.
A. Strength Silver alloy admix (silver amalgam alloy
particles mixed with glass particles)
B. Cermet (glass sintered with silver
o Physical Properties compared to conventional glass ionomer cement
a. Strength>> Same
b. Fracture Toughness>> Same
c. Wear Resistance>> Increased slightly
d. Fluoride release >> reduced with Cermet, same or
slightly increased with admix
4.Compomer :- ( POLYACID MODIFIED COMPOSITE
RESINS )
1. “Compomer is a composite resin that uses an ionomer
glass which is the major component of glass ionomer
as the filler
2. Small quantity of dehydrated polyalkenoic acid
incorporated with filler particles,
3. Setting reaction is light activated.
4. Adhesive system used with compomer is based on
acid etch found with all composite resin.

8.  Combination of composites (comp) and glass ionomers (omers).
 Compomer is a one-paste material consisting of fillers and a matrix that is
similar to that of composite resin.
 contains fluoroaluminosilicate glass powder as filler to release fluoride
 Contains dimethacrylate monomer and carboxylic groups along with ion
leachable glass.
 There is no water in the composition Glass particles are partially silanated
to ensure some bonding with the matrix.
 contains strontium or some other metal to make the material radiopaque”

5.Giomers
 “A recent addition to the continuum of hybrid materials
is a class of anhydrous resin-based restoratives that
utilizes prereacted glass ionomer technology (PRG)
 E.g. Beautiful (Shofu); Reactmer paste (Shofu).
 Known as “giomers” in Japanese market, these
materials incorporate fillers that areproduced from the
complete or partial reaction of ion-leachable glasses
withpolyalkenoic acid.
 giomers may contiain either fully prereacted (F-PRG) or surface prereacted
(S-PRG)fillers as part of the total filler composition
 Unlike compomers, immediate fluoride release may occur from the PRG
fillerswithout the need for in-situ acid-base reaction via water sorption.”

9. Reference:Sturdevant Art and Science of Operative Dentistry