GIC was introduced in 1972 by Wilson and Kent.It was developed in attempt to combine the favorable properties of silicate cement and polycarboxylate cement.The first introduced GIC was opaque, limited shade selections, mixing and handling problems and technic sensitivity.
Glass: silicate glass powder
Ionomer: ionomeric acid
Other name: Polyalkenoate cement
Their are basically three types of GICs-
Type 1- for luting application
Type 2- for restorative material
Type 3- for liners/ base
Composition
Powder- acid-soluble calcium fluoroalmine silicate glass.
Acid is in the form of copolymer of itaconic maleic acid or tricarboxylic acid.Tartaric acid is also present in the liquid.It improves handling characteristic and increase working time , decreases setting time.
Water soluble GIC / Anhydrous GIC
To extend working time,Shorter setting time
One– freeze dried powder and glass powder bottle
When powder with liquid are mix to form paste, surface of glass particle is attached by acid.Calcium,Aluminium,fluoride ions are leached into the aqueous medium.Poly acrylic acid chains are cross linked by calcium ions and form a solid mass.
Within next 24 hours a new phase forms in which aluminium ions become bound in the cement mixture.This leads to more rigid set cement.
The solid particle represent unreacted glass particle surrounded by gel that form when aluminium ions and calcium ions are leached from glass as a result of attack of poly acrylic acid.The calcium ions and aluminium ions form polysalts with carboxylate ion group of polyacrylic acid so forms a cross linked structure.
Post operative procedure– Coat of varnish / resin for protection
There are two types of metal modified GIC,
•Glass powder fused to Ag particles
It involves fusing glass powder to Ag particle by high temperature rintering of mixture of two powder.It is common called as cermet.
Metal reinforced GIC
General properties-
Both metal reinforced systems release fluoride initially but magnitude decreases over time.Less fluoride is released from cermet.
Mechanical properties-
-Strength: Of either type of metal modified cermet is not greatly improved over that of conventional GICs.
-Fracture toughness: extremely low as compared to composite resin and amalgam.
–Wear resistance: similar to other materials
–Anti cariogenic properties: Both have anticariogenic properties due to fluoride release. Cermet release less fluoride since glass particle is metal coated.
–Esthetic: Gray in color. Unsuitable for anterior teeth.
Contributor- Dr. Somya Deep Kaur
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