Glass ionomer is one of the Oppressed in Restorative materials.
Compared with Composite, it has a lot of Advantages:-
-Biocompatible
-No Post-operative sensitivity, due to:-
- containing weak acid which is Polyacrylic acid
- Don't require Acid etch
- The large molecular size of Polyacrylic acid prevents pass or penetration of Dentinal Tubules (DT).
- don't generate heat during the setting phase.
- Chemical Adhesion to Tooth ( Calcium bind with enamel & Collagen Fibers with dentin ).
-Fluoride Release ++ ( Anti Cariogenic ).
-has Less Shrinkage than Composite during the setting phase by 7 times, leading to less stress on margins integrity.
But
with all its Advantages, still have a lot of Disadvantage which prevent to use as a final Restoration
Low Fracture toughness
limiting applications in high load-bearing areas ( for example Class II ).
Can't be finished & polished at the same visit they are placed ( only after the first 24h )
vulnerable to erosion especially acid erosion
Low flexural strength & wear resistance.
Poor Esthetic
all of that makes it almost impossible to use it as a final restoration.
a lot of Companies are looking to improve the Esthetic and physical properties of Glass ionomer restoration and cement to be Close as much as possible to Composite
( and on top of these companies is GC Fuji,© GC America Inc.)
Type of Glass ionomer:-
Type 1 Luting Cement ( for cementation of crown & bridges ).
Type 2 Restoration Cement ( restoration ).
Type 2 ( I ) Restorative Esthetic
Type 2 ( II ) Restorative Reinforced
Type 3 Liner / Base ( Base under restoration like Amalgam & Composite ).
Type 4 Pits & Fissure sealant.
Type 5 Orthodontic Cement.
Type 6 Core Build-up Material.
Type 7 High Fluoride releasing command set
Type 8 Atraumatic restoration treatment
Type 9 Pediatric GIC.
