[The formulation of glass ionomer cements and the amount of fluoride].

The glass-ionomer cements (GIC) were developed in the late sixties. The set cement is the result of an acid-base reaction between an ion-leachable glass (the base) and a poly (alkenoic acid). Through the years, the number of applications of these GIC has increased steadily. The evolution has to be referred to the fact that the composition of both acid and base can be changed considerably. This has resulted in the marketing of GIC with different physical and chemical formulations. Furthermore resin-modified GIC were introduced in the late eighties. One of the major GIC advantages remains the fluoride release. The fluoride in GIC is a component of the material itself and is not added afterwards. Beneficial for the GIC in this respect is that the released fluoride is not of structural importance in the set cement. Furthermore the fluoride release does not result on itself in a reduction of physical properties or an increase in porosity.