Glass Ionomer Based Sealants

Glass ionomer cement sealants (GICs) are hydrophilic (moisture tolerant)and have fluoride releasing properties. The fluoride is released from the sealant after polymerization, and continues to slowly release over time for up to 8 years . GICs auto-cure as the result of an acid-base chemical reaction between a liquid, commonly polyacrylic acid, and a powder comprised of minerals including silicon oxide, aluminum oxide, and calcium fluoride. Low viscosity glass ionomer cement (LVGIC) wears more rapidly over time in comparison to RBSs or high viscosity glass ionomer cement (HVGIC). However, loss of complete retention of GICs is not associated with the risk of developing caries because small particles remain in the bottoms of fissures that act as a fluoride reservoir enhancing nearby enamel remineralization.⁶ The thinner consistency of LVGICs flows nicely into pits and fissures, thicker HVGICs requires more adaptation into the anatomy of the tooth. Both can be adapted to the tooth with a damp cotton swab or finger press. HVGIC is durable and wear resistant, making it a good material choice to improve retention, if desired. GICs chemically bond to enamel and dentin without the need for an intermediate agent, such as bonding agent. The use of a surface conditioner, typically 10 – 20% polyacrylic acid, removes the smear layer and is recommended to improve chelation and enhance the chemical bond between the GICs and the tooth surface.¹⁰ Resin-modified glass ionomer (RMGI) will not remineralize as well as a pure GICs, but its photopolymerizable ionomers allow it to be light-cured.³ Resin-modified glass ionomers (RMGI) undergo more wear than pure resin sealants. However, there is evidence of residual RMGI retention in the deepest portions of the pit and fissure, with sustained fluoride release. Recent studies show little difference in overall caries prevention, however, more conclusive research is needed.^3,11