Glossary: Resin-Ionomer Cement
A combination of glass-ionomer and composite resin, these fillings are a mixture of glass, an organic acid, and resin polymer that harden when light cured. (The light activates a catalyst in the cement that causes it to cure in seconds.) The cost is similar to composite resin. It holds up better than glass ionomer, but not as well as composite resin, and is not recommended for biting surfaces of adult teeth. In general, resin-ionomer cements can achieve a better aesthetic result than conventional glass ionomers, but not as good as pure composites.