An aqueous dental glass ionomer composition comprising (a) a reactive particulate glass, and (b) a linear or branched polymer comprising acidic groups, which is reactive with the particulate glass in a cement reaction, whereby the linear or branched polymer comprising acidic groups has a polymer backbone and optionally pendant side chains, (c) optionally dispersed nanoparticles, and (d) optionally a low molecular compound, characterized in that the glass ionomer composition comprises -S x H groups, wherein x is an integer of from 1 to 6, which crosslink the particulate glass and/or the linear polycarboxylic acid and/or the optional dispersed nanoparticles and/or the optional low molecular compound.
