The present invention relates to an aqueous dental glass ionomer composition comprising
(A) a reactive particulate glass,
(B) a water-soluble, polymerizable polymer comprising acidic groups, which is reactive with the particulate glass in a cement reaction, whereby the polymerizable polymer has a polymer backbone and pendant groups having one or more polymerizable carbon-carbon double bonds, wherein the polymerizable polymer is obtainable by a process comprising
a) a step of polymerizing a mixture comprising
(i) a first polymerizable monomer comprising at least one optionally protected carboxylic acid group and a first polymerizable organic moiety, and optionally
(ii) a second copolymerizable monomer comprising one or more optionally protected primary and/or secondary hydroxyl and/or amino group(s) and a second polymerizable organic moiety, for obtaining an water-soluble polymer;

b) a step of coupling to the water-soluble polymer a compound having a polymerizable moiety and a functional group reactive with an optionally protected carboxylic acid group of repeating units derived from the first polymerizable monomer or an optionally protected hydroxyl and/or amino group of repeating units derived from the second copolymerizable monomer in the water-soluble polymer obtained in step a), wherein the optionally protected carboxylic acid group and the optionally protected hydroxyl and/or amine group are deprotected, so that polymerizable pendant groups are linked to the backbone by ester groups, urethane groups and/or amide groups,
and, optionally, a step of deprotecting the protected carboxylic acid group after step a) or step b), for obtaining a polymerizable polymer;
(C) a hydrolysis-stable, water-soluble monomer having a single polymerizable double bond and optionally a carboxylic acid group or hydroxyl group; and
(D) a polymerization initiator system.