A dental appliance comprising a hard, shaped body having at least one portion comprising a polymerized blend of: From 0% to about 50% of an uncrosslinked polymer capable of dissolving in component; From about 0% to 50% of a monofunctional polymerizable monomer; From about 0% to 40% of a highly crosslinked polymer in the form of ground particles having average diameters up to about 500 microns; From about 0% to 50% of a crosslinked polymer in the form of discrete particles having average diameters up to about 500 microns and being easily swellable by said monomer; and From about 5% to about 35% of a di- or polyfunctional crosslinking agent.