The application relates to a kit of parts for preparing a glass ionomer composition for dental use, the kit comprising a Paste A and a Paste B, Paste A comprising water, acid-reactive inorganic filler C, non acid-reactive filler A, Paste B comprising water, polyacid, complexing agent, non acid-reactive filler B, the mean particle size of non acid-reactive filler B being larger than the mean particle size of non acid-reactive filler A, the water content of the composition obtained when mixing Paste A and Paste B being below 20 wt.-%. The application also relates to a device for storing such a kit of parts and the use of the kit of parts and/or the device for preparing a dental cement, dental filling material, dental core build up material or dental root channel filling material.