The present invention relates to a composition for attaching a dental facing on a dental support structure comprising water, a glass and/or glass ceramic material, a rheological modifier with a molecular weight above about 500,000. The invention also relates to a process comprising the steps: providing a dental facing precursor and a dental support structure, both having an upper and a lower surface, attaching the dental facing precursor with its lower surface to the upper surface of the dental support structure, comprising the step of placing a mating composition between the lower surface of the dental facing precursor and the upper surface of the dental support structure and to the use of the inventive composition for producing dental restorations.