Abstract: There is provided a mixture which preferably is a colloidal suspension of finely divided particles of a rare-earth oxide such as cerium oxide in a liquid. The liquid may be all water but also may include other materials such as acetic acid, 1,3-butanediol, methanol. The mixture is used as a wetting and suspending agent for opaque and build-up dental porcelains to primarily overcome the problem of discoloration of the porcelains when used with metal substrates made of dental alloys containing silver, and also to make the porcelains easier to handle and to work with.