A non-elastic irreversible impression material used for relining partial or complete dentures. It is supplied as a base paste containing zinc oxide, olive oil, linseed oil, zinc acetate, and a trace of water and a catalyst paste containing eugenol, filler, accelerator, gum rosin, and oils. When the two pastes are mixed together, zinc eugenolate is formed. The trace of water initiates the reaction and the zinc acetate speeds up the setting process. Eugenol may be substituted with other compounds such as lauric acid to eliminate the odour and taste of eugenol, or for patients allergic to eugenol. The mixed material adheres well to denture bases, has adequate rigidity to prevent distortion of the impression borders, can be added to, has good accuracy of surface detail, and has good dimensional stability. It is, however, difficult to remove from instruments, and because of its adherence to dry skin the lips benefit from protection with petroleum jelly.