Z

zinc n. A metallic element which used to be added to *amalgam alloy during manufacture to act as a scavenger for oxygen; however, its presence can cause the amalgam to expand in the presence of moisture, which can lead to tooth fracture. The addition of zinc is now avoided by manufacturing the alloy powder in an oxygen-free inert atmosphere.

zinc chloride n. A compound used as an *astringent to control localized bleeding. Absorbent cord may be impregnated with zinc chloride for gingival retraction. It is added to toothpaste as a *desensitizing agent and for its bacteriostatic properties.

zinc oxide cement See CEMENT.

zinc oxide eugenol (ZOE) impression paste n. 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