Dental cements are hard, brittle materials formed by mixing powder and liquid together. They are either resin cements or acid-base cements. In the latter the powder is a basic metal oxide or silicate and the liquid is acidic. An acid base reaction occurs with the formation of a metal salt which acts as the cementing matrix.
Dental cements are used for a variety of dental and orthodontic applications, including use as luting agents, pulp-protecting agents or cavity-lining material. Furthermore, they are used to form an insulating layer under metallic or ceramic restorations, and protect the pulp from injury. This helps in sealing or fixing and casting inlays, onlays or any such substance to both dentin and enamel. Dental cements which contain an acid component may have an intense sour taste.