
Calcium Hydroxide is a material which has been used for a variety of purposes since its introduction in dentistry in the early part of the twentieth century. In its pure form, the material has high pH and its dental use is based chiefly on its ability to stimulate mineralization and its antibacterial properties. A range of products have been formulated with different therapeutic actions, the effects of which are partially dependent upon the tissue to which they are applied. The material is reviewed under the following headings:- history, it is physio-chemical properties, mechanism of action, role and uses in endodontics, combination with other agents, methods of placement and removal in root canals and biocompatibility.