Calcium phosphate cements (CPCs) are under study for dental applications such as root canal filling or sealing and pulp capping. Upon setting they are converted principally to hydroxyapatite, the mineral constituent of bone. The presence of a small amount of fluoride or hydroxyapatite in the cement mixture hastens the setting time. Nevertheless, the CPCs set much more slowly than plaster of Paris (calcium sulfate hemihydrate) when moistened with water or dilute phosphoric acid.Hydroxylapatite (HA) is hydroxyapatite which has been processed either by sintering or firing into a dense ceramic or made into porous particles. Plaster has been found very useful as a binder to prevent the scatter of HA particles implanted for jawbone reconstruction. The composite HA/plaster implants can be tailored to fit the site during surgery or preformed and sterilized prior to surgery.