Calcium hydroxide is a white odorless powder with a molecular weight of 74.08. It has a high pH (approximately 12.5 to 12.8) and chemically classified as a strong base.Ca(OH)2 has many implications in endodontics and Its main actions come from the ionic dissociation of Ca2+ and OH- ions and their effect on vital tissues, generating the induction of hard tissue deposition and antibacterial activity.