An experimental material, mineral trioxide aggregate (MTA)was developed in loma linda university.it is a mixture of portland cement and bismuth oxide mainly.MTA has numerous applications in filed of endodontics and restorative dentistry such as perforation repai,root end filling material,pulp capping agent n obturating material,apexification.Several in vitro and in vivo studies have shown that MTA prevents microleakage, is biocompatible, and promotes regeneration of the original tissues when it is placed in contact with the dental pulp or periradicular tissues.