Proper diagnosis, thorough debridement, shaping and three-dimensional filling of the root canal system is essential for a successful root canal therapy. Aiming for this ideal should be the goal of every endodontic professional. research results have revealed the inadequacy of the traditional method of canal debridement such as hand instrumentation. The addition of ultrasonics has been the single technological breakthrough that has vast clinical application spanning from Non-surgical treatment and retreatment to surgical Endodontics. This book provides an insight into the use of ultrasound in Endodontics.