The most important aim of endodontics is the preservation of natural teeth. Accurate working length determination is a crucial part of successful endodontic treatment. It is said that "Apex is the essence of endodontics." There are certain important features at the apex of the tooth with which one needs to be familiar if an accurate working length is to be determined. If calculated within correct limits, working length will play an important role in determining the success of the treatment, and conversely, if calculated incorrectly may doom the treatment to failure. Therefore it can be seen...