Endodontic treatment aiming to cure and prevent apical periodontitis to retain tooth as long as possible, functioning without symptoms. In order to achieve this, we must performed root canal preparation to reduce bacteria to the level that necessary, this mean we shape and clean the root canal system to its terminus.
But we need to bear in mind that in order to achieve long term predictability we also need to save tooth structure specially the PCD area in order tooth to withstand occlusal force for period of time