Root canals are done to protect a tooth, the calcified tissues of the tooth. This helps in maintaining the jaw integrity. If the entire tooth is extracted, the space in between the adjacent teeth can lead to shifting around of those teeth if a bridge or implant placement is not done rightly there. So, a root canal treatment is advised for the protection of the tooth during an infection The thickness of the calcified structure would be considered by the dentist as they are more brittle and can break down. So to maintain and restore a tooth structure, crown placement is usually done.