When a tooth is left with a root, it is important to go to the clinic for a specific examination to determine if the root is of restorative and therapeutic value. If the root is long enough, the root is strong, and there is no extensive inflammation at the root tip, this root can be preserved, but first a root canal is performed to remove the infected pulp, clean and flush the pulp chamber, and then the pulp chamber is tightly filled to control the inflammation. In addition, a fiber pile is placed in the root canal cavity and a resin core is molded on top of the fiber pile. Finally, the tooth is prepared on the basis of the resin core and a porcelain or all-ceramic crown is restored. If the root is very short, there is very little remaining tissue, the broken end is located deep below the gum, and the root is loose or the root surface is fractured, and the root tip is extensively shadowed, it is recommended that the root be extracted as soon as possible, followed by a fixed denture, implant denture, or removable denture.