If the broken root is within 2 mm and there is no periapical inflammation. The extraction wound is also well healed and the root tip forms a bony healing with the alveolar bone. There are no complications. Especially when extracting the maxillary posterior teeth, the root tip is close to the maxillary sinus, so it is easy to cause more trauma if it is forcibly removed, and also when extracting an obstructed third molar, if the broken root is close to the inferior alveolar nerve canal, it is easy to damage the inferior alveolar nerve when removing it with improper force, causing numbness of the lower lip. If the extracted tooth has periapical inflammation, it will cause infection if it is not removed, or if the broken root is not in the original alveolar socket, it must be removed, otherwise it will also cause infection and cannot form bony healing. When the broken root enters the maxillary sinus or the posterior pharyngeal wall, it must be removed, otherwise it will also cause infection, swelling and pain, and cannot heal.