The stump is caused by the total loss of the crown of the tooth for various reasons, and only the root is retained, which may or may not be visible clinically under the gingiva. The main reason for stumps is caries, from the beginning of a cavity in the crown, slowly develops into a crown, the crown continues to carry out caries, slowly becomes a stump, which is the main reason. Another more common cause is trauma, after a tooth has been subjected to various types of trauma, its crown may break off due to external forces, leaving only the root in the alveolar bone. There is also a relatively rare situation that when the tooth is extracted in the clinic due to various reasons, part of the root may not be removed from the alveolar bone, leaving a little stump at this time, which is relatively rare, but also occurs occasionally in the clinic.