Many patients due to a lack of knowledge of oral diseases, teeth with caries for too long did not get timely treatment, or trauma and other reasons, resulting in one or more teeth in the oral cavity crown missing, only the root of the tooth (referred to as stumps). Some people think that stumps are useless and it is better to pull them out and set them in place, but this is not the case. After the doctor’s examination, some of the roots can be retained, and these retained roots often have an important role in the subsequent veneer. Ji Ping, Department of Prosthodontics, Shandong University Stomatology Hospital Usually those roots with sufficient length, not much looseness, no periapical lesions on X-rays, or periapical lesions that have been cured after perfect root canal treatment, and no significant horizontal resorption of the periapical bone can be preserved. The preservation of residual roots is of great importance to the results of restorative dentistry in the later stages of the patient’s life. First of all, for the root length is enough for the root of the residual root, can be directly set on the root of the fixed denture, which is what we call the pile core crown restoration. This kind of fixed denture has no foreign body sensation, good comfort level, high aesthetics, and can reach the degree of fake to real, and, due to the retention of the tooth root, chewing from the root to the nerve center of the proprioception has not been damaged, so that the denture to eat with the feeling of eating with their own real teeth, the effect of restoration is good. Secondly, for those stumps whose roots are not long enough to set fixed dentures, preserving the stumps can maintain the fullness of the alveolar bone, especially the anterior teeth, so that the alveolar bone will not shrink because of the extraction of teeth, avoiding the appearance of the soft tissues of the lips due to the atrophy of the alveolar bone subsidence of the face of the elderly. In addition, the design of some magnetic attachments and other retention devices on top of these stumps can greatly improve the restorative effect of removable dentures. At the same time, these roots can also be a certain degree of chewing proprioception to the nerve center, slowing down the resorption of the alveolar bone, conducive to occlusal force conduction, to prevent denture sinking, and improve the restorative effect. Therefore, treating the residual roots in the oral cavity with care, treating them as early as possible, preserving them, and maximizing their function is an issue to which each of us is responsible and to which we must pay attention.