Some people do not pay much attention to missing teeth, especially 1-2 teeth, they think that if one side of the teeth is missing, the other side is available; if the back teeth are missing, the front teeth can be used. In fact, if teeth are not set for a long time after extraction, it will bring many effects to the whole oral and maxillofacial system: 1, chewing function is reduced, the missing part can not bite, which affects the digestion and absorption of food. 2, because of individual teeth missing, long time without restoration will make the oral tissue change, affecting the alignment of the whole mouth, often manifested as adjacent teeth to the missing area tilt to make the gap smaller, the opposite jaw teeth elongation, resulting in early contact or interference, thus leading to disorder of the bite jaw relationship; serious cases often caused by a tooth missing a side of the tooth waste, so that the incidence of periodontal disease, caries increased significantly. 3, cause periodontal tissue lesions, missing teeth for a long time, adjacent teeth to the missing teeth tilt, the opposite jaw teeth elongation caused by food embedding, followed by periodontal disease. Fourth, the loss of front teeth often affects the aesthetics and pronunciation, language is formed in the oral cavity, front teeth mainly affect the accuracy of pronunciation of dental sounds (eat, poetry, know) labiodental sounds (divide, fly, put) lingual sounds (de, special, difficult). In addition, tooth loss can cause lesions in the temporomandibular joint, with severe problems such as restricted mouth opening, joint pain, and joint popping. Therefore, patients who have had their teeth extracted are advised to follow the doctor’s instructions for timely placement of dentures. In addition to individual missing teeth, most missing teeth, and missing teeth in the whole mouth, dead pulp teeth with large crown caries and residual roots can also be restored to tooth form and function through restoration after proper treatment, therefore, the residual roots and crowns should not be extracted rashly, and it is better to ask the restorer to see if they have retention value. Generally speaking, you need to wait for 2-3 months after tooth extraction before you can set the teeth, when the wound is completely healed, the alveolar bone resorption and reconstruction is completed, and the denture is more stable after setting the teeth.