1.Activated denture is suitable for missing more than 2 posterior teeth or more than 4 anterior teeth; missing teeth without abutment support; teeth adjacent to the missing area are not parallel; remaining abutment teeth with short clinical crowns; remaining abutment teeth with poor periodontal support; and the presence of obvious alveolar bone atrophy; or patients with poor physical condition or limited economic conditions. 2.Fixed bridge restoration of missing teeth is chosen and accepted by the majority of patients for its comfort, good restoration function and long-term stability. Fixed bridges are suitable for healthy abutment teeth on both sides of the missing teeth, small gap span, and can provide sufficient retention after clinical crown preparation. At present, there are very few healthy teeth are worn out clinically for fixed bridge restoration, for the missing teeth on both sides of the adjacent teeth are dead pulp teeth need to do crown or patients can choose fixed bridge restoration due to health or economic factors. 3. Implant prosthesis is suitable for all kinds of missing teeth, such as the neighboring teeth cannot provide enough support for conventional fixed bridge restoration, lack of abutment support in the missing teeth, edentulous jaws and other situations are suitable for implant restoration. Patients with systemic diseases such as hypertension, coronary heart disease, diabetes, thyroid disorders, etc. need to control the systemic condition within the normal range to consider implant restorations. Implant restorations are not recommended for patients with bone metabolic diseases, long-term use of immunosuppressive drugs, glucocorticoids, and maxillofacial radiotherapy.