Removable partial denture, commonly known as removable denture or removable prosthesis, refers to the use of the remaining natural teeth and mucous membranes in the mouth to obtain retention and support, the patient can remove and wear a kind of restorations; it is fixed on the remaining natural teeth through the ring, and at the same time, the use of the base bracket so that the denture to maintain the appropriate position to exercise the masticatory function, and can be removed and worn on their own. Wide range of application It can repair the defects in any part of the teeth and alveolar ridge, and the number of missing teeth can range from one tooth to many or even the whole mouth. For partial or total loss of teeth, a variety of removable partial denture repair or full denture repair can be carried out, such as continuous casting of metal bracket type removable denture, taiji buckle and other attachment denture, titanium metal bracket denture. Through theoretical research and technical improvement, the retention problem of full denture has been basically solved, and full denture can be set for patients with poor oral conditions, including full denture restoration of full maxillary defects. Advantages and disadvantages Removable partial denture has the advantages of less abrasion of dental tissues, easy to wash and brush, can better keep the oral cavity clean, easy to repair and replenishment, etc.; base bracket fracture or add artificial teeth and other problems can be transformed in the original denture; the production of the equipment required for the production of a simple, simple production, the cost is relatively low. For the case of more missing teeth, removable partial denture repair is often used. The disadvantage is repeated removal and wearing, and metal rings. The aesthetics of the anterior teeth is slightly worse. In addition, removable denture volume, more parts, the first time patients often have a foreign body sensation, affecting pronunciation, and even cause nausea, and chewing function is not as good as fixed denture. Third, classification 1, plastic base activity denture denture and denture connected to the base are made of plastic. Beautiful color, similar to the mucous membrane, easy to operate, inexpensive, light weight, easy to repair and lining, but the base is thicker, a strong sense of foreign body, the base is easy to fracture when the force is large. Temperature conduction is poor, and it is not easy to white clean. Clinical application is the most widely used. 2, casting metal bracket activity denture whole casting bracket type removable partial denture usually also known as activity denture, is the most commonly used method of dental defects repair, the method is the use of natural teeth and abutment covering mucosa and bone tissue support, relying on the denture retainer and abutment of the retaining role of artificial teeth to restore the shape and function of the teeth and the abutment material to restore the defective teeth of the crater ridge and the soft tissue morphology, the patient can take off and wear the patient themselves. A kind of prosthesis. A cast removable partial denture usually consists of four parts: artificial teeth, abutments, retainers and connectors. The cast removable partial denture has a wide range of indications and is suitable for patients with a wide range of tooth loss, especially for patients with missing teeth at the free end. The denture base is basically made of metal, which is relatively thin and has little foreign body sensation. The main force part of the base tray is made of metal casting, the advantages of higher strength, not easy to fracture, small volume and thin, patients wear more comfortable, good temperature conduction; disadvantages of the operation is more complex, grinding workload, the need for a certain amount of equipment, and repair and add the complementary more difficult. However, due to its obvious superiority, it has become a particularly wide range of activities for restoration, especially for the free end of the missing, which is made of metal casting as a whole, hard and durable, thin and light, avoiding the traditional plastic denture of the heavy feeling, according to the different materials cobalt-chromium alloy bracket, titanium alloy bracket, titanium bracket, gold-plated bracket and so on.