Fixed crowns and bridges are a type of restoration that uses natural teeth as a base and is cemented to the natural teeth by a retaining device that cannot be removed by the patient. For patients with tooth loss and a few missing teeth, in addition to the traditional gold alloy and cobalt-chromium alloy metal casting crowns and fixed bridges, in order to meet the increasing aesthetic requirements of patients, our department has developed porcelain fused metal crown and bridge, all-ceramic crown and bridge, castable glass-ceramic crowns, high aluminum porcelain crowns and other restorations, so that the restorations are closer to the physiological requirements in terms of morphology, color and aesthetics. 1, characteristics 1, the denture received all the dental force through the abutment teeth to the periodontal support tissue, rather than rely on the alveolar ridge of the missing tooth area to bear. The way of conduction is similar to that of natural teeth; 2. The denture is stable, unchanged and well supported when exercising the chewing function, so it has high chewing efficiency; 3. 1. Metal crowns and bridges: According to the different metals used, they are divided into common alloy, precious metal alloy, pure titanium metal, etc. 2, porcelain crowns, bridges: porcelain from the early nineteenth century has been used, it is a good material, with hard and wear-resistant, smooth surface, good color, stable chemical properties, insoluble in saliva and the advantages of good histocompatibility. It is a more ideal restoration for both missing anterior and posterior teeth, which can achieve the ideal function and form for restoring missing teeth. It is first made of alloy metal base, and then covered with low-fusing porcelain powder similar to natural teeth, sintered and fused in a vacuum high-temperature firing furnace, so porcelain fused metal crowns have the strength of metal crowns and the aesthetics of porcelain crowns. Its characteristics are to restore the function of the tooth description, strong resistance to fracture and color, realistic appearance, smooth surface, wear resistance, will not be deformed, stable color, acid and alkali resistance, is a lifelong restoration. 3, all-porcelain crown: Although porcelain teeth have been able to achieve the effect of almost fake, but the metal porcelain teeth is opaque restorations, in strong light its color effect is not very ideal, the use of all-porcelain restorations can solve this problem. Ceramic materials have beautiful, good biocompatibility and color stability, is an important material for dental restoration, all-porcelain crowns have good chemical stability, long-term in the oral cavity under the action of various foods, drinks, saliva, body fluids, microorganisms and their enzymes, will not deteriorate, denaturation. And has excellent biocompatibility, no metal porcelain combined with loose roughness, reduce plaque aggregation, reduce gingival edge redness and atrophy. All-porcelain crowns because of the high surface gloss, good transparency, with similar aesthetic effect with natural teeth, no metal porcelain gingival margin translucent green, black line and discoloration problems, has been welcomed by many patients, can provide the best choice for the majority of beauty lovers. At present, all-ceramic restoration has been widely carried out in the Department of Restorative Dentistry clinical, and has won the praise of the majority of patients.