Metal porcelain crown bridge has become the main method of restoring a few missing teeth in the mouth, but the fixed crown bridge may appear broken after wearing for a period of time. Analysis of the causes and prevention methods: 1, metal retainer wear perforation: may be due to the lack of space for jaw surface preparation, poor wear resistance of the material or easy corrosion. Carefully observe the amount of preparation on each side when preparing the tooth, and choose stronger and more corrosion-resistant materials as much as possible. 2, the bridge body bending sinking: mostly due to poor mechanical strength of metal bridge materials, or bridge design improper, such as long span of the bridge, the combined force is large, did not use measures to enhance the strength of the bridge. 3, the connection body desoldering or broken: desoldering mostly due to welding technology or welding material has problems. If the whole building bridge, mostly due to improper design of the connection body, such as insufficient thickness or the formation of slits at the connection. 4, porcelain fracture and peeling: porcelain’s biggest disadvantage is brittle, defects are most likely to trigger porcelain crack or porcelain peeling. (1) improperly designed metal bridge production, so that its strength is not enough to cause bridge deformation; or bridge surface there are sharp angles, sharp ridges or connections at the body presents v-shaped slits; or gold porcelain junction is located in the concentration of joint force parts; or bear the maximum joint force at no metal substrate support. (2) porcelain layer is too thick, porosity increase or porcelain layer is too thin, will reduce the strength of porcelain. (3) improper surface treatment of metal bridges (including grinding, roughening, cleaning, de-gassing and pre-oxidation), reducing the strength of the gold porcelain bond. (4) plastic porcelain or sintering in the problem, such as porcelain paste porcelain particles condensation is not enough, into the furnace or out of the furnace too quickly, or repeated sintering, etc. (5) occlusion imbalance, there is jaw interference, resulting in stress concentration. In addition, trauma or bite hard objects when the combined force is too large may cause porcelain cracking, porcelain flaking. Fixed bridge breakage, the cause should be analyzed, generally need to be removed and redone. Smaller chipped porcelain available light-curing resin bonding cover. In short, for this kind of problem is important to prevent.