The material of the crown of a single tooth (is a tooth grinding small, make a thing like a sleeve to wrap the tooth). Large classification: 1, all-metal crowns 2, metal porcelain crowns (the inner layer is metal, the outer layer is porcelain, high temperature porcelain baked to metal) 3, all-porcelain crowns Choice principle one: the teeth can be seen, that is, involving aesthetics, can do porcelain and full magnetic; not involving aesthetics and can not see the teeth can do metal Choice principle two: the amount of grinding of their own teeth: all-porcelain > porcelain > metal, of course, the less teeth grinding the better. Choice principle three: the degree of aesthetics: all porcelain > porcelain > metal to say a few specific choice: 1, if the teeth behind can not see, these three teeth can be, if not consider the aesthetic, metal teeth the most cost-effective. Because metal teeth do not have the problem of chipped porcelain, longer life, the least amount of grinding their teeth. 2, front teeth: metal teeth can not be used. Porcelain teeth can meet the aesthetic requirements of most people, some patients with higher requirements can choose all-porcelain teeth, because all-porcelain teeth are very realistic, no gum discoloration problem. The metal in porcelain teeth can cause gum darkening and blackening. However, all-porcelain teeth are slightly more abrasive than porcelain teeth, and porcelain teeth are more suitable if the teeth are smaller. All-porcelain teeth are more expensive than porcelain teeth.