Braces refer to fixed denture repair, mainly divided into two categories: 1, metal class porcelain teeth, lined with metal outside is porcelain. This kind of porcelain teeth when the need to do magnetic resonance and CT will have interference, so now the clinical has been gradually eliminated no longer used. 2, all-porcelain teeth, all-porcelain porcelain teeth relatively good results, without any adverse toxic side effects, CT imaging and magnetic resonance imaging are not any interference. In the all-porcelain crown, the better porcelain component is zirconium dioxide, relatively zirconium dioxide is harder more close to the hardness of the tooth, in addition to the taste is also better, the use of a long life, so it is recommended that if the patient has the conditions, you can do zirconia porcelain teeth.