A porcelain tooth, known as a porcelain-fused-to-metal full crown, is an ideal restoration. It is made of alloy metal base, and then covered with porcelain powder similar to natural teeth, sintered and fused in a vacuum, high-temperature porcelain furnace. The types of porcelain teeth are divided into the following categories according to the material of the inner crown: 1, ordinary metal porcelain crown: the advantage is cheap, a wide range of indications. Containing metal components, the impact of MRI, especially ordinary metal porcelain teeth, even need to be removed to do MRI examination. Because of the characteristics of metal opaque, in the front teeth restoration, ordinary porcelain teeth have unnatural color and dark disadvantages; 2, precious metal porcelain teeth: the advantages of biocompatibility is relatively good, chemically stable, very beautiful. The disadvantage is the metal content, the greater impact on MRI; 3, zirconia all-porcelain crown: the most ideal restorative material in the oral cavity at this stage is zirconia all-porcelain crown, the disadvantage is the higher requirements for the conditions of the abutment teeth, more expensive, but zirconia does not belong to the metal material, overcome all the shortcomings of metal porcelain teeth, no impact on MRI, no periodontal, gum stimulation, biocompatibility is very good It has good aesthetics and can simulate natural teeth more realistically.