There are many friends with unattractive teeth, do porcelain teeth and anterior teeth aesthetic restoration, when done very satisfied, but a few years later appeared gum blackening, this situation is very common. There are several reasons for the blackening of teeth: 1, the first few years with more metal porcelain restorations, especially nickel-chromium alloy, in the oral cavity in the case of moisture, will be corroded, causing the gums to blacken; 2, most of the gums blackened is not because the tooth metal is formed after corrosion. Such as some doctors do preparation, there is not prepared in place, such as the edge should be hidden under the gums can not see the edge, if the preparation of teeth against the gums, when wearing teeth, the teeth border and dentures junction color is difficult to do exactly the same, contrast, feel the gums black, resulting in visual error; 3, some patients after the porcelain teeth, the gum condition is not good, there will be a slight inflammation, gums will be black. Therefore, if you encounter blackened gums, you should consult a doctor in time to determine which is the case and make timely treatment.