Patient: Description of the condition (onset time, main symptoms, hospital, etc.): Between May and June 2010, due to a hole in the teeth in the Zibo Central Hospital Department of Stomatology, and then do the nickel alloy porcelain braces, wear when the doctor said the braces are too high, so the porcelain polished off part of the top, leaving the nickel alloy exposed. Is it harmful to my health if the nickel alloy is exposed when the porcelain on the surface of the braces is polished away? Doctor: nickel-chromium alloy porcelain crown metal crown is composed of nickel, chromium, beryllium and other metals, with the development of material knowledge and update, understand that beryllium has a certain degree of toxicity, that is, “biocompatibility” poor, the human body has certain adverse effects; nickel, this metal composition, according to textbooks, there is a certain percentage of the population will occur Nickel, a metal component, according to the textbook, can also cause allergy to a certain percentage of the population. At present, in view of the adverse characteristics of beryllium, there is a nickel-based alloy porcelain crowns, the metal in addition to the beryllium component, but the nickel component is still in. I do not know what kind of composition of your porcelain crowns for metal crowns? If the nickel-based porcelain crown metal exposure, always not too good. It is recommended to remove the re-molded production.