Porcelain crowns generally last about 10 years. Porcelain crowns are made by stacking porcelain powder on the surface of a metal base crown and then baking it at high temperature. Due to the inconsistent contraction of metal and porcelain powder, the porcelain layer is prone to chipping. At the same time porcelain crowns and gum contact, the metal ions released will form a black line, can affect the aesthetic. Patients with porcelain teeth can not chew hard objects, otherwise the stress concentration will cause the porcelain layer to fracture, exposing the metal surface and affecting aesthetics. Porcelain layer defects will destroy the shape of the jaw, can affect the chewing function, with a long time chewing, the thinner base of the crown will be abraded to form a perforation, will cause caries of the abutment teeth, thus shortening the service life. When wearing porcelain teeth for the first time, there is a mild discomfort, the patient should be patient to practice the use, and gradually adapt. At the same time when wearing porcelain teeth for the first time should also avoid eating too cold, too hot food, so as not to cause excitation pain, about two weeks later can eat normally.