The reasons for not recommending porcelain dentistry may be: wear and tear of the teeth, free metal ions, the risk of chipping, interference with MRI, etc. 1. Need to wear teeth: clinically, whether you do porcelain teeth or all-ceramic teeth, you need to grind the teeth according to a certain ratio before taking the mold to make dentures, so that the original healthy and intact dental tissues have been damaged, so there is a lack of teeth, generally not recommended to do porcelain teeth. 2. Metal ion free: Porcelain teeth are mainly used metal crowns and porcelain powder casting at high temperatures under the state of the combination of production, but some of the metal ions are unstable, under the action of oral saliva is prone to metal ions free of the problem, resulting in the gums edge of the adverse reaction of black, it is recommended that do not do porcelain teeth. 3. There is a risk of chipping: porcelain teeth is the outermost layer of porcelain powder layer, teeth in the process of chewing food if there is a concentration of stress or eating too hard food, it may lead to the porcelain layer of excessive force and the phenomenon of fracture and fall off. 4. Interference in the MRI: human cranium due to health checks need to carry out MRI, if there is metal in the oral cavity porcelain teeth, metal on the radiation blocking nature of the MRI results may produce a certain degree of interference, and even the need to remove the porcelain teeth in order to carry out the examination. Clinical reasons for not recommending porcelain teeth are generally the above reasons, in addition to other reasons, it is best to go to the dental hospital after consultation with the doctor.