All-porcelain teeth is what the people usually say braces, is a relatively safe way to restore teeth, the harm is only a damage to the tooth itself, basically harmless to the human body. All-porcelain teeth cover the surface of the tooth crown, no metal base crown, and closer to the color of the tooth, because of the absence of metal, will not discolor the gums. And there is essentially no effect when MRI is performed. All-porcelain teeth also have certain hazards, is due to the fact that all-porcelain teeth need to grind away more of the hard tissue of the tooth during the tooth preparation process. The outermost part of the tooth is the enamel, which has no sensory function but is a protective dental hard tissue. When the enamel is worn away, the dentin inside is exposed. The dentin has many dentin tubules that lead to the pulp tissue. External hot, cold, sour and sweet stimuli will be transmitted to the dental nerve through the dentin tubules, so there will be painful sensations when eating hot, cold and sweet foods, which is the common clinical dentin allergy. If the nerve is continuously stimulated, it may cause pulpitis, including painful eating, or spontaneous pain and nighttime pain, difficult to sleep or awaken from sleep pain, requiring root canal treatment of the tooth. Therefore, the danger of all-ceramic teeth is the irritation of the tooth nerve during tooth preparation, which may cause pulpitis and requires related treatment by an experienced doctor.