The dangers of porcelain teeth include tooth sensitivity, gray gums, and gingivitis. Porcelain teeth in the tooth preparation, if the tooth wear is relatively large, there will be tooth allergy, hot, cold, sour and sweet stimulation pain, if the distance from the dental nerve is relatively close, there will be spontaneous pain. Porcelain crowns if the use of non-precious metals, this material is weak corrosion resistance, metal ions precipitation will appear gray gums, gum inflammation, etc., serious allergic reactions. Porcelain teeth will have a certain effect when MRI is performed again due to the metal material itself. Therefore, it is recommended to use all-ceramic materials. Therefore, the harm of porcelain teeth mainly comes from tooth preparation and porcelain crown metal materials, strictly control the amount of tooth preparation, try to choose precious metal materials or all-ceramic crown restoration.