There is a tooth that is sore when touched, there are several possibilities: first, the tooth is hidden crack, which causes cracks in the tooth in the bite, then the tooth may touch the crack when touched, producing a sore feeling. If the pain is heavy, it is recommended to have porcelain braces to repair it. If the soreness is not very obvious, you can do desensitization or fill the tooth with resin after grinding out the cracks. Second, the tooth wear is heavy, when the dentin layer is exposed, it is easy to produce the phenomenon of tooth sensitivity, the symptoms of soreness when the tooth is touched, then you can fill the tooth or do porcelain full crown restoration. Thirdly, when the tooth is sore when touched, it may be due to mechanical damage, usually due to brushing too hard, incorrect brushing method, resulting in wedge-shaped defect of the tooth, which is easy to appear the phenomenon of cold, hot, sour and sweet sensitivity. Fourthly, deep caries, when the tooth is decayed, it is easy to produce food embedment pain, then it should be filled in time to avoid the phenomenon of nerve leakage.