Teeth touch cold water on the pain, it is likely to be the following two cases: First, there are caries, caries once the development of deep dentin will cause hot and cold sensitivity, can be completely cured by filling treatment. Second, dentin hypersensitivity, dentin hypersensitivity is likely to be caused by heavy tooth wear, or enamel defects in the neck of the tooth, this time according to the area of the defects to consider whether to carry out medicated desensitization treatment, or resin-based materials for the protection of the filling treatment. In addition to these two possibilities, we should also be alert to the possibility of chronic pulpitis, chronic pulpitis will make the tooth has had night pain, spontaneous pain, if the tooth did not have any pain, basically can be ruled out the possibility of chronic pulpitis.