The main reason why teeth are afraid of cold and heat is caused by dentin hypersensitivity, caries near the pulp, periodontal disease caused by the exposure of the neck of the tooth. 1. The surface of the teeth is covered by enamel, which can resist hot and cold sensitive stimuli. When the enamel wears away and exposes the dentin, the symptoms of hot and cold sensitivity and pain will occur. There are dentin tubules in the dentin, which can cause pain when encountering hot and cold stimuli, and the above symptoms can be relieved after dentin and tooth surface treatment. 2. Dental caries on the surface of the tooth, destroying the enamel, exposing the dentin underneath, deeper near the pulp, so that the dentin in the dentin dentin tubules are damaged, resulting in neural conduction can be caused by hot and cold sensitivity, the need for early dental repair can effectively alleviate its symptoms. 3. Gum recession caused by periodontal disease, root exposure, bacterial plaque stimulation of gum redness and swelling, bone atrophy and absorption can cause hot and cold sensitivity, the need for periodontal disease treatment, regular oral maintenance, the serious need for gingival reset surgery can be relieved. If there is tooth sensitivity, it is recommended to consult a doctor in time for examination and symptomatic treatment.