Teeth will be sensitive to cold and heat performance is the phenomenon of dentin allergy, the phenomenon can be caused by the teeth damaged cryptic cracks, teeth surface damage, periodontitis, excessive wear and tear of the teeth and other factors. 1. Hidden cracks on damaged teeth: when the teeth are damaged, the surface of the teeth will not be affected, but the inner part of the teeth will have hidden cracks and gradually increase in size, and when it increases to the extent that it affects the dentin, it will cause dentin allergy to heat and cold. 2. Wear and tear of tooth surface: when teeth experience trauma or caries, the dentin tubules will be exposed on the outside of the teeth, which will cause pain when exposed to hot and cold stimuli. 3. Periodontitis: when periodontal tissues undergo repeated inflammatory stimulation, it will lead to atrophy of the tooth root, and the tooth root will be exposed on the outside, which will lead to sensitization of the dentin of the tooth root, which will cause pain when subjected to too cold or too hot stimuli. 4. Excessive wear and tear of teeth: Grinding teeth while sleeping can lead to excessive wear and tear of teeth, causing the dentin tubules at the roots to be exposed to the outside tissues, which can lead to excessive sensitivity and discomfort when experiencing cold and hot stimuli. In order to alleviate this symptom as soon as possible, it is recommended to go to the hospital stomatology department for standardized and effective treatment.