A tooth that stops hurting when exposed to cold may be the result of the cold relieving localized inflammation, causing the pain to slow down or temporarily disappear. Cold relief usually occurs after acute pulpitis and gingival papillitis. Acute pulpitis is a common clinical oral disease, often caused by severe dental caries. Typical clinical manifestations are severe toothache, which can be aggravated at night, and the degree of pain is aggravated by heat stimulation, and the pain can be relieved by cold in the initial stage, which is due to the increase of pressure in the pulp cavity when it is hot, and the decrease of pressure when it is cold. When acute pulpitis occurs, it is necessary to use open pulp drainage and decompression, and carry out perfect root canal treatment. Gingival papillitis can also occur when the pain is reduced by cold. There may be other reasons why a tooth does not hurt when exposed to cold. However, the absence of pain in the cold is usually temporary, regardless of the cause of the toothache, we should consult a doctor as soon as possible to clarify the cause of the disease, and standardized treatment.