The main causes of frequent toothache are as follows: 1, decay, if the cavity is relatively large, this is when the tooth defect is very close to the pulp chamber, once eating hot and cold, irritating food or having food embedded in the cavity, it will cause frequent painful tooth pain. 2, there is a hidden crack on the tooth surface, when the crack of the tooth penetrates the tooth enamel to reach the dentin, if you bite food with this tooth it will cause frequent 3, periodontal disease, mostly seen in patients with more serious periodontal disease, these patients due to the resorption of the alveolar bone so that the root of the tooth exposed in the mouth, thus causing tooth sensitivity or even pain, teeth will gradually loose, unable to bite hard objects. 4, chronic pulpitis, mostly used for decay or trauma caused by dental nerve infection. Chronic pulpitis can cause recurrent pain to the tooth in response to external stimuli, and the pain is usually intense and even accompanied by spontaneous pain. 5, periapical periodontitis, periapical periodontitis will lead to long-term swelling and discomfort of the tooth root tip, and inflammation and swelling pain.