The tooth pain when drinking hot water is commonly caused by deep caries, reversible pulpitis, pulpitis, etc. It is necessary to visit the endodontic department of the hospital for detailed examination of the specific situation. If it is only deep caries, usually it is painful when encountering hot water, and it will return to normal in a short time after the stimulus is removed, and there is no spontaneous pain. In this case, it is recommended to fill the tooth as early as possible, and in general, we can use calcium hydroxide to cover the pulp indirectly, and then fill the tooth in layers. In addition, in the case of pulpitis, pain will occur not only when drinking hot water, but also spontaneous and paroxysmal pain, which is aggravated at night. Such cases cannot be filled directly and require root canal treatment before filling the tooth.