A carious tooth is characterized by a substantial defect, which can be seen as a black hole with the naked eye. However, in some parts of the tooth, it is not easy to find “holes” in the early stage, but only black color. Depending on the depth of the hole, there may be a variable degree of pain response to hot, cold, sour and sweet stimuli, but in the early stages, this response is not obvious and can easily be overlooked. Caries treatment method is routinely filling. The main materials are silver amalgam or resin-based materials. Silver amalgam is stronger and more wear-resistant, but the color is not consistent with the teeth, affecting aesthetics, because it is not bonded to the teeth, the need to grind the tooth tissue is more; while the resin material is similar in color to the teeth, bonded to the teeth, and less grinding of the tooth tissue, but the material is slightly more expensive, and the material may be with the growth of time and discoloration, aging. When the tooth is deeply decayed, it cannot be filled directly, it is necessary to remove the decayed tissue first, and then seal the medicine and observe it, do not stimulate it with too hot or too cold food during the period, and then fill it permanently after two weeks when the tooth does not show any pain and other symptoms. If there is obvious pain in the tooth after filling, it should be dealt with in time at the hospital. When caries progresses to endodontics or periapical disease, the treatment of choice is root canalization. That is, the infected pulp (tooth nerve) is completely removed and the root canal is tightly closed to permanently eliminate the lesion. Due to differences in equipment and skill levels, some doctors tend to be incomplete in endodontic treatment, resulting in recurrence of the disease. During root canal treatment, a dental radiograph should be taken before, during and after the procedure to get an accurate picture of the treatment and to understand the treatment and its effect, so as not to plant hidden dangers during the procedure. Many teeth that begin to swell and hurt again soon after root canal treatment may be the result of imperfect root canal treatment and need to be redone. Caries is a disease that can recur. After treatment, you should still maintain good oral hygiene and go to the hospital for regular checkups to prevent the recurrence of caries.