If the tooth is painful after being exposed to heat or cold, but the pain is short-lived, the tooth has reached the level of moderate caries and needs to be filled in a timely manner. During the filling treatment, some medication can be given to protect the pulp, and then resin-based materials can be used to fill the tooth. After the filling, the patient should try to avoid using too stimulating food for three months, which may cause pulpitis in the affected teeth. If the pain lasts for a long time, even for a few minutes, after the tooth has been exposed to cold or hot pain, the tooth is considered to have chronic pulpitis, and X-rays need to be taken to clarify the location of the caries and the nerve. If the pulp cavity has been reached, the pulp needs to be opened in time for root canal treatment. The reason why we need to receive root canal treatment is that the bacteria have already invaded the pulp, and if the filling is hastily carried out, the symptoms of acute pulpitis with severe pain are likely to appear in the later stage.