Pain after filling a cavity, clinically known as post-filling pain, is a condition that is not uncommon in clinical practice. Generally, there are two reasons as follows: 1. the pulp is stimulated by the repair material, it can be observed for a period of time, if the pain is gradually relieved and finally disappeared, then the stimulation is considered to be transient, and no further treatment is needed after the pain is relieved and disappeared; 2. there is a mistake in judging the pulp when repairing the decayed tooth, and the symptoms of pulpitis have already appeared, but the tooth is only repaired as a caries without root canal treatment. If this is the case, the only way to repair the tooth is to remove the repair material, and then to carry out pulp opening and systematic root canal treatment.