If the dental nerve is not taken cleanly, patients will have occasional cold, hot, sour, sweet, occasional sensitivity symptoms or intermittent painful and stabbing sensations, and some patients will be afraid to bite and have painful bite. When this occurs, patients are advised to go to the dentistry department for root canal retreatment in a timely manner. It is usually necessary to take an X-ray to observe the root filling or root canal treatment. If the nerve is not taken cleanly, the symptoms will become more and more serious afterwards, so it is necessary to take the nerve cleanly and remove the infected material, necrotic pulp and a series of dirty things in the root canal in time, and then carry out root canal filling thoroughly, and it is better to make a restoration crown.