If the filling hurts again, root canal treatment is needed if the tooth nerve is inflamed or if there is residual pulpitis. If the filling is too high, it can be adjusted. Filling is also called tooth filling, which is a one-time filling after tooth decay. In the process of removing the decayed tooth tissue, if the tooth nerve is exposed or the decay is closer to the tooth nerve, it will cause the inflammatory reaction of the tooth pulp tissue, which is pulpitis. The pain of pulpitis is very intense, and in severe cases, there will be pain from hot and cold stimulation and night pain. In this case, root canal treatment of the tooth is required. The infected nerve is first removed, then the root canal is disinfected, and a tight root canal filling is performed after the inflammation is controlled. If the pain occurs after root canal treatment, it may be due to residual pulpitis because some of the pulp was not completely removed during the treatment. If the filling is too high, it will also cause pain after filling, so it is necessary to adjust the bite. If the pain disappears after the adjustment, it can be observed without treatment, but if the pain continues, it is necessary to perform root canal treatment of the tooth. If the pain continues, root canal treatment is required. Therefore, root canal treatment is required to remove the nerve for a tight root canal filling or to adjust the bite.