Failure to seal the cavity after root canal treatment may be acute pulpitis, acute periapical periodontitis, pulp necrosis and so on. 1. Acute pulpitis: When the cavity is not sealed after root canal treatment, the pulp is swollen and congested with loose tissue. Grinding open the pulp cavity can reduce the pressure and slow down the pain. 2. Acute periapical inflammation: opening the pulp cavity and placing a medicinal twist can make the exudate and pus from the root tip discharge into the mouth through the root canal to relieve the pressure on the root tip and relieve the pain with minimal trauma to the periapical tissues. 3. Pulp necrosis: teeth that are not sealed after root canal treatment may be affected teeth with pulp necrosis, there are a large number of bacteria and toxins in the root canal, if not effectively controlled, the closed lumen of the canal will allow bacteria to rapidly spread to the periapical tissues, which can lead to the emergence of more serious pain. During this period, it is recommended that you do not eat hard foods and report any discomfort or unusual pain to your doctor.