Root canals are usually unblocked using a lubricant or by ultrasound, depending on the situation. If this is not effective, palliative care is the only option. 1. Lubrication. Root canal blockage may be caused by the root canal being too curved and small, or the root canal being blocked by the wrong method. Generally, a small drill with lubricant is used to slowly unblock the root canal. 2. Ultrasound. Root canal blockage can also be caused by the separation of instruments or the deposition of calcified material, you can use ultrasound under the microscope to vibrate out the separated instruments or use vibration to remove the calcified material in the root canal. 3. Palliative treatment. If the root canal cannot be unblocked and there is no apical inflammation, the canal can be filled directly and then observed. If the root canal is impassable, it is recommended that the cause of the impassable root canal be clarified, and then the root canal should be treated according to the situation.