The manifestations of unsuccessful root canal treatment mainly include dental defects, as well as infectious symptoms such as severe pain and sinus fistula in the treated area. Root canal treatment is often used for pulpitis, periapical infection, pulp exposure and other diseases, clinical surgery does not guarantee a 100% success rate, if there are symptoms suggesting that root canal treatment is unsuccessful, you can consider another surgical restoration. 1, dental defects: after root canal treatment, the tooth will gradually fuse with the filling as one, when there are tooth cracks, root fracture and other symptoms of incomplete teeth, it may be related to unsuccessful treatment 2, local infection: after root canal treatment, the painful symptoms of periodontal localization will generally be gradually reduced with time. However, if there is continuous severe pain, redness and swelling and other inflammatory symptoms at the treatment site, as well as increased pain when the tooth is chewed, it is usually due to unsuccessful root canal treatment. If the root canal is fractured, the drug cannot be continuously released, the inflammatory symptoms continue to worsen, and also lead to the formation of local abscesses, polyps or sinus tracts, fistulas, and the above symptoms still exist after treatment, indicating that the disease has not been cured, which is also generally considered to be a manifestation of unsuccessful root canal treatment; 3, other: after root canal treatment, there are still tooth sensitivity, tooth loosening, teeth can not play the normal chewing function, and normal closed mouth Symptoms such as obvious asymmetry of upper and lower teeth may also be due to unsuccessful root canal treatment.