If a toothache reoccurs after a filling, it is considered to be due to pulpitis or periapical inflammation, both of which can be controlled and relieved by root canal treatment. Root canal treatment is a simple procedure that uses machinery to clean the root canal, disinfect and sterilize it, and then place a local filling, which protects the tooth and reduces tooth damage. After a filling and then a toothache, the filled tooth needs to be reopened and cleaned, and then rinsed in the root canal, medicine, sealing treatment, can further prevent periodontal disease. After root canal treatment in order to prevent the material from falling out and the tooth splitting, you can choose to do crown restoration. After surgery, we should also pay attention to oral hygiene, adhere to morning and evening brushing, rinsing after meals, can effectively prevent dental caries.