Pain caused by tooth decay is mostly caused by decay that has invaded the nerve or root base of the tooth and needs to be treated by root canal therapy. Root canal treatment, also known as endodontic treatment, is a technique to treat endodontic and periapical disease by eliminating the sources of irritation in the pulp cavity, especially in the root canal, including infected or inflamed pulp, infected dentin, bacteria and their metabolites, and by tightly closing the root canal with filling material to treat endodontic disease and prevent the occurrence of periapical lesions or promote the healing of periapical lesions. The procedure preserves the tooth and is thus complementary to tooth extraction. Root canal treatment usually consists of three basic steps: root canal preparation, root canal disinfection, and root canal filling. Root canal preparation and root canal disinfection effectively remove the infected material from the root canal and prepare a good shape for root canal filling. The purpose of root canal filling is to maintain the effect of root canal cleaning and to prevent the occurrence of microleakage. Root canal treatment is suitable for all types of endodontic and periapical lesions. Pulpal necrosis, chronic pulpitis (including periapical granuloma, periapical abscess, and periapical cyst), endodontic periodontal syndrome, and systemic diseases that are not suitable for extraction but require treatment or temporary retention of the affected tooth are all indications for root canal treatment. When performing root canal treatment, there are two methods. Two or more times method: First, make a cavity to open the pulp, rinse the pulp cavity, remove the necrotic and gangrenous pulp, enlarge the root canal, rinse the root canal again to clean it, aspirate it and seal it with antiseptic medicine for about 2-7 days; if there is no obvious reaction, remove the seal and fill the root canal; if there is obvious reaction, reseal the antiseptic medicine and fill the root canal next time. One time method: make a cavity to open the pulp, flush and enlarge the root canal, and then fill the root canal in one time. During or after root canal treatment, there may be temporary discomfort, which is usually relieved by taking anti-inflammatory or analgesic drugs, and local swelling and pain should be informed to the doctor. Root canal treatment is a treatment process for tooth, pulp and apical lesions. Root canal treatment is a treatment method to prevent periapical lesions or promote healing of periapical lesions by removing necrotic material from the root canal, disinfecting it appropriately, and filling it to remove the undesirable stimulation of the root canal contents to the periapical tissues. There are many causes of toothache, if you have questions, click on the “Dental Consultation” below for initial consultation, if you need treatment, you must go through a face-to-face professional oral examination and diagnosis before symptomatic treatment.