Teeth are usually discolored after root canal treatment. 1. Root canal treatment is a common treatment in dentistry, eliminating infection through mechanical and chemical non-methods, making the root canal clean and shaped, and then the technique of sterilizing and filling the root canal with medication to prevent re-infection, which can maintain the integrity of the natural tooth arrangement and prevent the displacement of neighboring teeth and periodontal disease. 2. It is suitable for the treatment of apical periodontitis and irreducible pulpitis, which can relieve symptoms such as toothache and chewing disorders. The maintenance time of root canal treatment can be up to 10 years or more, but root canal treatment does not really improve the oral environment. Moreover, the pulp and nerve of the tooth are completely removed after root canal treatment, the tooth will gradually become weaker, which is easy to cause cavities or discoloration, so crown restoration is recommended after root canal treatment. 3. After root canal treatment, care should be taken not to use the affected tooth to chew harder and stickier food, so as not to cause tooth fracture. It is recommended that patients choose regular medical institutions for root canal treatment to avoid the adverse effects caused by improper operation.