Root canal treatment is a treatment process for tooth, pulp and apical lesions. Indications for root canal treatment: First, caries, hidden fracture, crown fracture, malformed central cusp, excessive wear, retrograde infection from periodontal disease, pulpitis caused by accidental pulp penetration and pulp necrosis that cannot preserve the living pulp. Second, apical lesions caused by continued development of pulpitis, failure of dry cadaver plastination treatment, retrograde infection of periodontitis. Third, degenerative changes of the pulp caused by unknown reasons, such as intracanal resorption and pulp stone causing pathological changes of the pulp.