Pulp disease is divided into the following categories: 1. Reproducible pulpitis: Reproducible pulpitis is the filling of the pulp with clinical manifestations of transient pain, which can be relieved when the irritant is removed and the vitality of the pulp can be preserved; 2. Irreducible pulpitis: This includes acute pulpitis, chronic pulpitis and retrograde pulpitis. Acute pulpitis manifests itself as very severe pain, which is generally unbearable. Chronic pulpitis is pain caused by prolonged cold, hot, sour or sweet stimulation, sometimes with spontaneous pain or even nocturnal pain, but it does not manifest itself violently. Retrograde pulpitis is the endodontic symptoms caused by periodontal disease through the root canals and apices of the periapical area. Early on, it is caused by periodontal disease and has no clinical symptoms, which may manifest as tooth discoloration or fistulas, etc.