Pulpitis should be promptly treated with pacification or root canal therapy. Pulpitis is classified as acute pulpitis, chronic pulpitis and reversible pulpitis. They are based on the clinical presentation of the disease. Acute pulpitis is the result of an acute attack of chronic pulpitis, which has an acute onset and often results in nocturnal pain and severe pain, which requires pulp opening to relieve pressure. When the acute inflammation is controlled, routine root canal treatment is performed. Chronic pulpitis is a chronic symptom of bacterial infection of dental nerve, the tooth has dull pain or painful eating. The decayed tooth tissue is removed, the infected nerve is extracted, then the root canal is disinfected and finally the root canal is filled. Repeatable pulpitis is a transient reaction of the tooth to an external stimulus, the pathological change is pulp filling. The stimulus is removed and the pain is able to disappear immediately. Sometimes the decayed tooth tissue is removed and the tooth can be treated with pacification, the surface of the pulp tissue is covered with pulp capping agent and observed for a period of time, and if there are no subjective symptoms, the tooth can be treated with filling. So pulpitis can be treated with root canal, or nerve preservation treatment, and in severe cases it needs acute phase of opening.