There are three main possibilities for toothache: caries, pulpitis and periapical periodontitis. Filling treatment is recommended for the former, and root canal treatment is recommended for the latter two. 1. Dental caries: mainly manifested as pain after hot and cold water into the cavity, the pain disappears immediately after the stimulus is removed, and the caries can be found not reaching the pulp during the examination, which can be directly filled after removing the carious tissues. 2. Pulpitis and periapical inflammation: the main manifestation is pain after hot and cold stimulation, the pain continues after the stimulation is removed, patients with pulpitis also have spontaneous pain, pain at night and other symptoms, patients with periapical inflammation have occlusal pain and so on. It is mainly caused by caries spreading to the pulp, and all of them need root canal treatment to remove the infected pulp and dentin, and then the final filling or crown restoration can be carried out. It is recommended that patients with toothache should seek treatment as early as possible to avoid delays.