A patient’s pain history is the primary source of information in case of toothache (dentoalveolar pain); revealing its location, its main characteristics and its course, both from the onset and during the day. Clinical diagnostic tests that provoke (such as pulp testing or percussion) or eliminate (such as local anaesthesia) pain are most useful. Several mechanisms may underlie dentoalveolar pain. Pain caused by pulpitis shows characteristics of visceral types of pain, whereas pain originating from the periodontal ligament is characterized by musculoskeletal features. It also happens fairly often that the pain is found to originate from a different tooth than the one in which it is perceived, or from an even more distant source (referred pain). These mechanisms emphasize the importance of differential diagnostics.