Introduction Orofacial pain diagnosis is a difficult process. This article reports the case of a 38 y.o. patient experiencing severe acute facial pain of dental origin initially diagnosed as non odontogenic. Case Report The patient consulted at the dental emergency department for severe and frequent neuropathic-like paroxysmal pain attacks located in the anterior right maxilla. The pain fulfilled the ICHD3 criteria for Trigeminal Neuralgia (TN) of the right maxillary branch (V2) and responses to sensitivity tests were ambiguous due to severe allodynia. After one week of carbamazepine treatment (600mg/day), the patient was pain free except for a slight mechanical allodynia on tooth #12. Sensitivity tests revealed pulp necrosis and tomodensitometry revealed a rare developmental abnormality, dens invaginatus. Root canal treatment was performed. Results No recurrence of the pain was noted after 18 months without any medication. Conclusions Inflammatory pulpal pain may mimic TN, misleading experienced clinicians. Key words: Dens in dente, neuropathic pain, necrosis, diagnosis, atypical pain, endodontics.