RESUMEN
Introduction: the needle fracture during the inferior alveolar nerve block is not a common accident, but whenit occurs can cause great inconvenience to the professional and patient, because the surgical removal shouldonly be performed without risk of sequelae to the patient. Aim: relate a case of broken dental needle duringinferior alveolar nerve block and the needle fragment dislocation to the skull base becoming impossible itssurgical removal. Described preventive procedures to avoid that complication with anatomical considerationsrelated to the inferior alveolar nerve block. Case report: a young female, 18 years old required care afterfracture of the dental needle during inferior alveolar nerve anesthesia. She was submitted to CT scan thatdetermined the impossibility of surgical removal of the fragment because it has migrated to the skull basebecoming close to vital anatomic structures because its could produce irreparable sequelae such loss of tonguesensation and movement of the lip. A conservative treatment was offered. Conclusions: surgical removal ofits instrument should be correctly evaluated to avoided irreparable sequelae to the patient. The knowledgeof anatomical structures in the pterigomandibular region may reduce the risk of injury to nerves and anotherstructures and prevent further complications.