Apical periodontitis rarely results in sensory impairment of the inferior alveolar nerve. This article describes the Vincent symptom and documents a clinical case of this neurological disorder, in which paraesthesia as well as hypaesthesia of the mental nerve were caused by apical periodontitis of a first mandibular molar. The healing process and the long-term results, 2 years following non-surgical root canal treatment, are presented. Keywords: apical extrusion, inferior alveolar nerve, paraesthesia, Vincent symptom