Purpose: The aim of this article is to present a referred clinical case of an inferior alveolar nerve laceration during the insertion of a dental implant in the mandible, that came to our attention after the injury. Materials and methods: A 71-year-old female was treated by a colleague in order to be rehabilitated with a fixed implant-supported prosthesis for her missing teeth in positions 44, 45 and 46. After implant site osteotomy in region 46, the speed of the surgical motor was not changed; as a consequence, the implant was inserted at 1200 rpm and intruded into the mandibular canal, causing the laceration of the neurovascular bundle. Results: During the first 2 weeks after surgery the patient complained of paresthesia in the mental and lower lip area, with labial ptosis and drooling. After 14 days, the paresthesia reduced and mucosal and gingival normosensitivity was detected; however, the patient complained about hyperesthesia of the lower inside lip. After 21 days, the lower lip tone and function were almost completely restored and the paresthesia was further reduced, however the hyperesthesia persisted. Conclusions: It is extremely important to pay attention to preventing neurological complications through proper preoperative planning, careful execution of the surgical techniques and correct management of instruments and motor speed settings. The latter procedure should be double-checked by both the operator and the assistant. Palabras clave: complication, dental implants, mandibular nerve