We report an unusual case of anatomical changes of the mandibular canal, displacement of a tooth fragment and postoperative inferior alveolar nerve neurosensory deficits after removal of a mandibular third molar. This article analyses the possible cause of anatomical changes of the mandible canal and make a contribution to studies in the literature about nonsurgical treatment of displaced tooth fragment and Low Level Laser therapy of postoperative inferior alveolar nerve neurosensory deficits after removal of a mandibular third molar.