Mandibular fractures are the second most common fractures of the face after the nasal bone. Mandibular symphyseal/parasymphyseal fracture comprises 15.6 to 29.3% of mandibular fractures. Tooth loss in the fracture line is a known phenomenon, but space loss has not been evaluated comprehensively in the literature. In a retrospective study, patients with mandibular symphyseal/parasymphyseal fractures, who had been treated from 2012 to 2013 in Mashhad University, Iran, Emdadi Hospital, were recalled. Patients with mandibular incisor tooth/teeth loss were included in the study. Space loss, the technique used to replace the lost tooth/teeth, upper and lower dental midline relationship, combination fracture or fractures in other facial skeleton, and type of treatment were evaluated. Of 98 patients with mandibular symphyseal/parasymphyseal fractures, 22.5% had incisor tooth/teeth loss. In this group, 73% had space loss. Only four patients had replaced the lost tooth/teeth. Dental midlines did not match each other in patients whose feature was evaluated. Open reduction and internal fixation with miniplates were used in symphyseal/parasymphyseal fractures except one. Space loss after mandibular symphyseal/parasymphyseal fracture with incisor tooth loss is a common error. The most important factor to prevent complications related to space loss following mandibular symphyseal/parasymphyseal fracture accompanying incisor tooth loss is space preservation.