Bite force measurement in mandibular parasymphyseal fractures: a preliminary clinical study.

We measured the amount of bite force generated by patients treated for parasymphyseal fractures of the mandible by open reduction and internal fixation at various predetermined time intervals. Sixty volunteers ranging from 18 to 60 years old were selected as the control group. All measurements were made on a bite force measurement device with the head in an upright position and in an unsupported natural position. Bite forces were measured at the incisor and right and left molar regions. These bite forces were compared with six patients with isolated mandibular unilateral parasymphyseal fractures. All patients were operated using open reduction and internal fixation using two miniplates at the fracture site. In the volunteer group, bite forces ranged from 22 to 50 kg in the molar region and 3 to 27 kg in the incisor region. Mean adult healthy values (male and female) in the molar region were 36 kg and in the incisor region, 15 kg. In mandibular parasymphyseal fractures, incisor bite forces were reduced significantly when compared with the control group in the first 2 postoperative weeks and regained significantly thereafter till 4 to 6 weeks. Bite forces in the molar region took ~6 to 12 weeks to regain maximum bite forces when compared with the volunteer group. Restoration of functional bite forces was evident by 6 to 8 weeks. However, the restoration of maximum bite forces may require up to 12 weeks in parasymphyseal fractures.