Relapse and stability after mandibular setback surgery one year postoperatively: a retrospective study.

Purpose: A retrospective evaluation was performed of dentoalveolar and skeletal stability 1 year after mandibular setback surgery using intraoral vertical subcondylar osteotomy (IVSO) combined with intermaxillary fixation.

Patients And Methods: Twenty-eight patients (16 men, 12 women) with skeletal Angle Class III malocclusions were included. Mean age at start of treatment was 23.9 years. All patients underwent combined surgical and orthodontic treatment. Dental casts and cephalometric measurements were performed for each patient before orthodontic treatment and at 8 weeks and 1 year after surgery.

Results: Treatment changes from 8 weeks to 1 year after surgery were small but significant for the angular relationship between the maxilla and the mandible in the sagittal plane (ANB) (mean difference, -0.5 mm; P = .021), Wits appraisal (mean difference, -0.7 mm; P = .044), the inclination of the mandible in relation to the nasion-sella line (ML-NSL) (mean difference, -0.8 mm; P = .010), and the inclination of the lower incisors in relation to the nasion-point B line (Li-NB) (mean difference, -0.6 mm; P < .001). These findings for cephalometric values indicated a small skeletal relapse in sagittal and vertical relations. No significant dentoalveolar relapse occurred according to the dental cast evaluations.

Conclusion: The results clearly show that orthodontic treatment combined with IVSO provides a stable dental and skeletal result 1 year after treatment.