Cause of early skeletal relapse after mandibular setback

Area of Science:

• Oral and Maxillofacial Surgery
• Orthodontics
• Skeletal Biology

Background:

• Mandibular setback osteotomy is a surgical procedure to correct mandibular prognathism.
• Skeletal relapse can occur post-surgery, particularly during intermaxillary fixation.
• Understanding relapse factors is crucial for predictable surgical outcomes.

Purpose of the Study:

• To investigate factors contributing to skeletal relapse after mandibular setback osteotomy.
• To identify the primary cause of postsurgical superior shift of the gonial region.
• To determine methods for enhancing stability following mandibular setback surgery.

Main Methods:

• Cephalometric analysis of fifteen patients undergoing modified sagittal split ramus osteotomy.
• Evaluation of postsurgical superior shift of the gonial region as a relapse parameter.
• Correlation analysis between surgical technique variables and observed relapse.

Main Results:

• Inadvertent anteroposterior rotation of the proximal segment significantly correlated with skeletal relapse.
• The extent and pattern of distal segment repositioning showed less correlation with relapse.
• Superior shift of the gonial region was observed despite skeletal suspension wiring.

Conclusions:

• Proximal segment rotation is a key factor in skeletal relapse after mandibular setback.
• Preserving the proximal segment's original anatomic position is vital for stability.
• Combining proximal segment preservation with skeletal fixation ensures predictable outcomes.