Long-Term Study of Relapse After Mandibular Orthognathic Surgery: Advancement Versus Setback

Area of Science:

• Orthognathic Surgery
• Craniofacial Surgery
• Dental and Skeletal Relapse

Background:

• Relapse following orthognathic surgery is a complex process requiring long-term evaluation.
• Understanding relapse patterns is crucial for managing patient expectations and treatment outcomes.

Purpose of the Study:

• To evaluate and compare short-term and long-term skeletal and dental relapse after mandibular advancement (MA) and mandibular setback (MS) surgeries.
• To investigate the correlation of relapse with factors such as gender, age, surgical movement amount, and intra-operative changes.

Main Methods:

• Retrospective analysis of 46 patients undergoing MA (n=26) or MS (n=20) surgery.
• Lateral cephalograms analyzed at pre-surgery (T0), 1-week post-surgery (T1), 1-year post-surgery (T2), and minimum 5-years post-surgery (T3).
• Evaluation of horizontal, vertical, and angular skeletal and dental parameters for relapse.

Main Results:

• Significant relapse observed in all studied parameters from short-term (T1-T2) to long-term (T2-T3) follow-up in both MA and MS groups.
• Mandibular setback (MS) surgery demonstrated significantly higher horizontal, vertical, and angular relapse compared to mandibular advancement (MA) surgery.
• Relapse correlated positively with the amount of surgical movement and intra-operative change in mandibular plane angle.

Conclusions:

• Both MA and MS surgeries are associated with significant short-term and long-term relapse.
• MS surgery exhibits a higher degree of relapse compared to MA surgery.
• Surgical movement magnitude and intra-operative mandibular plane angle changes are key factors influencing relapse.