LeFort I maxillary advancement: 3-year stability and risk factors for relapse

Introduction: The objectives of this retrospective cephalometric study were to assess the amount, direction, and timing of postoperative changes after LeFort I maxillary advancement, and to identify risk factors for skeletal relapse. Methods: The material was selected from the files at the Department of Orthodontics, University of Oslo, and comprised 43 patients who underwent 1-piece LeFort I advancement as the only surgical procedure from 1990 to 1998. All patients were followed for 3 years by using a strict data collection protocol. Lateral cephalograms were obtained before surgery and at 5 times after surgery. Results: A mean relapse of 18% of the surgical advancement occurred. In 14% of the patients, clinically significant skeletal relapse (≥2 mm) was observed. Most (89%) postoperative change occurred during the first 6 months after surgery. Skeletal relapse increased significantly with degree of surgical advancement (P = .001) and degree of inferior repositioning of the anterior maxilla (P = .004) (linear regression analysis). At the end of follow-up, overjet and overbite were within clinically acceptable ranges for all patients. Conclusions: Maxillary advancement with a 1-piece LeFort I osteotomy is a relatively stable procedure. Identified risk factors for horizontal relapse were degree of surgical advancement and degree of inferior repositioning of anterior maxilla.