title: Stability of large maxillary advancements using a combination of prebent and conventional plates for fixation.
abstract: OBJECTIVE
  The purpose of this study was to determine the stability of one and two jaw maxillary advancements fixed with prebent plates and "L"-shaped plates.
  
  
  METHODS
  Twenty-six patients met the inclusion criteria (group 1: one jaw [14]; group 2: two jaws [12]). Radiographs were digitized before surgery (T1), immediately after surgery (T2), at 6 weeks (T3), and at 6 months (T4). Stability was assessed comparing A-point movement and change in palatal plane. t tests were used for comparisons between groups, and linear regression analysis was used to assess the stability of A-point T2-T4 versus A-point movement T1-T2 and changes in the palatal plane T1-T2.
  
  
  RESULTS
  Initial A-point movement between the two groups was significant (group 1 = 7.61 ± 1.73; group 2 = 5.22 ± 1.67) (P = .0002). Both showed relapse (group 1 = 0.78 ± 0.95; group 2 = 0.04 ± 0.49). Although there was no significant relationship between initial A-point movement and relapse, there was a significant negative relationship between change in palatal plane and relapse in group 1. When initial A-point movement and change in palatal plane were combined, as both increased, relapse also increase (P = .007; R2 = 0.41).
  
  
  CONCLUSIONS
  Prebent plates used with "L" plates are a stable fixation technique. Relapse increases with large advancements and change in palatal plane (posterior impaction).
authors.affiliation: Fellow, Division of Oral and Maxillofacial Surgery, University of Kentucky, Chandler Medical Center University of Kentucky, Lexington, Kentucky, USA; ESHA Oral & Cranio-maxillofacial Surgery, Giza, Egypt.
authors.forename: Marwa
authors.initials: M
authors.lastname: Ragaey
authors.affiliation: Provost Distinguished Service Professor, Assistant Dean of Hospital Dentistry, and Professor of Oral and Maxillofacial Surgery, Division of Oral and Maxillofacial Surgery, University of Kentucky, Lexington, KY, USA. Electronic address: vansick@email.uky.edu.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Van Sickels
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks; D001860:Bone Plates; D002508:Cephalometry; D005260:Female; D006801:Humans; D008297:Male; D008313:Malocclusion, Angle Class III / Q000601:surgery*; D008437:Maxilla / Q000000981:diagnostic imaging / Q000601:surgery*; D063166:Maxillary Osteotomy / Q000379:methods*; D056948:Orthognathic Surgical Procedures; D019340:Osteotomy, Le Fort / Q000379:methods*; D011474:Prosthesis Design; D016896:Treatment Outcome