title: Physiological positioning strategy alters condylar position after mandibular ramus sagittal split osteotomies for mandibular prognathism.
abstract: OBJECTIVE
  The aim of this study was to elucidate the physiological position of the proximal segment for postoperative jaw movement in patients with mandibular prognathism.
  
  
  METHODS
  Twenty-two patients with mandibular prognathism were treated by orthognathic surgery using bilateral mandibular sagittal split ramus osteotomies (SSRO) with a physiological positioning strategy. The skeletal stability was assessed, and the movement of the proximal segment was evaluated by cephalography and computed tomography performed preoperatively, immediately postoperatively, and one year postoperatively.
  
  
  RESULTS
  The patients were divided into two groups: the stable group (SNB relapse <1.5°) and the relapse group (SNB relapse ≥1.5°). In the stable group at one year postoperatively, the average SNB relapse was only 0.29° (7%), the condylar head had moved posteriorly by 0.75 mm, and the proximal segment had rotated counterclockwise by 1.2°.
  
  
  CONCLUSIONS
  This new physiological positioning strategy improves the position of the condyle compared with the preoperative position in patients with mandibular prognathism.
authors.affiliation: a Department of Regenerative Oral Surgery, Unit of Translational Medicine , Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Seigo
authors.initials: S
authors.lastname: Ohba
authors.affiliation: b Department of Orthodontics and Dentofacial Orthopedics, Unit of Translational Medicine , Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Ozaki
authors.affiliation: a Department of Regenerative Oral Surgery, Unit of Translational Medicine , Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Kei-Ichirou
authors.initials: KI
authors.lastname: Miura
authors.affiliation: a Department of Regenerative Oral Surgery, Unit of Translational Medicine , Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Koga
authors.affiliation: a Department of Regenerative Oral Surgery, Unit of Translational Medicine , Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Kawasaki
authors.affiliation: b Department of Orthodontics and Dentofacial Orthopedics, Unit of Translational Medicine , Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Yoshida
authors.affiliation: a Department of Regenerative Oral Surgery, Unit of Translational Medicine , Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Izumi
authors.initials: I
authors.lastname: Asahina
mesh_terms: D000293:Adolescent; D000328:Adult; D002508:Cephalometry; D005260:Female; D006801:Humans; D008297:Male; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000502:physiology*; D059229:Osteotomy, Sagittal Split Ramus; D011378:Prognathism / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Physiological positioning strategy (PPS); condylar head; mandibular prognathism; orthognathic surgery; physiological position; proximal segment