title: Relapse after rigid fixation of mandibular advancement.
abstract: In 19 subjects rigid fixation of bilateral sagittal split osteotomies was used for mandibular advancement. Five angles and four linear measurements were determined cephalometrically for two time intervals: before surgery to immediately after surgery (T1-T2), and immediately after surgery to six months to one year after surgery (T2-TL). A multiple regression analysis with a backward stepping procedure was used to determine relationships between relapse, as defined by the position of pogonion at T2-TL (PgT2) and B point during this same time interval (BT2). The only significant predictor of PgT2 was PgT1 (P less than 0.001) (amount of advancement of pogonion during the time interval T1-T2). When BT2 was examined, both the change in position of B point at T1-T2 (P less than 0.001) and the change in anterior facial height at T1-T2 (P less than 0.02) were significant predictors of relapse. There were no other predictors of relapse. Advancements of 6 to 7 mm or greater as measured at B or Pg deserve special attention as they were more predisposed to relapse. Methods for preventing relapse are discussed.
authors.forename: J E
authors.initials: JE
authors.lastname: Van Sickels
authors.forename: A J
authors.initials: AJ
authors.lastname: Larsen
authors.forename: W J
authors.initials: WJ
authors.lastname: Thrash
mesh_terms: D001863:Bone Screws; D002508:Cephalometry; D002680:Chin / Q000601:surgery; D005544:Forecasting; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology; D008334:Mandible / Q000033:anatomy & histology / Q000601:surgery*; D010027:Osteotomy / Q000295:instrumentation / Q000379:methods*; D012008:Recurrence