title: A retrospective analysis of the stability and relapse of soft and hard tissue change after bilateral sagittal split osteotomy for mandibular setback of 64 Taiwanese patients.
abstract: OBJECTIVE
  This study was an analysis of the soft and hard tissue changes of the facial profile after bilateral sagittal splitting osteotomy for mandibular setback of Taiwanese patients.
  
  
  METHODS
  We collected pre- and postsurgical lateral cephalographs of 64 patients (28 males, 36 females) with skeletal Class III malocclusion who received combined orthodontic-surgical treatment with bilateral sagittal splitting osteotomy mandibular setback at Taipei Veterans General Hospital between 1994 and 2000. Nineteen cephalometric parameters of (14 linear, 4 angular, and the BS index) soft and hard tissues were measured at 1 week before treatment, and 2 months and 1 year after surgery, and analyzed by paired t test.
  
  
  RESULTS
  Mean patient age was 20.0 +/- 1.6 years. The patients underwent an average of 7 mm mandibular setback at the osseous pogonion (Pog). Average setbacks at Pog and soft tissue pogonion (pog) were 5.54 mm and 4.85 mm, respectively, at 1 year after surgery. The setback ratio of Pog/pog was 1:0.88. The hard tissue relapse at Pog was 21% at 1 year after surgery. Improvement in prognathic profile was demonstrated by significant changes in the positions of Pog and pog, ANB angle, the distance from lower lip to esthetic line (E-L lip), and the BS index after surgery. However, compared with parameters obtained from a normal Taiwanese population, the cephalometric data of Pog, pog, and BS index still indicated mild prognathism.
  
  
  CONCLUSIONS
  Although mandibular prognathism could be grossly improved by bilateral sagittal splitting osteotomy mandibular setback, a significant amount of relapse occurred within 1 year after surgery. The extent of the postoperatively preserved features showing mandibular prognathism should be a concern for both patients and physicians.
authors.affiliation: Department of Dentistry, Taipei Veterans General Hospital, School of Dentistry, National Yang-Ming University, Taiwan, ROC.
authors.forename: Joe I-Chiang
authors.initials: JI
authors.lastname: Chou
authors.forename: Hwai-Jen
authors.initials: HJ
authors.lastname: Fong
authors.forename: Shou-Hsin
authors.initials: SH
authors.lastname: Kuang
authors.forename: Lin-Yang
authors.initials: LY
authors.lastname: Gi
authors.forename: Fang-Yi
authors.initials: FY
authors.lastname: Hwang
authors.forename: Yu-Chieng
authors.initials: YC
authors.lastname: Lai
authors.forename: Richard Che-Shoa
authors.initials: RC
authors.lastname: Chang
authors.forename: Shou-Yen
authors.initials: SY
authors.lastname: Kao
mesh_terms: D000328:Adult; D002508:Cephalometry; D002680:Chin / Q000473:pathology; D005145:Face; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008046:Lip / Q000473:pathology; D008297:Male; D008313:Malocclusion, Angle Class III / Q000473:pathology / Q000601:surgery*; D008334:Mandible / Q000473:pathology / Q000601:surgery*; D008437:Maxilla / Q000473:pathology; D009666:Nose / Q000473:pathology; D010027:Osteotomy / Q000379:methods*; D011378:Prognathism / Q000473:pathology / Q000601:surgery; D012008:Recurrence; D012189:Retrospective Studies; D013624:Taiwan