title: The effects of surgical expansion of the maxillary arch and its consequences for the incisor axis.
abstract: OBJECTIVE
  Reduced transverse maxillary dental arch width may be treated either by surgically supported rapid maxillary expansion (SRME) with conservative orthodontic appliances or by means of Le Fort I osteotomy (LFIO). Both are means of transverse maxillary expansion.
  
  
  METHODS
  Both surgical methods (SRME and LFIO) were evaluated with regard to the presurgical and postsurgical form of the maxillary dental arch and its consequences for the incisor axis by means of 32 dental casts and cephalometric analysis.
  
  
  RESULTS
  In both groups, anterior and posterior dental arch width showed significant changes after surgery, but changes in anterior dental arch width were less significant after LFIO (p = 0.004) than after SRME (p < 0.000; t-test). Cephalometric analysis (OK1/N1) did not show any significant differences between the two surgical methods (p = 0.1266; t-test). Anterior arch length was not reduced after LFIO but significantly reduced after SRME. Thus, the ideal elliptical shape of the dental arch was lost in the SRME group, which may impede esthetic outcome of the maxillary dental arch.
  
  
  CONCLUSIONS
  Le Fort I osteotomy achieving direct transverse expansion should be favored over surgically supported rapid maxillary expansion if transverse expansion does not exceed 7 mm.
authors.affiliation: Department of Cranio-Maxillo-Facial Surgery, Paracelsus Medical University Nuermberg, Breslauerstr. 201, 90471 Nuermberg, Germany; Department of Cranio-Maxillo-Facial Surgery, University Medical Center, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Moralis
authors.affiliation: Department of Cranio-Maxillo-Facial Surgery, University Medical Center, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Zitzmann
authors.affiliation: Department of Cranio-Maxillo-Facial Surgery, Paracelsus Medical University Nuermberg, Breslauerstr. 201, 90471 Nuermberg, Germany. Electronic address: Martin.Gosau@klinikum-nuernberg.de.
authors.forename: M
authors.initials: M
authors.lastname: Gosau
authors.affiliation: Department of Cranio-Maxillo-Facial Surgery, Paracelsus Medical University Nuermberg, Breslauerstr. 201, 90471 Nuermberg, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Schlegel
mesh_terms: D000328:Adult; D002508:Cephalometry; D003724:Dental Arch / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000601:surgery*; D019340:Osteotomy, Le Fort; D010155:Palatal Expansion Technique; D012189:Retrospective Studies; D055815:Young Adult
keywords: Anterior and posterior arch width; Cephalometric analyses; Le Fort I osteotomy; Surgically supported rapid maxillary expansion