title: Adaptation of lateral pterygoid and anterior digastric muscles after surgical mandibular advancement procedures in different vertical craniofacial types: a magnetic resonance imaging study.
abstract: OBJECTIVE
  Surgical mandibular advancement procedures induce major adaptations of jaw-closing muscles. In this study, adaptation of antagonist muscles, the lateral pterygoid (LPM) and anterior digastric (DigA) muscles, was evaluated.
  
  
  METHODS
  Eighteen adult patients with mandibular retrognathia and individually varying vertical craniofacial dimensions were treated with bilateral sagittal split osteotomies (BSSO), in some cases combined with a Le Fort I osteotomy (LF Bimax). The sample was divided into 1 short-face (SF, n = 7) and 2 long-face groups (LF BSSO, n = 3; and LF Bimax, n = 8). Pre- and postoperative maximum cross-sectional areas (CSA) and volumes were compared in these groups.
  
  
  RESULTS
  Postoperatively, CSA and volume of LPM increased in BSSO cases and decreased in bimaxillary cases. Inconsistent increases and decreases of CSA and volume of DigA were seen in all groups.
  
  
  CONCLUSIONS
  The LPM became larger in SF and LF BSSO patients and smaller in LF Bimax patients. The DigA adapted unpredictably.
authors.affiliation: Department of Oral and Maxillofacial Surgery/Pathology, Academic Center for Dentistry Amsterdam and VU University Medical Center, The Netherlands. dicker@xs4all.nl
authors.forename: Gertjan J
authors.initials: GJ
authors.lastname: Dicker
authors.forename: Peter H
authors.initials: PH
authors.lastname: van Spronsen
authors.forename: Floris C
authors.initials: FC
authors.lastname: van Ginkel
authors.forename: Jonas A
authors.initials: JA
authors.lastname: Castelijns
authors.forename: Ronald A
authors.initials: RA
authors.lastname: van Schijndel
authors.forename: Heleen P W
authors.initials: HP
authors.lastname: Boom
authors.forename: D Bram
authors.initials: DB
authors.lastname: Tuinzing
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D002508:Cephalometry; D016000:Cluster Analysis; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008334:Mandible / Q000601:surgery*; D019186:Mandibular Advancement / Q000379:methods*; D008445:Maxillofacial Development; D008875:Middle Aged; D009334:Neck Muscles / Q000033:anatomy & histology / Q000502:physiology*; D011626:Pterygoid Muscles / Q000033:anatomy & histology / Q000502:physiology*; D063173:Retrognathia / Q000601:surgery; D014716:Vertical Dimension