title: Thin-plate spline analysis of mandibular morphological changes induced by early class III treatment: a long-term evaluation.
abstract: OBJECTIVE
  To evaluate the long-term mandibular morphological changes induced by early treatment of class III malocclusion with rapid maxillary expansion (RME) and facial mask (FM).
  
  
  METHODS
  Twenty-five subjects [10 boys, 15 girls; mean age at T1 (start of treatment) 9.3±1.6 years] with class III disharmony were treated with RME and FM therapy followed by fixed appliances. The patients were re-evaluated at the end of growth (T2), about 8.5 years after the end of the treatment (mean age, 18.6±2.0 years). Sixteen subjects with untreated class III malocclusion comprised the control group. Mandibular shape changes were analysed on the lateral cephalograms of the subjects of both groups by means of thin-plate spline (TPS) analysis. Procrustes average mandibular configurations were subjected to TPS analysis by means of both cross-sectional between-group comparisons at T1 and at T2 and longitudinal within-group comparisons. Statistical analysis of shape differences was performed using a generalized Goodall F test.
  
  
  RESULTS
  In the long term, the treated group exhibited a significant upward and forward direction of condylar growth. On the contrary, untreated class III subjects showed an upward and backward direction of condylar growth associated with a downward and forward deformation of the mandibular symphysis.
  
  
  CONCLUSIONS
  Limitations are related to the small sample size of both treated and control groups and to the retrospective nature of the study.
  
  
  CONCLUSIONS
  Early treatment of class III malocclusion with RME and FM is able to produce significant and favourable long-term mandibular shape changes characterized by an anterior morphogenetic rotation.
authors.affiliation: *Department of Surgery and Translational Medicine-Orthodontics, University of Florence, Florence, Italy,**Department of Orthodontics and Pediatric Dentistry, University of Michigan, Ann Arbor, USA, lorenzo.franchi@unifi.it.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Franchi
authors.affiliation: ***Department of Orthodontics, The University of Rome 'Tor Vergata', Rome, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Pavoni
authors.affiliation: ***Department of Orthodontics, The University of Rome 'Tor Vergata', Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Cerroni
authors.affiliation: ***Department of Orthodontics, The University of Rome 'Tor Vergata', Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Cozza
mesh_terms: D059925:Anatomic Landmarks / Q000473:pathology; D002508:Cephalometry / Q000706:statistics & numerical data; D002648:Child; D003430:Cross-Sectional Studies; D005115:Extraoral Traction Appliances; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008313:Malocclusion, Angle Class III / Q000628:therapy*; D008334:Mandible / Q000254:growth & development / Q000473:pathology*; D008335:Mandibular Condyle / Q000254:growth & development / Q000473:pathology; D010155:Palatal Expansion Technique / Q000295:instrumentation; D012189:Retrospective Studies; D055502:Secondary Prevention