title: Craniofacial morphology and adolescent facial growth in Pierre Robin sequence.
abstract: BACKGROUND
  The purpose of this research was to analyze craniofacial morphology and adolescent facial growth in subjects with Pierre Robin sequence (PRS). The research was conducted at the Center for Craniofacial Care and Research at The Hospital for Sick Children, Toronto, Ontario, Canada, and the Burlington Facial Growth Research Center, Faculty of Dentistry, University of Toronto.
  
  
  METHODS
  Longitudinal lateral cephalometric tracings of 34 Caucasian subjects with nonsyndromic PRS were compared with those of unaffected control subjects, matched for age, sex, and ethnicity, and representing the range of occlusions in an untreated population. Cephalometric measurements were obtained before orthodontic treatment (age, 11.8 years) and after orthodontic treatment but before any surgical treatment (age, 16.6 years). Between-group differences of craniofacial measurements were analyzed with paired t-tests, and longitudinal growth differences were analyzed with analysis of variance (ANOVA) adjusted for the growth interval.
  
  
  RESULTS
  Significant differences were noted, with the PRS group showing smaller cranial base length, shorter maxillary and mandibular lengths, increased palatal and mandibular plane inclinations, and more open mandibular flexure. Mandibular body length and height were smaller as were ramal length and width, anterior basal thickness, and chin thickness. The ramus-to-body ratio was greater. With growth, greater gains in anterior face and symphyseal height were seen, but the mandible showed less closure of its internal flexure. The maxilla and the mandible remained retrusive during adolescent growth, and the maxilla became more retrognathic. Mandibular morphologic differences persisted in spite of additionally adjusting for cranial base length in the analysis.
  
  
  CONCLUSIONS
  Subjects with PRS had reduced cranial base and maxillary and mandibular lengths. Mandibular deficiency was most pronounced in the body. Due to bimaxillary retrognathism, the maxillomandibular dysplasia was not significant. A vertical growth pattern worsened the profile. There was no evidence of adolescent mandibular catch-up growth.
authors.affiliation: University of Toronto, The Hospital for Sick Children, Ontario, Canada. sunjaysuri@hotmail.com
authors.forename: Sunjay
authors.initials: S
authors.lastname: Suri
authors.forename: R Bruce
authors.initials: RB
authors.lastname: Ross
authors.forename: Bryan D
authors.initials: BD
authors.lastname: Tompson
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D016022:Case-Control Studies; D002508:Cephalometry / Q000706:statistics & numerical data; D002648:Child; D003818:Dentition, Mixed; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008334:Mandible / Q000254:growth & development / Q000473:pathology*; D008437:Maxilla / Q000254:growth & development / Q000473:pathology*; D008445:Maxillofacial Development; D009971:Orthodontics, Corrective; D010855:Pierre Robin Syndrome / Q000473:pathology* / Q000503:physiopathology* / Q000628:therapy; D015203:Reproducibility of Results; D063173:Retrognathia / Q000473:pathology; D012189:Retrospective Studies; D019291:Skull Base / Q000473:pathology*