title: Impact of adenotonsillectomy on the dentofacial development of obstructed children: a systematic review and meta-analysis.
abstract: BACKGROUND
  Dentofacial deformities frequently require orthodontic treatment. Understanding of preventable risk factors is essential for reducing treatment need. Upper airway obstruction (for example due to hypertrophic adenoids and/or tonsils) has been hypothesized to be a risk factor.
  
  
  OBJECTIVE
  This systematic review aimed to reflect the contemporary evidence on the risk of obstruction by hypertrophic adenoids and/or tonsils, by assessing the dentofacial changes after adeno- and/or tonsillectomy.
  
  
  METHODS
  A systematic search of electronic databases and manual searches of grey literature and reference lists of relevant studies was performed.
  
  
  METHODS
  No restrictions were placed on publication language. Experimental, cohort, and case-control studies were eligible for inclusion. Studies reporting associations between treatment of adenoid and/or tonsil hypertrophy and dentofacial deformities in children were included. Adenoidectomy and/or tonsillectomy were performed in all patients; outcomes were assessed before and after surgery.
  
  
  METHODS
  Data were extracted by two independent reviewers in duplicate. The Cochrane Risk of Bias tool was used to assess the methodological quality of the included papers.
  
  
  RESULTS
  The initial search yielded 1196 papers, of which 16 articles could be included. All papers described controlled prospective cohort studies, reporting on a total of 461 patients and controls (mean age, 4.1-13.9 years). A descriptive and quantitative synthesis of dentofacial change postoperatively is presented. Consistent findings across studies were the normalisation towards labial inclination of the upper and lower incisors and towards a more horizontal mandibular growth pattern. No change in vertical or sagittal maxillary growth was reported after surgical treatment. Post-surgical increase in maxillary archwidth and decrease in lateral crossbite-frequency were consistently reported. Findings on overjet, overbite and angle from S to N to B (SNB-angle), mandibular arch width, and gonial angle were inconsistent.
  
  
  CONCLUSIONS
  The available literature suggests that treatment of hypertrophic adenoids and/or tonsils affects dentofacial deformity. This could indicate a relationship between nasopharyngeal obstruction (i.e. upper airway obstruction) and the dentofacial growth pattern. However, the high risk of bias and considerable diversity between studies impedes a clear conclusion regarding this effect.
  
  
  BACKGROUND
  None.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Leiden University Medical Center, Leiden, The Netherlands.|Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Division Clinical Methods and Public Health, University of Amsterdam, Faculty of Medicine (AMC), The Netherlands.
authors.forename: Bibi E
authors.initials: BE
authors.lastname: Becking
authors.affiliation: Department of Oral and Maxillofacial Surgery, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Jop P
authors.initials: JP
authors.lastname: Verweij
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Division Clinical Methods and Public Health, University of Amsterdam, Faculty of Medicine (AMC), The Netherlands.|Stichting Bijzondere Tandheelkunde, Amsterdam, The Netherlands.
authors.forename: Sonja M
authors.initials: SM
authors.lastname: Kalf-Scholte
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Division Clinical Methods and Public Health, University of Amsterdam, Faculty of Medicine (AMC), The Netherlands.
authors.forename: Cees
authors.initials: C
authors.lastname: Valkenburg
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Division Clinical Methods and Public Health, University of Amsterdam, Faculty of Medicine (AMC), The Netherlands.
authors.forename: Eric W P
authors.initials: EWP
authors.lastname: Bakker
authors.affiliation: Department of Oral and Maxillofacial Surgery, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: J P Richard
authors.initials: JPR
authors.lastname: van Merkesteyn
mesh_terms: D000233:Adenoidectomy; D000234:Adenoids / Q000473:pathology; D016022:Case-Control Studies; D006801:Humans; D006984:Hypertrophy / Q000601:surgery; D007180:Incisor / Q000254:growth & development / Q000473:pathology; D008310:Malocclusion / Q000628:therapy; D008334:Mandible / Q000254:growth & development / Q000473:pathology; D008437:Maxilla / Q000254:growth & development / Q000473:pathology; D008445:Maxillofacial Development; D014066:Palatine Tonsil / Q000473:pathology; D011446:Prospective Studies; D014068:Tonsillectomy