title: Permanent tooth agenesis in non-syndromic Robin sequence and cleft palate: prevalence and patterns.
abstract: OBJECTIVE
  Partial tooth agenesis is frequently observed in Robin sequence. Tooth anomalies are increasingly considered as an extended phenotype of the cleft palate population. The study objective was to compare the prevalence and patterns of tooth agenesis in a group of patients with non-syndromic Robin sequence (ns-RS) and a group with non-syndromic cleft palate (ns-CP).
  
  
  METHODS
  The panoramic radiographs of 115 ns-RS and 191 ns-CP patients were assessed for agenesis of the permanent dentition (excluding third molars) and the patterns recorded using the Tooth Agenesis Code.
  
  
  RESULTS
  Partial tooth agenesis was observed in 47.8% of ns-RS and 29.8% of ns-CP patients with a greater prevalence in the mandibula than in the maxilla, particularly in ns-RS. The teeth most frequently absent in both groups were the mandibular second premolars and maxillary lateral incisors. Tooth agenesis was bilateral in two-thirds of affected ns-RS patients and one-half of ns-CP patients. In ns-RS, bilateral agenesis of the mandibular second premolars was more frequently observed in female than that in male patients. Completely symmetrical patterns of hypodontia were found in around 45% of ns-RS patients with tooth agenesis compared to 35% in ns-CP. No association was found between the extent of the palatal cleft and the severity of hypodontia.
  
  
  CONCLUSIONS
  Tooth agenesis is more prevalent in ns-RS than that in ns-CP, demonstrates a much greater predilection for the mandible in ns-RS, and bears no relation to the extent of the palatal cleft.
  
  
  CONCLUSIONS
  When compared to ns-CP, additional developmental disturbances are likely involved in the etiology of tooth agenesis in ns-RS. Future research could help identify the underlying genetic traits and aid in classifying patients in those with and without expected tooth agenesis in order to facilitate orthodontic management strategies.
authors.affiliation: Department of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
authors.forename: Anneline
authors.initials: A
authors.lastname: de Smalen
authors.affiliation: Cleft Center Utrecht, Division of Plastic and Reconstructive Surgery, Wilhelmina Children's Hospital, University Medical Center Utrecht, Heidelberglaan 100, PO Box 85500, 3508 GA, Utrecht, The Netherlands. d.p.f.vannunen@gmail.com.
authors.forename: Daan P F
authors.initials: DPF
authors.lastname: van Nunen
authors.affiliation: Department of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
authors.forename: Ruurd R
authors.initials: RR
authors.lastname: Hermus
authors.affiliation: Department of Orthodontics, Sophia Children's Hospital, Erasmus University Medical Center, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands.
authors.forename: Edwin M
authors.initials: EM
authors.lastname: Ongkosuwito
authors.affiliation: Department of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
authors.forename: Arjen J
authors.initials: AJ
authors.lastname: van Wijk
authors.affiliation: Department of Plastic, Reconstructive and Hand Surgery, VU University Medical Center Amsterdam, De Boelelaan 1117, Postbus 7057, 1007 MB, Amsterdam, The Netherlands.
authors.forename: J Peter W Don
authors.initials: JPWD
authors.lastname: Griot
authors.affiliation: Cleft Center Utrecht, Division of Plastic and Reconstructive Surgery, Wilhelmina Children's Hospital, University Medical Center Utrecht, Heidelberglaan 100, PO Box 85500, 3508 GA, Utrecht, The Netherlands.
authors.forename: Corstiaan C
authors.initials: CC
authors.lastname: Breugem
authors.affiliation: Department of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
authors.forename: Gem J C
authors.initials: GJC
authors.lastname: Kramer
mesh_terms: D000848:Anodontia / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000473:pathology*; D002648:Child; D002972:Cleft Palate / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D010641:Phenotype; D010855:Pierre Robin Syndrome / Q000473:pathology*; D015995:Prevalence; D011862:Radiography, Panoramic
keywords: Cleft palate; Etiology; Hypodontia; Robin sequence; Tooth agenesis