title: Asynchronous dentofacial development and dental crowding: a cross-sectional study in a contemporary sample of children in France.
abstract: BACKGROUND
  The causes of dental crowding are not fully understood, but it may result from an evolutionary trend towards reduced facial volume, without a proportional reduction in tooth sizes. Most previous studies conducted among modern humans have revealed a very low or non-existent correlation between tooth size and jaw size. Cross-comparison between dental age and facial skeletal age could help to provide better knowledge of the dynamic process of dental crowding. The primary objective of this research was to study the synchronism of dental maturation and skeletal facial growth in a sample of modern children living in France. The secondary objective was to assess the link between dentofacial asynchronism and dental crowding.
  
  
  RESULTS
  The random sample comprised 28 subjects (16 girls, 12 boys). Mean chronological age was 13.5 years (± 2.1; range 9.2-17.6). Mean dental age was 14.2 years (± 2.8; range 7.5-17) and mean facial skeletal age was 12.8 years (± 2.6, range 7-22). In the estimations of dental age and facial skeletal age, there was no evidence of systematic bias. There were 10 subjects (9 girls, 1 boy) with asynchronous dentofacial development. Finally, there were 13 subjects (8 girls, 5 boys) with dental crowding. A significant association was found between delayed facial skeletal growth/advanced dental maturation and dental crowding (P = 0.01).
  
  
  CONCLUSIONS
  Dental maturation and facial growth are not necessarily synchronous. Further understanding of the interactions between dental maturation and facial growth could have crucial implications in biological anthropology, as well as for the clinical practice of orthodontists. From an anthropological perspective, this study suggests that asynchronous dentofacial development could, at least partially, explain the frequency of dental crowding in modern populations.
authors.affiliation: Department of Orthodontics, Toulouse Dental Faculty, Paul Sabatier University, Faculté de Chirurgie Dentaire, (3 chemin des maraîchers), Toulouse Cedex 04 31062, France. wei.yanvergnes@gmail.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Yan-Vergnes
authors.forename: Jean-Noel
authors.initials: JN
authors.lastname: Vergnes
authors.forename: Jean
authors.initials: J
authors.lastname: Dumoncel
authors.forename: Pascal
authors.initials: P
authors.lastname: Baron
authors.forename: Christine
authors.initials: C
authors.lastname: Marchal-Sixou
authors.forename: José
authors.initials: J
authors.lastname: Braga
mesh_terms: D000293:Adolescent; D000366:Age Determination by Teeth; D002648:Child; D003430:Cross-Sectional Studies; D003817:Dentition; D005147:Facial Bones / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000254:growth & development*; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014070:Tooth / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000254:growth & development*