title: Impact of dentofacial development on early mandibular incisor crowding.
abstract: BACKGROUND
  In this retrospective longitudinal study, we evaluated the influence of dentofacial development on mandibular incisor crowding from the early mixed dentition (T1) to the early permanent dentition (T2).
  
  
  METHODS
  The sample was selected from 1212 longitudinally followed untreated subjects. Cephalometric radiographs and dental casts of 42 subjects (mean age, 8.66 years) with mandibular incisor crowding were evaluated at T1 and T2. Dentoskeletal variables were compared, and their influence on crowding changes was estimated. The sample was divided regarding incisor crowding severity (≤2 mm and >2 mm) and behavior (improvement and worsening), and the variables with a significant influence on the crowding changes were compared between the groups (P <0.05).
  
  
  RESULTS
  Incisor crowding decreased from T1 to T2. The crowding changes were influenced by the amount of initial crowding, leeway space, incisor protrusion, and maxillary width increase. Crowding of 2 mm or less was not a good predictor for self-correction, with similar chances for improvement or worsening.
  
  
  CONCLUSIONS
  Incisor crowding reduction can be expected from the early mixed to the early permanent dentition. The potential for crowding reduction was associated with greater initial incisor crowding, leeway space, incisor protrusion, and maxillary width increase. A crowding threshold of 2 mm was not a valid borderline condition to define the self-correction prognosis.
authors.affiliation: Professor, Department of Orthodontics, Faculty of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil. Electronic address: sergioestelita@yahoo.com.br.
authors.forename: Sérgio Estelita
authors.initials: SE
authors.lastname: Barros
authors.affiliation: Professor, Department of Orthodontics, São Leopoldo Mandic School of Dentistry, Campinas, São Paulo, Brazil.
authors.forename: Kelly
authors.initials: K
authors.lastname: Chiqueto
authors.affiliation: Professor, Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Guilherme
authors.initials: G
authors.lastname: Janson
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003818:Dentition, Mixed; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D007180:Incisor; D008137:Longitudinal Studies; D008297:Male; D008310:Malocclusion / Q000503:physiopathology*; D008445:Maxillofacial Development; D012189:Retrospective Studies