title: Association between breastfeeding duration and mandibular retrusion: a cross-sectional study of children in the mixed dentition.
abstract: BACKGROUND
  In this study, we examined the relationships among breastfeeding duration, nonnutritive infantile sucking habits, Class II facial patterns with mandibular retrusion, and Class II dental relationships.
  
  
  METHODS
  A sample of 249 children in the mixed dentition was examined by 2 orthodontists. Data about the duration of breastfeeding and nonnutritive sucking habits were obtained by written questionnaires answered by the parents.
  
  
  RESULTS
  The chi-square test did not indicate a statistically significant association between breastfeeding duration and mandibular deficiency or Class II malocclusion. However, statistically significant associations were found between short breastfeeding duration (<6 months) and nonnutritive sucking habits, and between nonnutritive sucking habits and Class II malocclusions.
  
  
  CONCLUSIONS
  These findings point to the hypothesis that nonnutritive sucking habits may work as a dominant variable in the relationship between breastfeeding duration and the occurrence of Class II malocclusion. However, the prevention of mandibular deficiency should not be listed as one of the advantages of breastfeeding.
authors.affiliation: Department of Orthodontics, PrevOdonto Study Center, Rio de Janeiro, Brazil. cristiane.luz@terra.com.br
authors.forename: Cristiane L F
authors.initials: CL
authors.lastname: Luz
authors.forename: Daniela G
authors.initials: DG
authors.lastname: Garib
authors.forename: Rafael
authors.initials: R
authors.lastname: Arouca
mesh_terms: D001938:Brazil; D001942:Breast Feeding; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003818:Dentition, Mixed; D006801:Humans; D008312:Malocclusion, Angle Class II / Q000209:etiology*; D008334:Mandible / Q000473:pathology*; D016017:Odds Ratio; D063173:Retrognathia / Q000209:etiology*; D013391:Sucking Behavior; D013997:Time Factors