title: Primary dentition unilateral crossbite in relation to functional lateralities.
abstract: OBJECTIVE
  The aim of this study was to explore primary dentition unilateral crossbite malocclusion prevalences in functionally true right-sided and nonright-sided children, with the latter having 1 or more left-sided or indeterminate functions (eye, hand, foot).
  
  
  METHODS
  The transversal relationship of the primary teeth was determined from dental casts of 1,835 young African American (60%) and Caucasian (40%) children in a cross-sectional sample at a mean age of 8.5 years. Hand, foot, and eye preferences (right, left, or indeterminate) were recorded at the age of 4 years during the same collaborative perinatal study. The prevalences of left and right crossbites were compared between true right-sided and mixed or completely nonright-sided children using chi-square analysis.
  
  
  RESULTS
  Unilateral crossbite occurred in 140 cases with a complete set of laterality tests: 65 were right-sided and 75 left-sided. True right-sided children had more bilaterally symmetric occlusions and less crossbite on the right side than those having nonright-sidedness in their functions, with the differences being statistically significant (P<.01).
  
  
  CONCLUSIONS
  These results point to anatomical relationships between the structures supporting the occlusion, the asymmetric neurocranium, and the cranial base. This suggests variable unilateral compensatory growth after unbalanced fetal asymmetry, modified by sidedness and the growth-stimulating effects of early lateralized functions and oral habits.
authors.affiliation: Department of Oral Development and Orthodontics, Institute of Dentistry, University of Oulu, Finland. tpth@sun3.oulu.fi
authors.forename: Tuomo
authors.initials: T
authors.lastname: Heikkinen
authors.forename: Pertti
authors.initials: P
authors.lastname: Pirttiniemi
authors.forename: Mathias
authors.initials: M
authors.lastname: Grön
authors.forename: Lassi
authors.initials: L
authors.lastname: Alvesalo
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000473:pathology*; D014094:Tooth, Deciduous