title: Childhood intelligence and early tooth wear patterns.
abstract: OBJECTIVE
  The aim of this study is to explore the relationships between early dental wear patterns and preschool IQ (Intelligence Quotient, by Stanford-Binet) of the child to illuminate the historic relationship of mental queries and bruxism.
  
  
  METHODS
  The dental study participants were 864 Euro-American preschool and school children whose IQs were tested for school maturity purposes at the age of 4 years, followed by dental data in a cross-sectional manner at the mean age of 7.8 years. Worn dentitions were classified as "symmetric" or "right-" and "left-sided," based on the faceting of the teeth.
  
  
  RESULTS
  In general, the relationships of tooth wear and intelligence were scarce, reflecting social background factors. Statistically significant results between asymmetric wear and gender groups suggest that direction of jaw function has a role in the regulation of processes responsible for individual mental performance in childhood.
  
  
  CONCLUSIONS
  Increased left-side tooth wear and early advantage in the intelligence test in girls is intriguing due to the fact that they reach maturity earlier than boys in verbal articulation, controlled in most cases by the limited area on the left side of the brain.
authors.affiliation: a Department of Oral Development and Orthodontics, Unit of Oral Health Sciences , Medical Research Center, University of Oulu, Oulu University Hospital , Oulu , Finland.
authors.forename: Tuomo
authors.initials: T
authors.lastname: Heikkinen
authors.affiliation: a Department of Oral Development and Orthodontics, Unit of Oral Health Sciences , Medical Research Center, University of Oulu, Oulu University Hospital , Oulu , Finland.
authors.forename: Jaana
authors.initials: J
authors.lastname: Rusanen
authors.affiliation: b Graduate School of Dentistry , Tohoku University , Sendai , Japan.
authors.forename: Koshi
authors.initials: K
authors.lastname: Sato
authors.affiliation: a Department of Oral Development and Orthodontics, Unit of Oral Health Sciences , Medical Research Center, University of Oulu, Oulu University Hospital , Oulu , Finland.
authors.forename: Paula
authors.initials: P
authors.lastname: Pesonen
authors.affiliation: a Department of Oral Development and Orthodontics, Unit of Oral Health Sciences , Medical Research Center, University of Oulu, Oulu University Hospital , Oulu , Finland.
authors.forename: Virpi
authors.initials: V
authors.lastname: Harila
authors.affiliation: a Department of Oral Development and Orthodontics, Unit of Oral Health Sciences , Medical Research Center, University of Oulu, Oulu University Hospital , Oulu , Finland.
authors.forename: Lassi
authors.initials: L
authors.lastname: Alvesalo
mesh_terms: D002012:Bruxism / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007360:Intelligence; D008297:Male; D057085:Tooth Wear / Q000453:epidemiology*
keywords: Attrition; bimaturism; brain function; bruxism; intelligence quotient; lateralization; preschool