title: Emergence of the first permanent molar in 5-6-year-old children: implications from a longitudinal analysis for occlusal caries prevention.
abstract: The timing of tooth emergence is of considerable importance in the planning of prevention of occlusal caries.
  
  
  OBJECTIVE
  The aim was to estimate the trends of emergence of the first permanent molars in girls and boys between 5-6 years of age, since more children are included in the first grade after Brazilian elementary education has been extended from eight to nine years of duration.
  
  
  METHODS
  Dental spaces of 497 children aged 60 months or older were examined four times by a calibrated dentist (kappa > 0.97) during 18 months in a longitudinal study. The first permanent molar was considered emerged when any tooth surface could be reached by a ball point probe. Participants' age was measured in months; 95% confidence intervals were obtained for prevalence and incidence values for each sex in three age groups--60.0 to 65.9; 66.0 to 71.9; 72.0 to 77.9 months. Incidence rate ratios were estimated by Poisson regression analysis.
  
  
  RESULTS
  The majority of children from 66.0 to 71.9 months and 72.0 to 77.9 months presented at least one emerged permanent molar. For each three children in the 66.0-71.9-month group, at least one had all four permanent molars emerged.
  
  
  CONCLUSIONS
  The emergence trends observed justify the need for specific protection and surveillance measures for occlusal caries prevention.
authors.affiliation: Departamento de Prática de Saúde Pública, Faculdade de Saúde Publica, Universidade de São Paulo, São Paulo. pafrazao@usp.br
authors.forename: Paulo
authors.initials: P
authors.lastname: Frazão
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003731:Dental Caries / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008963:Molar; D012737:Sex Factors; D014078:Tooth Eruption