title: [Dental caries and fluorosis among 12-year-old children with different fluoride exposure in Heilongjiang province].
abstract: OBJECTIVE
  Heilongjiang province is one of the drinking water type of the endemic fluorosis areas in China. The aim of this study is to evaluate the relationship between dental caries and dental fluorosis in 12-year-old children in Heilongjiang province and the concentration of fluoride in local drinking water.
  
  
  METHODS
  The representative samples were selected by multi-stage, stratified and random sampling including 6 different regions and 792 subjects. Clinical examinations for dental caries and dental fluorosis were based on WHO methodology. SPSS12.0 software package was used for data analysis.
  
  
  RESULTS
  The concentration of fluoride in drinking water in 6 regions was 0.29 mg/L, 0.40 mg/L, 0.68 mg/L,0.77 mg/L, 0.80 mg/L and 1.14 mg/L, respectively, the corresponding prevalence of dental caries was 44.7%, 43.2%, 41.7%, 37.1%, 28.0% and 40.5%. In the region with fluoride concentration of 0.8 mg/L, the prevalence of dental caries was the lowest, which was significantly different from other regions (P<0.05). The relationship between the concentration of fluoride in tap water and the prevalence of dental caries showed a negative correlation with the coefficient of 0.81 (except 1.14 mg/L fluoride ). There was also a positive correlation between the concentration of fluoride in tap water and the community dental fluorosis index (CFI) with a coefficient of 0.78.
  
  
  CONCLUSIONS
  The prevalence of dental caries can be lowered by adequate fluoride concentration in drinking water; However, dental caries and fluorosis would prevail when exposed to high fluoride concentration.
authors.affiliation: Heilongjiang Provincial Oral Disease Prevention Hospital, Harbin 150001, Heilongjiang Province, China.
authors.forename: Li
authors.initials: L
authors.lastname: Bao
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D002648:Child; D002681:China / Q000453:epidemiology; D003731:Dental Caries / Q000453:epidemiology*; D005459:Fluorides / Q000032:analysis; D009050:Fluorosis, Dental / Q000453:epidemiology*; D006801:Humans; D015995:Prevalence; D014881:Water Supply
chemical_list: D005459:Fluorides