title: Dental fluorosis and dental caries in permanent teeth: rural schoolchildren in high-fluoride areas in the Shaanxi province, China.
abstract: OBJECTIVE
  To study the dental fluorosis and caries in the permanent teeth of 12 to 13-year-old children in fluorosis-endemic areas; to assess the relationship between fluorosis and the fluoride content of the drinking water and the relationship between caries and the fluoride content of the water; finally, to analyze the effect of fluoride intake and water stored in clay pots on dental fluorosis.
  
  
  METHODS
  477 children were divided into 5 groups (A to E) according to the fluoride concentration of the waters, i.e. by 0.4, 1.0, 1.8, 3.5, and 5.6 mg F/l, respectively. Dental fluorosis was assessed by TF score and caries by the DMF-T index. A questionnaire was used to obtain information about water storage and other information relevant to children's fluoride intake.
  
  
  RESULTS
  A positive relationship was found between the mean TF scores and the water fluoride concentration. In groups B and D, the TF score was higher in 13-year-olds than in 12-year-olds. Caries prevalence and mean DMF-T ranged from 2.6% and 0.03 (group E) to 22.1% and 0.38 (group A). Storage of water in clay pots seemed to increase the severity of fluorosis slightly, and to decrease the caries prevalence.
  
  
  CONCLUSIONS
  Defluoridation of drinking water, or--alternatively--the provision of low-fluoride water sources, should be given high priority in the examined Shaanxi rural areas. Fluoride concentration of drinking water should be maximum 0.6 mg/l. Storage of water in the local clay pots may increase the severity of dental fluorosis.
authors.affiliation: Faculty of Dentistry, Department of Oral Science, University of Bergen, Norway. jianping_ruan@hotmail.com
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Ruan
authors.forename: Zhuang-Qun
authors.initials: ZQ
authors.lastname: Yang
authors.forename: Zhi-Lun
authors.initials: ZL
authors.lastname: Wang
authors.forename: Anne Nordrehaug
authors.initials: AN
authors.lastname: Astrøm
authors.forename: Asgeir
authors.initials: A
authors.lastname: Bårdsen
authors.forename: Kjell
authors.initials: K
authors.lastname: Bjorvatn
mesh_terms: D000293:Adolescent; D000538:Aluminum Silicates; D002648:Child; D002681:China / Q000453:epidemiology; D000077215:Clay; D003297:Cooking and Eating Utensils; D003731:Dental Caries / Q000453:epidemiology*; D019229:Dentition, Permanent; D004812:Epidemiologic Methods; D005260:Female; D005459:Fluorides / Q000032:analysis* / Q000633:toxicity; D009050:Fluorosis, Dental / Q000453:epidemiology*; D006801:Humans; D008297:Male; D012424:Rural Population / Q000706:statistics & numerical data*; D014881:Water Supply / Q000032:analysis*
chemical_list: D000538:Aluminum Silicates; D005459:Fluorides; D000077215:Clay