title: [Effect of drinking water change upon the dental fluorosis].
abstract: OBJECTIVE
  To assess changes in prevalence and degree of dental fluorosis in individuals born before and after the introduction of water with 1.2 mg/L fluoride instead of water with 2.0-10.0 mg/L fluoride previously used in Da Li County in China.
  
  
  METHODS
  The students (n = 291) were divided into 2 groups. The dental fluorosis was scored according to Dean's classification. The statistical analysis was performed by t-test and chi(2) tests.
  
  
  RESULTS
  The prevalence of dental fluorosis was significantly lower in the group of the students drinking water from the new well (group 1) as compared to the group of the students drinking the old water (group 2), i.e. 48.8% versus 87.2% (P < 0.01). The percentage of moderate to very severe fluorosis was 13.9% and 0 in group 1 as compared to 32.0% and 8.8% in group 2. The fluorosis community index (FCI), defined by Dean, in group 1 and 2 was medium (1.01) and marked (2.12) respectively.
  
  
  CONCLUSIONS
  The results showed that: (1) The prevalence of dental fluorosis was significantly lowered by the new source of drinking water. (2) Drinking water, even with 1.2 mg/L fluoride, may cause dental fluorosis during the period of tooth mineralization.
authors.affiliation: Department of Dental Public Health, Dental School of Xi'an Jiaotong University, Xi'an 710004, China. jianping_ruan@hotmail.com
authors.forename: Jian-ping
authors.initials: JP
authors.lastname: Ruan
authors.forename: Zhong-qi
authors.initials: ZQ
authors.lastname: Liu
authors.forename: Jian-ling
authors.initials: JL
authors.lastname: Song
authors.forename: Kjell
authors.initials: K
authors.lastname: Bjorvatn
authors.forename: Mei-sheng
authors.initials: MS
authors.lastname: Ruan
mesh_terms: D000293:Adolescent; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D005459:Fluorides / Q000032:analysis*; D009050:Fluorosis, Dental / Q000453:epidemiology*; D006801:Humans; D008297:Male; D015995:Prevalence; D012737:Sex Factors; D014881:Water Supply / Q000032:analysis*
chemical_list: D005459:Fluorides