title: Caries status in 16 year-olds with varying exposure to water fluoridation in Ireland.
abstract: Most of the Republic of Ireland's public water supplies have been fluoridated since the mid-1960s while Northern Ireland has never been fluoridated, apart from some small short-lived schemes in east Ulster.
  
  
  OBJECTIVE
  This study examines dental caries status in 16 year-olds in a part of Ireland straddling fluoridated and non-fluoridated water supply areas and compares two methods of assessing the effectiveness of water fluoridation. The cross-sectional survey tested differences in caries status by two methods: 1, Estimated Fluoridation Status as used previously in national and regional studies in the Republic and in the All-Island study of 2002; 2, Percentage Lifetime Exposure, a modification of a system described by Slade in 1995 and used in Australian caries research.
  
  
  METHODS
  Adolescents were selected for the study by a two-part random sampling process. Firstly, schools were selected in each area by creating three tiers based on school size, and selecting schools randomly from each tier. Then random sampling of 16-year-olds from these schools, based on a pre-set sampling fraction for each tier of schools.
  
  
  RESULTS
  With both systems of measurement, significantly lower caries levels were found in those children with the greatest exposure to fluoridated water when compared to those with the least exposure.
  
  
  CONCLUSIONS
  The survey provides further evidence of the effectiveness in reducing dental caries experience up to 16 years of age. The extra intricacies involved in using the Percentage Lifetime Exposure method did not provide much more information when compared to the simpler Estimated Fluoridation Status method.
authors.affiliation: Health Service Executive, Sligo, Republic of Ireland. joej.mullen@hse.ie
authors.forename: J
authors.initials: J
authors.lastname: Mullen
authors.forename: J
authors.initials: J
authors.lastname: McGaffin
authors.forename: N
authors.initials: N
authors.lastname: Farvardin
authors.forename: S
authors.initials: S
authors.lastname: Brightman
authors.forename: C
authors.initials: C
authors.lastname: Haire
authors.forename: R
authors.initials: R
authors.lastname: Freeman
mesh_terms: D000293:Adolescent; D002327:Cariostatic Agents / Q000032:analysis; D003430:Cross-Sectional Studies; D004245:DMF Index; D003731:Dental Caries / Q000453:epidemiology*; D003793:Dental Restoration, Permanent / Q000706:statistics & numerical data; D004781:Environmental Exposure; D005260:Female; D005457:Fluoridation / Q000706:statistics & numerical data*; D005459:Fluorides / Q000032:analysis; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D008297:Male; D009660:Northern Ireland / Q000453:epidemiology; D009790:Occupations / Q000706:statistics & numerical data; D010895:Pit and Fissure Sealants / Q000627:therapeutic use; D012111:Residence Characteristics / Q000706:statistics & numerical data; D016388:Tooth Loss / Q000453:epidemiology; D014478:Unemployment / Q000706:statistics & numerical data; D014881:Water Supply / Q000032:analysis
chemical_list: D002327:Cariostatic Agents; D010895:Pit and Fissure Sealants; D005459:Fluorides