Caries frequency in permanent teeth before and after discontinuation of water fluoridation in Kuopio, Finland.
The piped water of Kuopio, Finland, was fluoridated in 1959. Owing to strong opposition by different civic groups, water fluoridation was stopped at the end of 1992.


OBJECTIVE
The aim of this study was to examine the consequences of the discontinuation on dental health.


METHODS
In 1992 and 1995, independent random samples of all children aged 6, 9, 12 and 15 years were drawn from Kuopio and Jyväskylä, a nearby low fluoride town whose distribution of demographic and socio-economic characteristics was fairly similar to Kuopio's. The total number of subjects examined was 550 in 1992 and 1198 in 1995. Caries was registered clinically and radiographically by the same two calibrated dentists in both towns.


RESULTS
In 1992, the mean DMFS values were lower in the fluoridated town for the two older age groups, the percentage differences for 12- and 15-year-olds being 37% and 29%, respectively. For the two younger age groups no meaningful differences could be found. In 1995, the only difference with possible clinical significance was found in the 15-year-olds in favor of the fluoridated town (18%). In 1995, a decline in caries was seen in the two older age groups in the nonfluoridated town. In spite of discontinued water fluoridation, no indication of an increasing trend of caries could be found in Kuopio. The mean numbers of fluoride varnish and sealant applications decreased sharply in both towns between 1992 and 1995. In spite of that caries declined.


CONCLUSIONS
These findings suggest that the decline of caries has little to do with professional preventive measures performed in dental clinics.
Seppä
L
L
Institute of Dentistry, University of Oulu, Finland. liisa.seppa@oulu.fi
Kärkkäinen
S
S
Hausen
H
H
D000293:Adolescent; D002327:Cariostatic Agents / Q000008:administration & dosage; D002638:Chewing Gum; D002648:Child; D004245:DMF Index; D003731:Dental Caries / Q000453:epidemiology*; D005387:Finland / Q000453:epidemiology; D005457:Fluoridation / Q000706:statistics & numerical data*; D005459:Fluorides / Q000008:administration & dosage; D006801:Humans; D010895:Pit and Fissure Sealants; D012494:Sampling Studies; D014100:Toothpastes; D014993:Xylitol
D002327:Cariostatic Agents; D002638:Chewing Gum; D010895:Pit and Fissure Sealants; D014100:Toothpastes; D005459:Fluorides; D014993:Xylitol