We studied the correlation between caries prevalence and daily habits of schoolchidren in two rural primary schools (AGUNI and TONAKI) and one urban primary school (AKAMICHI) in Okinawa prefecture from 1982 to 1984.
The results were as follows.
1) The caries prevalence was highest in AGUNI, and lowest in TONAKI in each year.
2) AKAMICHI showed the highest values in DI-S (OHI-S) and PMA-index of anterior teeth, and TONAKI showed the lowest values.
3) By means of discriminant analysis and factor analysis, it became clear that there were the regional characteristics which correlated with the oral status of the schoolchidren. The schoolchildren of AKAMICHI whose life style was urban (they brush their teeth well, they eat between meals many times, they eat supper late and go to bed late, ……) were higher than children in the other two regions in the mean scores of DI-S and PMA-index individually. The schoolchildren of AGUNI were inferior to those in the other two regions in health concepts (for example, they take a bath fewer times, and they brush their teeth fewer times.). The schoolchildren of AGUNI also did not have regular rhythm in their daily habits. This might be one of the reasons that the oral status of schoolchildren in AGUNI was worse than those in TONAKI.
4) The means of the fluoride concentration in drinking water were 0.3 ppm (TONAKI), 0.03 ppm (AGUNI), and 0.07 ppm (AKAMICHI).
5) There were no differences among the fluoride concentrations in the enamel surface of primary teeth in the 3 regions.