The dental ages of 149 children born and grown up in a district with naturally occurring fluoride in the drinking water (maximum level 2.0 mg/l) were compared with those of 181 control children born and grown up in a neighbouring low-fluoride district (less than or equal to 0.1 mg/l). The children were 9--12 years old. In neither group did the dental ages prove to differ from normality. It is concluded that concentrations below the highest recommended level fluoride occurring naturally in the drinking water do not seem to have any long-term effect on the individual physiologic maturation, as judged from the dental age of the growing child.

Fluoride, Mineralisation defects of the enamel, and tooth width. Acta Paediat Scand, 63: 188, 1974.-The purpose of the investigation was to appraise the frequency of enamel mineralisation defects in 151 children, aged 8-11 years, born and raised in a district in Vasterbotten county in northern Sweden, where the fluoride content of the drinking water ranges up to 2 mg/l, and to examine the mesiodistal widths of the teeth for effects of fluoride in these concentrations. The control group consisted of 213 children who had always lived in a town where the fluoride content of the drinking water was SO.1 mg/l. The mineralisation defects were recorded clinically and photographically. Owing to the various ages of the children, only mineralisation defects in permanent incisors and six-year molars were noted. The mesio-distal widths of the teeth were measured on plaster casts. The frequency of enamel fluorosis was high (34%) in those children whose drinking water had a fluoride content of 1.k2.0 mg/l and also high (31%) in th& children living in areas with a fluoride content of 1.kl.2 mg/l. No satisfactory explanation can be offered for the relatively high frequency of fluorosis. There are, however, variations in the natural fluoride concentration of the ground water and probably also considerable individual variation in water consumption. This stresses the necessity of further investigation of children's fluoride intake. No significant differences in mesio-distal widths of individual teeth could be demonstrated.