Water fluoridation has not been introduced in Norway, although 99% of the population receive water with suboptimal fluoride levels. Alternative methods of fluoride prophylaxis have gained wide acceptance in this country. While less than 1% of the children received fluoride tablet in 1971, sales data in 1976 indicated a daily supply of fluoride tablets to 50% of the 0-5-year-olds and to 20% of the 6-11-year-olds. Most schoolchildren have joined mass prophylactic programs with regular with regular applications of fluoride solutions. Furthermore, fluoride-containing dentifrices have become available and are increasingly used. The increased use of fluoride has been paralleled by a marked reduction in caries and restorative need. During the past 5 years, a reduction of about 45% in the number of fillings inserted in 6-17-year-old children has been noted. In some areas, a 70% reduction has been recorded. The ratio between expenses for prophylaxis and savings in cost of treatment is favorable. The Norwegian Adverse Drug Reaction Committe received 34 case reports of adverse effects ascribed to fluoride prophylaxis, from 1970 to 1977. None of the 25 follow-up studies performed, suggested fluoride to have been responsible for the reported symptoms. In Norway, the benefits of fluoride prophylaxis are becoming increasingly evident.
During routine orthodontic screening in Oslo, Norway, of 3,157 children, aged 1--11 years and born in 1963/64, 36 cases (1.14%) with cosmetically marring discoloration of permanent front teeth were registered. Thirty-four of them arrived for a more exhaustive examination, which in 24 of the children revealed positive tetracycline fluorescence on exposure to ultraviolet light. In 13 (0.4%) of the children, the discolorations were diagnosed to be tetracycline-induced. Enamel hypoplasia was frequently found in teeth with positive fluorescence. Multiple exposures to various tetracyclines were reported in all children who exhibited positive fluorescence.
About 99% of the Norwegian population are supplied with surface water with very low fluoride levels. Accordingly, they need to use fluoride preparations to prevent dental caries. Groundwater with excess fluoride is a problem mainly in a few areas of South-Eastern Norway, where in some samples of borehole water the fluoride concentration has even exceeded 10 ppm. A warning is given against the use of high-fluoride water when preparing drinks and foods for children. Infants given dried milk formulas diluted with water are at particular risk of developing fluorosis. The recommended daily meals for a three month-old child contain 900 ml water. At a level of 2 ppm, the fluoride content of this volume will exceed the upper limit of the safe and adequate intake for a child this age by 3-4 times. Water used for this purpose should preferably not contain more than 0.5 ppm fluoride. While only few Norwegians are at risk of being exposed to high-fluoride water this problem affects many persons in other parts of the world. With reference to a joint Kenyan-Norwegian research project, the paper is illustrated by cases of dental fluorosis from a Kenyan village supplied with 9 ppm fluoride water. Dental fluorosis of such severity has never been encountered in Norway.