[Continued reduction of incidence of caries among children and young adults in USA].

The article presents data from National Institute of Health on the prevalence of dental caries in 5-17 year olds in 1986-87 in USA. The data were compared with a previous study from 1979-80. Almost 50% of the children had no caries experience in 1986-87 compared with 36% in 1979-80. The DMFS data showed a reduction of about 36%, the mean for 1979-80 and 1986-87 being 4.77 and 3.07, respectively. The survey results showed that decay on the smooth surfaces of teeth, the surfaces that benefit most from fluoride, is disappearing. Today, two-thirds of caries is found on the occlusal surfaces of teeth. In Norway, the percentage of 5-year-olds without caries experience and mean DMFT in 12- and 18-year-olds have been registered since 1984. The American data are therefore not easily comparable with the situation in Norway. However, the mean DMFS values in 18-year-olds is hardly less than 13, whereas the average DMFS value of US 17-year-olds in 1986-87 was 8.04. The NIDR survey did not address the question of what is causing the decline in dental caries. The most likely reason is the widespread use of fluoride and in particular use of fluoride dentifrices. Fluoride dentifrices were introduced on the American marked in the 1950s, and in Norway in 1971. It is speculated that a further decline in dental caries may be expected also in Norway.