Trace Elements and Caries

The influence of trace elements on the prevalence of caries is a confused subject. However, sufficient evidence has been ac-cumulated to suggest that it is a subject that justifies a continuing and expanding research effort. The conclusive demonstra-tion of the inverse relationship between caries prevalence and fluoride (F) intake at once indicates the potential effect of a trace element on caries and makes it un-necessary to deal with F in this report. If the epidemiologic studies of Arnold' are examined it can be seen that in addition to lower caries prevalence in localities with optimal levels of F in water, there were also substantial differences in caries preva-lence between localities where the F con-tents of the waters were low and of the same level. For instance, in Clarksville (Tenn) with 0.2 ppm F in the water, the mean number of DMFT in 12- to 14-year-old children was 4.58; whereas in Key West (Fla) with 0.1 ppm F in water the mean number of DMFT per child was 10.70. Several other examples of this sort appear in Arnold's ' studies. Similar examples can be cited from the classic studies of Ock-erse2 in South Africa which also show that there were large unexplained differences in caries prevalence between localities where low F waters were used. These and other substantial differences in caries prevalence between comparable populations that can-not be explained on the basis of F intake may have a variety of causes, but evidence is available that suggests that variations in the intake of trace elements other than fluoride, in food or water, may be impli-cated. This paper will consider briefly the dif-ferences that may occur in the trace ele-ment content of foods and water and the way in which these may influence trace element intake by man, the results of some investigations that indicate a potential rela-tionship between the intake of particular trace elements and the prevalence of caries in man or experimental animals, and the mechanisms by which trace elements may influence susceptibility to caries.