No abstract

The Inhibition of Dental Caries by Fluorine By ROBERT WEAVER, M.D., F.D.S. AINSWORTH (1933) described the appearance of teeth observed by him in the Maldon district of Essex, where the water contains about five parts per million of fluorine. For many years previously there had been much speculation, particularly in America, as to the cause of mottled enamel. Many people suspected that the mottling was produced by some substance in the drinking water, though it is of interest to note that one writer in 1926 suggested that it might be caused by a deficiency of fluorine in water. However, about two years prior to the publication of Ainsworth's paper, it was conclusively proved that endemic mottled enamel was caused by the presence of a substantial amount of fluorine in drinking water, and Ainsworth showed that this state of affairs existed in the Maldon area. He observed that the incidence of dental caries was distinctly low in the children whom he examined, but his reference to that point takes up only about four lines in an article of seventeen pages. This is not surprising. It was not then realized that very much lower concentrations of fluorine could inhibit caries, and the readers of Ainsworth's paper, looking at the really admirable accompanying pictures of Maldon teeth, might well have said to themselves: "If this is the price which has to be paid for a lowered caries incidence, then the price is much too high." I understand that this is the view taken by quite a number of residents in the Maldon district, and that it is not unusual for young people in that area to demand that perfectly sound anterior teeth be extracted because they are so unsightly. During the five years or so preceding the outbreak of World WarII, there was ain accumulation of evidence indicating that inhibition of caries could be produced by concentrations of fluorine which were too low to cause the unsightly appearance observed in teeth at Maldon and elsewhere. The person who, more than anyone else, deserves the credit for this work is Trendley Dean of the United States Public Health Service. In 1938 he showed the inverse relationship which exists between endemic dental fluorosis and dental caries prevalence, and during the next few years he, in collaboration with various colleagues, published a long series of papers which left no room for any reasonable doubt as to the caries-inhibitory effect of fluorine. When in 1944 I referred to the low incidence of caries in certain northeast Durham areas as being due to a factor F, which was probably fluorine, I did not seriously doubt Dean's conclusions; I was merely being ultra-cautious.