Fluorine in the control of dental caries.

The year 1955 marks the tenth year of fluoridation in three North American cities. After extensive clinical examina­ tions of the school population, fluorida­ tion of the public water supply began early in 1945 at Grand Rapids, Mich., Newburgh, N. Y., and Brantford, On­ tario. Also in 1945, 5,116 children, 4 through 16 years of age, were examined at Aurora, 111., one of the cities which had provided outstanding evidence of the dental health value of a domestic water containing optimal amounts of fluoride. From these examinations at Aurora, den­ tal caries prevalence rates, specific for age, were computed and plotted as an “ expectancy curve,” or the level of dental caries experience which might reasonably be expected in cities with fluoridated water supplies after the passage of an adequate period of time. Today the dental caries experience rates for the 6, 7, 8, 9 and 10 year old children in the three cities mentioned closely approximate the “ expectancy curve” of Aurora recorded a decade ago. After nine years of fluoridation, the over­ all prevalence rates show a reduction of nearly 60 per cent when compared with prefluoridation dental caries experience. The results from these three cities evi­ dence the gradual transition of the theory of fluoridation into a scientific law. An increasing number of reports from nu­ merous other independent studies, nota­ bly Evanston, 111., merely augment the overwhelming mass of scientific evidence now being recorded in the literature. What was a hope of a decade ago is now a truism of preventive dentistry. The most ubiquitous of crowd diseases— den­ tal caries— has been brought under a large measure of control by means of fluoridation— a method safe, efficient and inexpensive.