trend toward more research in the field of dentifrices which may effectively assist in the control of dental caries.

In this country there has developed a trend to discourage the sale of sugars in the schools. In the fall of 1950, the council on dental health of the American Dental Association adopted a resolution which requested that the sale of candy, soft drinks, and other confections be discouraged in our schools. In the May 1950 issue of the Journal of the American Medical Association, the council on food and nutrition gave its reasons why carbonated beverages should not be sold on school premises. In August 1951 the National Congress of Parents and Teachers went on record as being in favor of banning the sale of candies and carbonated beverages in the schools of our Nation.

The use of fluorides, especially the fluoridation of public water supplies, is rapidly developing into a comprehensive nationwide movement. The division of Dental Public Health of the United States Public Health Service considers the promotion of controlled fluoridation its priority 1 project. This is also true of the divisions of dental health of State health departments of this country, as well as dental society groups.

The committees of workshop, public relations, and dental health of the Tennessee State Dental Association recently conducted a workshop which had as its theme, "Help Yourself to Water Fluoridation." The meeting was attended by over 100 dentists, health workers, educators, invited guests and representatives of lay and civic groups. The workshop was planned with the same objective in mind as I am sure Dr. Dummett and his committee had in arranging this symposium; namely, that all individuals interested in dental health might think together, plan together and work together toward a goal of better dental and general health.

So.

The controlled fluoridation of water is a start in the right direction. There is evidence as to the benefits to be obtained and we need to promote the procedure with the thorough and firm knowledge that, if the people of a town want fluoridation, they have it—but they must want it and they must say Since the city official is very sensitive to community spirit, it must always be realized that 1 phone call against the practice of fluoridation will cancel 20 phone calls asking for it. Those of us in the field of dental public health feel that everyone should have the facts and if they have the facts they will be for water fluoridation. We think that fluoridation will rank with the major public-health movements of all time, and we hope that everyone interested in this most worthwhile public health program will inform others and actually start what might be called a chain reaction so that, within a relatively short period of time, fluoridated water may be made available in every community where there is an approved water supply.

WATER FLUORIDATION

(Sidney B. Finn)

We have heard from Dr. Sebelius about the magnitude of the dental caries problem. As he has suggested, if there is to be a solution to this problem, it will come through prevention, and if prevention is to make progress in eliminating the vast reservoir of untreated cavities for future generations, preventive means must be applied to large segments of the population. This would be most feasible as a public health measure on a population basis. I can think of no better way of reaching the entire population equitably than through a community water supply. Water is the only commodity consumed consistently by all persons. It is highly advisable that any agent or chemical used for the purpose of reducing dental decay for the entire population should have five important requisites: (1) It must be of unquestionable value, (2) It must be relatively inexpensive, (3) it must be safe to use, (4) it must be easily utilized on a population basis, and (5) it must require little or no effort on the part of the individual benefited.

It cannot be denied that there is more than one way of reducing dental caries. Carbohydrate restriction, topical fluoride applications, rigid adherence to the rules of oral hygiene, all are capable of doing good. However, each falls short of what is desired in one or more ways. Water fluoridation or the treatment of a communal water supply with 1 part per million of fluorine, in the form of a fluoride, meets the requirements of a preventive agent more adequately than

any ever suggested. So much so, in fact, that I can have no hesitation in strongly recommending this form of dental decay prevention for every community with a supervised communal water supply. Nowhere in medicine or dentistry has a preventive agent had such a vast amount of irrefutable evidence to recommend it, and I may add, so little reliable, confirmed evidence against it. If one studies the bibliography on water fluoridation, one is immediately impressed with the vast amount of epidemiological and experimental evidence that has gone into the establishment of the fluorine-caries hypothesis. As early as 1867, Magitot suggested that fluorine was associated in some way with the integrity of the tooth.

In 1892, Sir Crichton Browne, writing in the British Medical Journal, Lancet, indicated that teeth contained more fluorine than any tissue in the body, and that fluorine was there for a reason and that the reason was to prevent dental decay. He suggested that foods rich in this element should be incorporated into the diet of children for that purpose.

From 1908 to 1916, Doctors Black and McKay thoroughly studied a pathological condition of the teeth endemic among those reared in certain limited areas of Southwestern United States. Among these individuals the teeth were poorly formed, stained, and pitted. To this disfiguring disease, they applied the term "mottled enamel." They observed that mottled enamel could be acquired only if persons resided in these areas during the period of tooth formation, and once acquired it remained for life. They further observed that people moving into these areas after their teeth were formed did not acquire this disease. They also established that the cause of mottled enamel was in some way waterborne.

In 1931, through chemical analyses of water, and through animal experiments, it was discovered that mottled enamel was caused by excessive amounts of fluorine in the drinking water supplies. In 1938, Dean and his associates reexamined these endemic areas in Southwestern United States and other areas in the Midwest where fluorosis was endemic. They determined that the severity of the fluorosis was directly proportional to the fluorine content of the water consumed. Esthetically significant, mottling occurred only in individuals consuming over 1.5 parts per million of fluorine. Their epidemiological studies further indicated that those individuals consuming water containing 1 part per million of fluorine or over had approximately 60 percent less dental caries than was found in neighboring communities where fluorine-free water was consumed. They also made the important deduction that the reduction in dental caries was not inversely proportional to the fluorine content of the water supply. As a matter of fact, there was just as great a reduction when the water contained 1 part per million of fluorine as when it contained 14 parts per million, and one did not get disfiguring fluorosis. These observations by Dean and others from different areas of the world, received additional confirmation from animal experiments and from chemical analyses of the fluorine content of sound and carious teeth. Recent studies indicate that this resistance to caries, once acquired, persists throughout lifetime. There are actually 8 million persons in the United States consuming water containing 1 part per million of fluorine or over, naturally in the water supply.

The question soon presented itself as to why couldn't fluorine be added artificially to the water supplies in areas where fluorides were deficient. In 1939, Cox, speaking before the Pennsylvania Water Works Association, first suggested artificial fluoridation. By 1945, a number of communities in the United States were fluoridating their water on a demonstration basis, for although naturally fluoridated waters reduced the incidence of dental caries, it was still to be proved that artificially fluoridated water would do the same. In 1944, the New York State Department of Health initiated the NewburghKingston study, with dental examinations of all the school children in Newburgh. It is not the intent of this paper to discuss the results of all studies published to date. This will be done by the next speaker. I would like to confine my remarks to the Newburgh study, with which I was associated since its inception.

Newburgh, N. Y. is situated on the Hudson River, 60 miles above New York City. Its water supply was fluoridated with 1.2 parts per million of fluorine as sodium fluoride, May 2, 1945. Kingston, a similar sized city, situated 30 miles above Newburgh continued to drink fluorine-free water and served as the control. Yearly dental examinations were made with mouth mirror and explorer under good light on the entire school population of over 3,000 children in each city. At the end of a 4-year period of fluoridation all 7-, 9-, and

11-year-old children were X-rayed to determine whether X-rays would confirm our clinical findings. The X-rays did confirm our clinical findings.

In the permanent teeth of the 6- to 12-year-old children, dental caries experience was reduced 32.5 percent. Among the 6-year-olds, the reduction amounted to 77.6 percent. Since about 70 percent of all tooth decay developing in the permanent teeth of children occurs in the 6-year molar, it was of interest to see if there was a reduction in dental caries there. In the 6- to 9-year-age group, 59 percent of the first permanent molars were caries-free before the study, while 77 percent were caries-free after 4 years of fluoridation. In the deciduous teeth of children 5 years of age 27.2 percent were carious prior to fluoridation. Only 10.9 percent were carious after 4 years of fluoridation. Caries activity after 4 years as indicated by salivary bacterial counts indicated less activity in these mouths.

Another part of the Newburgh-Kingston study deals with medical aspects. In the literature are many reports about the harmful effects of fluorides. Unfortunately these reports make no distinction between toxic and nontoxic doses. Those who have actually had the greatest experience with fluorides believe that in quantities of 1 part per million fluorine no deleterious effects are observed. To determine the truth about this, a complete medical study on over 600 children in Newburgh and 600 in Kingston has been undertaken on children from birth to 14 years of age. These children receive complete physical examinations which consist of height and weight measurements, examination of body organs, blood counts and hemoglobin, urinalysis, X-rays of long bones and centers of ossification, visual-acuity tests, and audiometric examinations. I can say without equivocation that after 7 years of fluoridation no difference has been observed between the children of Newburgh and Kingston. The children of Newburgh are not suffering from malnutrition, kidney damage, or any other pathology any more than the children of Kingston or any other community. As a matter of fact the children of Newburgh are healthier; they have less tooth decay.

In speaking of water fluoridation, there are several fluoride compounds available for this purpose. Among these are sodium fluoride, hydrofluoric acid, and sodium silicofluoride. For small cities and towns sodium fluoride is recommended. Because of its solubility it is readily adaptable for use in inexpensive feeding equipment and the chemical is available in moderately abundant supply. In considering the toxicity of fluorides, my remarks will be limited to a discussion of sodium fluoride. Sodium fluoride is a white crystalline salt. In commercial form, it is dyed nile green or light blue to distinguish it from other salts that are white. It is a very toxic substance, 4 or 5 grams or a tablespoon being a fatal dose. Yet in quantities of 1 part per million fluorine, it is perfectly safe to use in communal water supplies. One part per million is a very small amount. One way of visualizing this amount, is that if one drinks on the average of 2 quarts of water a day containing 1 part per million fluorine he consumes, roughly 4 milligrams of sodium fluoride. Since 4 grams or 1 tablespoonful is a lethal dose, to get this amount, one would have to consume 1,000 times the amount of water he normally drinks in a day at 1 time, or 500 gallons of water at 1 sitting, which is an impossibility. One-quarter of a gram of sodium fluoride, when swallowed at one time may produce nausea and vomiting. In terms of fluoridated water, instead of the customary 2 quarts a day, you would have to drink 125 times that much, or 63 gallons at 1 time-again an impossibility. We hear from those opposing fluoridation, that fluoridated water might produce crippling fluorosis. This is observed only in areas where the residents consume at least 20 milligrams of fluoride a day over a period of 10 to 20 years. In case of water fluoridation at 1 part per million of fluorine, instead of 2 quarts of water a day, one would have to drink at least 21⁄2 gallons of water daily over a 10- to 20-year period, which is again over 10 times the average daily water consumption. As Cox and Hodge put it, "It is impossible to imagine any set of circumstances in which the fluoride might become sufficient to bring about chronic high-grade fluorosis." In using 1 part per million of fluoride in the water supply, there may be some possibility of getting mottled enamel, if water consumption, during the formation of the teeth, was greatly increased day in and day out. However, water consumption in an area is fairly constant and it is highly doubtful whether any mottling produced would be of sufficient import to be esthetically significant since it would probably be of the very mildest type. The question is often asked whether there was danger of getting a lethal dose if the machine should become defective. Roughly 20 pounds of sodium fluoride

are required to treat each million gallons of water at the 1 part per million fluoride level. To get 4 grams at 1 time would require, not 20 pounds per million gallons water, but 10 tons per million gallons water. No machine or human could make that error for the capacity of the machine would not be that great. As a matter of fact, in discussing toxicity, there are many instances that can be cited where a chemical may be lethal in large amounts and beneficial in small amounts. Iodine, for instance, is poisonous in large quantities. Most of you have seen the "poison" label on a bottle of iodine. Yet in small quantities it is absolutely essential for the maintenance of life. Chlorine, used to kill bacteria in most of our water supplies, when used in minute proportions, was used as a poison gas in the First World War. Even common table salt, if consumed in large quantities, may produce death. Sodium fluoride is another example of a chemical, toxic in large quantities, and beneficial in small, controlled doses. How fluorides work to produce this reduction in dental caries has still not been completely settled. When consumed in the water supply during formation of the teeth it probably changes a portion of the crystalline structure of the tooth from a hydroxylapatite to a fluorapatite. We know from minerology that the fluorapatite rocks are very hard and very resistant to acid erosion. We now believe that dental caries is caused by the action of oral bacteria on sugars and carbohydrates in the mouth. The sugars are converted to acid, and the acid, initiates the carious lesion. If we can build a tooth structure resistant to these acids, then it should be resistant to tooth decay. We believe that this might be one explanation for the action of fluorine. When consumed in communal water supplies over a great number of years, even in minute quantities of 1 part per million, there may be some topical or surface action. As an analogy, it is like building a house of stucco. If you want a green house you can either include the green paint or pigment in the plaster, or you can apply the green paint to the surface after the plaster has set. By either means, the result is a green house, although the green paint incorporated in the plaster will probably last longer.

SUMMARY

In summary, may I say that there is evidence to indicate that fluorides used in communal water supplies will reduce dental caries. The reduction once acquired should persist for life. There is absolutely no reliable evidence to indicate that 1 part per million of fluorine incorporated into the communal water supply will produce deleterious effects. It is recommended that any community that has a supervised communal water supply should fluoridate its water.

BETTER DENTAL HEALTH THROUGH WATER FLUORIDATION-A PROGRESS REPORT

(Zachary M. Stadt)

INTRODUCTION

The purpose of this first Public Health Institute, as noted by Dr. Dummett, is to bring together the most promising or currently best thinking in the several fields of public health, with special emphasis on their application to the health needs of people in the rural areas.

Water fluoridation, as a proved method for the mass partial prevention of dental decay, can be applied wherever there is a community water-distribution system. Today, Norwood, Wash., with a population of 150 people, is adding fluoride to its water supply for expected dental health benefits. In time, it should be possible to assure that all water supplies, private or communal, will have beneficial fluoride concentrations.

BROAD ENDORSEMENT

The evidence demonstrating dental health benefits derived from water-borne fluorides is so overwhelmingly abundant and constantly increasing, that the measure is now endorsed by important international, national, and local groups concerned with health. Those organizations and agencies include the Interassociation Committee which is composed of the American Dental Association, the American Medical Association, the American Hospital Association, the American Nurses' Association, the American Public Health Association and the American

Public Welfare Association. Other endorsers are the Federation Dentaire Internationale, the National Research Council, the United States Public Health Service, the State and Territorial Health Officers, the State and Territorial Dental Health Directors, the American Association of Public Health Dentists, the majority of State dental societies, many State health departments, an increasing number of State medical societies, and hundreds of county dental and medical groups, boards of health, local professional organizations, and lay organizations such as the Jaycees, Rotarians, Lions, and Kiwanis.

TROWTH AND DEVELOPMENT OF FLUORIDATION

Among those who have contributed to a better understanding of the fluorinedental caries relationship are the moderator of this symposium, Dr. J. F. Volker (1) and our essayist Dr. S. B. Finn (2). From their observations and those of others (3) and (4) the adaptation of observed phenomena to practical application was but one step. On August 19, 1942, Dr. W. L. Hutton, health officer, proposed to the Brantford, Ontario, Board of Health that water fluoridation should be established for dental health benefits. The Provincial authorities refused the request (5).

In 1945, four studies were started: (a) Grand Rapids-Muskegon in Michigan; (b) Southbury-Mansfield, Conn.; (c) Newburgh-Kingston, N. Y.; and (d) Brantford-Sarnia, Ontario, Canada. The number of people involved in the 4-study areas totaled around 240,000. From 1945 to 1950 growth was slow, increasing to some 44 places in 14 States. The big spurt in 1951 followed endorsement by the United States Public Health Service, based on findings derived from their Grand Rapids, Mich., study and the endorsement by the American Dental Association.

The following comparison illustrates the rapid increase in fluoridation during the last year (the figures are not absolute): (see table I).

THREE PERCENT OF 15,000 WATER SUPPLIES HAVE FLUORIDATION IN OPERATION OR APPROVED

In his report to the State and Territorial health officers, Knutson (6) noted that (a) 93 percent of all public water supplies are in communities of 10,000 population or less, (b) that of the 16,750 public water supplies in this country

2 If we correct the totals for population increases and those on the distribution systems who are not included in the community census, we could add 5 percent, hence the April 1951 total would be 23,432,264 and the March 1952 total would be 38,651,195.

some 15,000 do not contain natural fluorides, and (c) that at the present rate of development it would take 150 years to complete the job of getting all the water supplies fluoridated.

At the present time some 200 communities are fluoridating and around 250 others have registered their approval, for a total of 450 places or 3 percent of the 15,000 communities with fluoride-deficient water supplies. If all 450 places should be in operation in the near future, they would represent a total population of some 20,000,000 people, or one-fifth of the 100,000,000 people on community water distribution systems. How long will the remaining 14,550 communities with their 80 million population continue to deprive themselves of this assured method of mass partial prevention of dental decay? It is the job of all of us here to see that the job is done in the next 5 years, not the next 150. Of course, it is a big job, but it gets easier every day.