Dentistry: A Little Fluorine Is Good

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New York City is desperately short of water, but next week it will greatly improve the supply that it has. It will add just a smidgen of fluoride—one part per million parts—to the water drunk by some 9,000,000 people who live or work in and around the city. The purpose, of course, is to improve dental health by reducing cavities. Already, 50 million other Americans in 2,848 communities get the same insurance added to their water. In addition, 7.7 million Americans drink water that has already been fluoridated by quirks of nature.

Pro & Con. Many other communities are debating whether to adopt fluoridation. Though almost all doctors are convinced that the addition of a minute amount of fluorine (usually in the form of sodium fluoride) is the best way to prevent tooth decay, a large number of citizens' groups loudly oppose it, contending that fluoridation is a Communist plot to poison the nation. Amidst this fuss, two University of Rochester professors last week published a massive monograph with all the pertinent facts, pro and con, on the matter. In their 786-page Fluorine Chemistry, Volume IV (Academic Press; $28), Dr. Harold C. Hodge and Dr. Frank A. Smith compile the important evidence that has been gathered since the effects of fluoride on teeth were first observed by Dentist Frederick S. McKay in Colorado Springs 50 years ago. Their findings:

> The younger a child is when he starts getting fluoridated water, the better. If the child's mother drinks fluoridated water, the benefits begin as early as the time of conception. Some benefit will follow if he gets it at any time in childhood. And the benefit is lifelong.

> Though fluoridation does not prevent all tooth decay, it reduces the number of cavities by at least one-third and as much as two-thirds. Cavities that do occur are not so deep, nor do they enlarge so fast, as those in children who have not had fluorides.

> Overdoses of sodium fluoride can in deed be dangerous, as was tragically shown in 1943 when a mental patient dumped 17 lbs. of it into 10 gals. of eggs about to be scrambled at Oregon State Hospital. The dead: 47. Even in lesser doses, sodium fluoride can be harmful. But health officers can easily guard against overdoses, pour just the right quantity into the local water.

> The proper amount of fluoridation varies with the climate, which in turn influences the amount of water that people drink. One part per million is close to ideal for a place with an average year-round temperature about 60°F. In colder climes it can well go up to 1.2 p.p.m. (as in Joliet, Ill., with an annual average temperature of 50°); in warmer places, where people drink more it should be kept down around 0.7 p.p.m.

> Higher concentrations occurring naturally (up to 8 p.p.m. in Bartlett, Texas) have had no detectable ill effects on the growth or health of children or adults. But because they do no good, and lead to mottling of the teeth, these excess amounts should be artificially reduced. Bartlett and Britton, S. Dak. (6.7 p.p.m.) are cutting their natural levels down to about 1 p.p.m. A 150-lb. man who drinks 1-p.p.m. fluoridated water would have to drink a bathtubful, or 70 to 100 quarts daily, to get the minimum overdose that seems to affect the thyroid gland. The overdoses needed to damage kidney function or bones are still greater.