Fifty years ago this week, public health history was made in Grand Rapids, Mich.
On Jan. 25, 1945, Grand Rapids became the first city in the world to fluoridate its water. In doing so, it launched a program destined to become what dental professionals and others have called one of the most successful public health experiments ever.
"One of the most exciting experiences of my career was observing firsthand the benefits of fluoridation in the people of Grand Rapids," said Dr. David Scott, former director of the National Institute of Dental Research and one of the researchers. The study was sponsored by the Public Health Service, the University of Michigan and the city of Grand Rapids.
Results came early: After 11 years of what was a planned 15-year study of tooth decay among the city's 30,000 schoolchildren, scientists announced that the rate of cavities had plunged by 60%.
Subsequent studies have solidly confirmed fluoride's benefits.
From 1971 through the mid-1980s, three national surveys of children's oral health showed a continued decline in cavities attributed to the use of fluoride, according to the dental institute, which is part of the National Institutes of Health.
The most recent survey, taken in 1986-87, found that American children had 36% fewer cavities than they did at the beginning of the 1980s, a decline similar to one shown during the 1970s.
Today, half of the children entering first grade have never had a cavity thanks to fluoridation, according to the American Dental Assn. Moreover, fluoride also can reduce cavities by 15% to 35% in adults, the ADA said.
More than 144 million Americans in about 10,500 communities drink fluoridated water. Put another way, about 70% of U.S. cities with populations of more than 100,000 add the mineral to their water, according to the federal Centers for Disease Control and Prevention. About 26 million Americans live in areas without central water systems, such as those who drink water from private wells.
In California, the cities of Los Angeles, San Diego and San Jose do not fluoridate their water; San Francisco, Long Beach, Oakland and Fresno do.
Experts give several reasons why the number of cities participating isn't greater. These include costs and inertia on the part of some local governments--which run the water systems--to make the decision to fluoridate. Perhaps more significantly, there has been a lingering public unease in some quarters about adding anything to the community water supply.
The latter attitude has been fueled over the years by isolated anti-fluoridation drives, where opponents have attacked fluoridation as a Communist plot and a violation of civil liberties, or claimed that the substance promotes everything from cancer, birth defects and sickle cell anemia to heart disease and AIDS. Several studies in recent years have shown no evidence that fluoride poses any health risks.
Despite its critics, the practice has been endorsed by the American Dental Assn., the American Medical Assn., the World Health Organization, the American Cancer Institute, the CDC and the Public Health Service.
In recent years, fluoride also has been added to toothpaste and mouth rinse. Other sources include drinks made with fluoridated water, fluoride drops or tablets and topical application in the dentist's office.
In addition to preventing decay, water fluoridation has been shown to "remineralize," or rebuild, enamel layers in teeth at spots affected by early stages of decay, the ADA said.
Scientists are also examining other possible therapeutic uses of fluoride. A study published in the April, 1994, Annals of Internal Medicine by researchers at the Texas Southwestern Medical Center showed that a regimen of fluoride and calcium supplements appeared to prevent new spinal fractures and helped to rebuild bone loss in post-menopausal women suffering from a major form of osteoporosis.
Experts call fluoridation a real bargain.
It costs an average of 51 cents per person per year, and about $38.25 over a lifetime--less than the average cost of about $42 for one dental filling, the dental institute said. Every dollar invested in community fluoridation programs saves about $80 in dental bills, the ADA says.
Research on fluoride and its effects on tooth enamel began in the early 1930s under Dr. H. Trendley Dean, a dentist at what was then the National Institute of Health, after scientists observed low decay rates among people whose drinking water contained high levels of naturally occurring fluoride.
By the early 1940s, dental scientists concluded that water containing 1 part per million of fluoride would protect teeth from decay, and decided to test their theory by adding the mineral to the almost fluoride-free Grand Rapids water supply.
"The most important historical feature of water fluoridation was that this public health measure simply replicated what had already been demonstrated in nature," Scott said.
Exactly how fluoride prevents cavities is not fully understood, but scientists do know that fluoridated water most helps those who drink it from birth "and the protection holds throughout life for persons who continue to live in fluoridated communities," the dental institute said.