Specifically, fluoridated water strengthens teeth both systemically and topically, that is, fluoride ions reach the tooth enamel from within the body and by direct external contact with teeth, while drinking for instance.
Fluoride ions work into the crystalline structure of the tooth surface and make the structure a more perfect and thus more stable crystal. The tooth is therefore less susceptible to decay by acid attack. (Tooth decay is largely caused by acid dissolution of enamel. Acid is a byproduct of food decay.)
Dr. Paul F. Depaola, head of the department of Clinical Trials and Experiments at the Forsythe Dental Research Center, says that his studies have convincingly demonstrated a definite inverse correspondence between levels of water fluorides and tooth decay. Cavity incidence drops well over 60 per cent with increasing fluoride concentrations, he found.
Optimal fluoride levels are about one ppm, which is the current Cambridge level. Some such naturally fluoridated areas in the U.S. as the Dakotas have water fluoride concentrations of up to 10 ppm.
Such extreme concentrations can produce one deleterious side effect: fluorosis. Fluorosis causes white splotches to develop on teeth, and later these splotches turn brown, and the teeth soften.
Generally, the Massachusetts health community is happy to see the system finally installed, Josephine Steinhurst, executive director of the Massachuetts Citizens Committee for Dental Health, says. Dr. James M. Dunning, professor of Ecological Dentistry Emeritus, has been interested in water fluoridation since 1942, "when evidence of natural fluoridation and reduction of cavities first hit the press," he says.
Dunning has taught dental public health for 25 years and has fought to fluoridate Boston for more than 20 of them. He was also a key advocate for Cambridge fluoridation.
Cambridge voters defeated a proposition to fluoridate the city in 1953, and then reversed their decision in a referendum in 1960. But three years later fluoridation was discontinued in another referendum. Pro-fluoridation forces finally won: the city has been fluoridating since April 1974.
President Carter, in a telegram to the American Dental Association on Oct. 7, said, "Fluoridation is safe, and...is the most effective public health measure available to improve the nation's dental health and reduce unnecessary dental expenditures."
Carter signed a mandatory statewide fluoridation bill during his term as governor of Georgia, and some fluoridation proponents are now pondering the possibilities of a similar national law.
Bock is ambivalent about the idea of a mandatory national program. "My gut reaction is 'yes,' but I'm not sure the body politic as a whole is acute enough to accept it," he says. On the other hand, Bock thinks "'no,' too. There should be no political fight on a scientific issue. The issue is already too charged with emotion and politics," he says.
Lawrence is in favor of legislating fluoridation for the state, and even the country, but doubts that such legislation will be adopted in the near future.
Meanwhile, more than half the people in this state will start this New Year fighting cavities without even resolving to "brush more often, and maybe, floss."