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NIDR Dentists examined these grand rapids shcoolchildren once a year to document the effects of fluoridation
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It started as an observation, that soon took the shape of an idea. It ended, five decades later, as a scientific revolution that shot dentistry into the forefront of preventive medicine. This is the story of how dental science discovered-and ultimately proved to the world-that fluoride, a mineral found in rocks and soil, prevents tooth decay. Although dental caries remains a public health worry, it is no longer the unbridled problem it once was, thanks to fluoride. |
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A Mysterious Disorder |
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In 1909 Dr. McKay (r) persuaded the Colorado State Dental Association to invite Dr. Green Vardiman Black (l), one of the nation's most eminent dental researchers, to attend 1909 convention where McKay's findings were to be presented. The two men began joint research and discovered other areas of the country where brown staining of teeth occurred. |
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Fluoride research had its beginnings in 1901, when a young dental school graduate named Frederick McKay left the East Coast to open a dental practice in Colorado Springs, Colorado. When he arrived, McKay was astounded to find scores of Colorado Springs natives with grotesque brown stains on their teeth. So severe could these permanent stains be, in fact, sometimes entire teeth were splotched the color of chocolate candy. McKay searched in vain for information on this bizarre disorder. He found no mention of the brown-stained teeth in any of the dental literature of the day. Local residents blamed the problem on any number of strange factors, such as eating too much pork, consuming inferior milk, and drinking calcium-rich water. Thus, McKay took up the gauntlet and initiated research into the disorder himself. His first epidemiological investigations were scuttled by a lack of interest among most area dentists. But McKay persevered and ultimately interested local practitioners in the problem, which was known as Colorado Brown Stain. |
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A Fruitful Collaboration |
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McKay's first big break came in 1909, when renowned dental researcher Dr. G.V. Black agreed to come to Colorado Springs and collaborate with him on the mysterious ailment. Black, who had previously scoffed that it was impossible such a disorder could go unreported in the dental literature, was lured West shortly after the Colorado Springs Dental Society conducted a study showing that almost 90 percent of the city's locally born children had signs of the brown stains. When Black arrived in the city, he too was shocked by the prevalence of Colorado Brown Stain in the mouths of native-born residents. He would write later:
"I spent considerable time walking on the streets, noticing the children in their play, attracting their attention and talking with them about their games, etc., for the purpose of studying the general effect of the deformity. I found it prominent in every group of children. One does not have to search for it, for it is continually forcing itself on the attention of the stranger by its persistent prominence. This is much more than a deformity of childhood. If it were only that, it would be of less consequence, but it is a deformity for life." |
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Black investigated fluorosis for six years, until his death in 1915. During that period, he and McKay made two crucial discoveries. First, they showed that mottled enamel (as Black referred to the condition) resulted from developmental imperfections in children's teeth. This finding meant that city residents whose permanent teeth had calcified without developing the stains did not risk having their teeth turn brown; young children waiting for their secondary set of teeth to erupt, however, were at high risk. Second, they found that teeth afflicted by Colorado Brown Stain were surprisingly and inexplicably resistant to decay. The two researchers were still a long way from determining the cause of Colorado Brown Stain, but McKay had a theory tucked away in the back of his head. Maybe there was, as some local residents suggested, an ingredient in the water supply that mottled the teeth? Black was skeptical; McKay, though, was intrigued by this theory's prospects. |
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The water-causation theory got a gigantic boost in 1923. That year, McKay trekked across the Rocky Mountains to Oakley, Idaho to meet with parents who had noticed peculiar brown stains on their children's teeth. The parents told McKay that the stains began appearing shortly after Oakley constructed a communal water pipeline to a warm spring five miles away. McKay analyzed the water, but found nothing suspicious in it. Nonetheless, he advised town leaders to abandon the pipeline altogether and use another nearby spring as a water source. |
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McKay's advice did the trick. Within a few years, the younger children of Oakley were sprouting healthy secondary teeth without any mottling. McKay now had his confirmation, but he still had no idea what could be wrong with the water in Oakley, Colorado Springs, and other afflicted areas. The answer came when McKay and Dr. Grover Kempf of the United States Public Health Service (PHS) traveled to Bauxite, Arkansas-a company town owned by the Aluminum Company of America-to investigate reports of the familiar brown stains. The two discovered something very interesting: namely, the mottled enamel disorder was prevalent among the children of Bauxite, but nonexistent in another town only five miles away. Again, McKay analyzed the Bauxite water supply. Again, the analysis provided no clues. But the researchers' work was not done in vain.
McKay and Kempf published a report on their findings that reached the desk of ALCOA's chief chemist, H. V. Churchill, at company headquarters in Pennsylvania. Churchill, who had spent the past few years refuting claims that aluminum cookware was poisonous, worried that this report might provide fresh fodder for ALCOA's detractors. Thus, he decided to conduct his own test of the water in Bauxite-but this time using photospectrographic analysis, a more sophisticated technology than that used by McKay. Churchill asked an assistant to assay the Bauxite water sample. After several days, the assistant reported a surprising piece of news: the town's water had high levels of fluoride. Churchill was incredulous. "Whoever heard of fluorides in water," he bellowed at his assistant. "You have contaminated the sample. Rush another specimen."
Shortly thereafter, a new specimen arrived in the laboratory. Churchill's assistant conducted another assay on the Bauxite water. The result? Photospectrographic analysis, again, showed that the town's water had high levels of fluoride tainting it. This second and selfsame finding prompted Churchill to sit down at his typewriter in January, 1931, and compose a five-page letter to McKay on this new revelation. In the letter, he advised McKay to collect water samples from other towns "where the peculiar dental trouble has been experienced... We trust that we have awakened your interest in this subject and that we may cooperate in an attempt to discover what part 'fluorine' may play in the matter."
McKay collected the samples. And, within months, he had the answer and denouement to his 30-year quest: high levels of water-borne fluoride indeed caused the discoloration of tooth enamel. |
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New Questions Emerge |
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Hence, from the curious findings of Churchill's lab assistant, the mystery of the brown stained teeth was cracked. But one mystery often ripples into many others. And shortly after this discovery, PHS scientists started investigating a slew of new and provocative questions about water-borne fluoride. With these PHS investigations, research on fluoride and its effects on tooth enamel began in earnest. The architect of these first fluoride studies was Dr. H. Trendley Dean, head of the Dental Hygiene Unit at the National Institute of Health (NIH). Dean began investigating the epidemiology of fluorosis in 1931. One of his primary research concerns was determining how high fluoride levels could be in drinking water before fluorosis occurred. To determine this, Dean enlisted the help of Dr. Elias Elvove, a senior chemist at the NIH. Dean gave Elvove the hardscrabble task of developing a more accurate method to measure fluoride levels in drinking water. Elvove labored long and hard in his laboratory, and within two years he reported back to Dean with success. He had developed a state-of-the-art method to measure fluoride levels in water with an accuracy of 0.1 parts per million (ppm). With this new method in tow, Dean and his staff set out across the country to compare fluoride levels in drinking water. By the late 1930s, he and his staff had made a critical discovery. Namely, fluoride levels of up to 1.0 ppm in drinking water did not cause enamel fluorosis in most people and only mild enamel fluorosis in a small percentage of people. |
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Proof That Fluoride Prevents Caries |
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This finding sent Dean's thoughts spiraling in a new direction. He recalled from reading McKay's and Black's studies on fluorosis that mottled tooth enamel is unusually resistant to decay. Dean wondered whether adding fluoride to drinking water at physically and cosmetically safe levels would help fight tooth decay. This hypothesis, Dean told his colleagues, would need to be tested.In 1944, Dean got his wish. That year, the City Commission of Grand Rapids, Michigan-after numerous discussions with researchers from the PHS, the Michigan Department of Health, and other public health organizations-voted to add fluoride to its public water supply the following year. In 1945, Grand Rapids became the first city in the world to fluoridate its drinking water.The Grand Rapids water fluoridation study was originally sponsored by the U.S. Surgeon General, but was taken over by the NIDR shortly after the Institute's inception in 1948. During the 15-year project, researchers monitored the rate of tooth decay among Grand Rapids' almost 30,000 schoolchildren. After just 11 years, Dean- who was now director of the NIDR-announced an amazing finding. The caries rate among Grand Rapids children born after fluoride was added to the water supply dropped more than 60 percent. This finding, considering the thousands of participants in the study, amounted to a giant scientific breakthrough that promised to revolutionize dental care, making tooth decay for the first time in history a preventable disease for most people. |
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A Lasting Achievement |
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Almost 30 years after the conclusion of the Grand Rapids fluoridation study, fluoride continues to be dental science's main weapon in the battle against tooth decay. Today, just about every toothpaste on the market contains fluoride as its active ingredient; water fluoridation projects currently benefit over 200 million Americans, and 13 million schoolchildren now participate in school-based fluoride mouth rinse programs. As the figures indicate, McKay, Dean, and the others helped to transform dentistry into a prevention-oriented profession. Their drive, in the face of overwhelming adversity, is no less than a remarkable feat of science-an achievement ranking with the other great preventive health measures of our century. |
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Since community water fluoridation began in 1945, it has been demonstrated to be a safe and cost-effective way to prevent tooth decay. It has been identified by the Centers for Disease Control and Prevention as one of 10 great public health achievements of the 20th century.
Water fluoridation protects teeth in two ways: |
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When delivered through the water supply to children during the tooth forming years. |
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Through direct contact with teeth throughout life. |
Hundreds of millions of Americans now receive fluoride through their community water. |
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U.S. Overall Community Water Fluoridation Status |
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Community Water Fluoridation Status by State |
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Growth of Community Water Fluoridation (1940 to 2002) |
The following sites contain additional information about community water fluoridation: |
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Surgeon General’s Statement on Water Fluoridation |
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The Story of Fluoridation |
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Fluoride Information |
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Fluoridated Water: Questions and Answers |
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Key Points |
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Fluoride prevents and can even reverse tooth decay (see Question 3). |
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More than 60 percent of the U.S. population on public water supply systems has access to water fluoridated at approximately 1 part fluoride per million parts water—the optimal level for preventing tooth decay (see Question 4).
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Many studies, in both humans and animals, have shown no association between fluoridated water and risk for cancer (see Question 5). |
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What is fluoride? |
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Fluoride is the name given to a group of compounds that are composed of the naturally occurring element fluorine and one or more other elements. Fluorides are present naturally in water and soil. |
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What is fluoridated water? |
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Virtually all water contains some amount of fluoride. Water fluoridation is the process of adding fluoride to the water supply so that the level reaches approximately 1 part fluoride per million parts water (ppm) or 1 milligram fluoride per liter of water (mg/L); this is the optimal level for preventing tooth decay (1). |
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Why fluoridate water? |
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In the early 1940s, scientists discovered that people who lived where drinking water supplies had naturally occurring fluoride levels of approximately 1.0 ppm had fewer dental caries (cavities). Many more recent studies have supported this finding (1).
Fluoride can prevent and even reverse tooth decay by enhancing remineralization, the process by which fluoride “rebuilds” tooth enamel that is beginning to decay (1, 2). |
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When did water fluoridation begin in the U.S.? |
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In 1945, Grand Rapids, Michigan, adjusted the fluoride content of its water supply to 1.0 ppm and thus became the first city to implement community water fluoridation. By 1992, more than 60 percent of the U.S. population served by public water systems had access to water fluoridated at approximately 1.0 ppm, the optimal level to prevent tooth decay (2).
The Centers for Disease Control and Prevention (CDC) considers fluoridation of water one of the greatest achievements in public health in the 20th century. |
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Can fluoridated water cause cancer? |
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The possible relationship between fluoridated water and cancer has been debated at length. The debate resurfaced in 1990 when a study by the National Toxicology Program, part of the National Institute of Environmental Health Sciences, showed an increased number of osteosarcomas (bone tumors) in male rats given water high in fluoride for 2 years (3). However, other studies in humans and in animals have not shown an association between fluoridated water and cancer (4).
In a February 1991 Public Health Service (PHS) report, the agency said it found no evidence of an association between fluoride and cancer in humans. The report, based on a review of more than 50 human epidemiological (population) studies produced over the past 40 years, concluded that optimal fluoridation of drinking water “does not pose a detectable cancer risk to humans” as evidenced by extensive human epidemiological data reported to date (4).
In one of the studies reviewed for the PHS report, scientists at the National Cancer Institute evaluated the relationship between the fluoridation of drinking water and the number of deaths due to cancer in the United States during a 36-year period, and the relationship between water fluoridation and number of new cases of cancer during a 15-year period. After examining more than 2.2 million cancer death records and 125,000 cancer case records in counties using fluoridated water, the researchers found no indication of increased cancer risk associated with fluoridated drinking water (5).
In 1993, the Subcommittee on Health Effects of Ingested Fluoride of the National Research Council, part of the National Academy of Sciences, conducted an extensive literature review concerning the association between fluoridated drinking water and increased cancer risk. The review included data from more than 50 human epidemiological studies and six animal studies. The Subcommittee concluded that none of the data demonstrated an association between fluoridated drinking water and cancer (5). A 1999 report by the CDC supported these findings. The report concluded that studies to date have produced “no credible evidence” of an association between fluoridated drinking water and an increased risk for cancer (2). |
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Where can people find additional information on fluoridated water? |
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The CDC Web site has information on standards for and surveillance of current fluoridated water supplies in the United States. Visit http://www.cdc.gov and search for “fluoridation.”
The Environmental Protection Agency (EPA) Web site has more information about drinking water and health. It includes information about drinking water quality and standards. This Web site is located at http://www.epa.gov/safewater/ on the Internet. |
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Centers for Disease Control and Prevention. Public Health Service report on fluoride benefits and risks. Journal of the Americal Medical Association 1991; 266(8):1061–1067. M/li>
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Centers for Disease Control and Prevention. Achievements in public health, 1900–1999: Fluoridation of drinking water to prevent dental caries. Morbidity and Mortality Weekly Report 1999; 48(41):933–940.
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Bucher JR, Hejtmancik MR, Toft JD, et al. Results and conclusions of the National Toxicology Program’s rodent carcinogenicity studies with sodium fluoride. International Journal of Cancer 1991; 48(5):733–737.
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Committee to Coordinate Environmental Health and Related Programs. Review of Fluoride Benefits and Risks: Report of the Ad Hoc Subcommittee on Fluoride. Public Health Service, Department of Health and Human Services, 1991.
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National Research Council. Carcinogenicity of flouride. In: Subcommittee on Health Effects of Ingested Fluoride, editor. Health Effects of Ingested Fluoride. Washington DC: National Academy Press, 1993.
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U.S. Overall Community Water Fluoridation Status |
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Community water fluoridation began in the 1940s. Since then the number of community water systems and the number of people served by fluoridated systems have been steadily increasing. Currently about two-thirds of the US population receives fluoride through their community water system. This has been an important factor in the steady decrease in tooth decay rates. |
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Table 1: Community Water Fluoridation Status, United States overall |
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Total U.S. Population |
281,421,906 |
U.S. Population on Public Water Supply Systems |
253,104,805 |
U.S. Population Not Served by Public Water Supply Systems |
28,317,101 |
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Total U.S. Population on Fluoridated Drinking Water Systems |
170,321,020 |
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Percentage of U.S. Population Receiving Fluoridated Water
(170.3 million divided by 281.4 million) |
60.5% |
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Percentage of Total U.S. Population on Public Water
Supply Systems Receiving Fluoridated Water
(170.3 million divided by 246.1 million) |
67.3% |
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Source: Centers for Disease Control and Prevention 2002 Water Fluoridation Reporting System (WFRS) |
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Community Water Fluoridation Status by State |
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Community water fluoridation began in the 1940s. Since then the number of community water systems and the number of people served by fluoridated systems have been steadily increasing. Currently about two-thirds of the U.S. population receives fluoride through their community water system. This has been an important factor in the steady decrease in tooth decay rates. |
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Table 1: Water Fluoridation status by state |
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Table 1: Percent of Population Receiving Fluoridated Water |
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Ranked by State |
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Location |
Percent |
State Rank |
United States |
65.8 |
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DC |
100.0 |
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Kentucky |
99.6 |
1 |
Illinois |
99.1 |
2 |
Minnesota |
98.4 |
3 |
Tennessee |
96.0 |
4 |
North Dakota |
95.6 |
5 |
Indiana |
95.5 |
6 |
Virginia |
93.8 |
7 |
Maryland |
93.7 |
8 |
Georgia |
93.0 |
9 |
West Virginia |
91.5 |
10 |
South Carolina |
91.4 |
11 |
Iowa |
91.3 |
11 |
Ohio |
90.6 |
13 |
Wisconsin |
89.4 |
14 |
Rhode Island |
89.2 |
15 |
Connecticut |
87.6 |
16 |
Michigan |
86.2 |
17 |
North Carolina |
84.6 |
18 |
Alabama |
82.0 |
19 |
Delaware |
80.9 |
20 |
Missouri |
80.9 |
21 |
South Dakota |
78.0 |
22 |
New Mexico |
76.6 |
23 |
Colorado |
75.4 |
24 |
Oklahoma |
74.6 |
25 |
Maine |
74.4 |
26 |
New York |
72.9 |
27 |
Nebraska |
69.5 |
28 |
Nevada |
69.4 |
29 |
Florida |
67.4 |
30 |
Texas |
65.7 |
31 |
Arkansas |
62.1 |
32 |
Kansas |
62.1 |
33 |
Massachusetts |
60.7 |
34 |
Washington |
58.9 |
35 |
Alaska |
57.3 |
36 |
Vermont |
55.7 |
37 |
Arizona |
55.4 |
38 |
Pennsylvania |
54.0 |
38 |
Idaho |
47.5 |
40 |
Mississippi |
46.1 |
41 |
Louisiana |
45.9 |
42 |
New Hampshire |
42.7 |
43 |
Wyoming |
36.7 |
44 |
California |
27.6 |
45 |
Montana |
23.8 |
46 |
New Jersey |
20.8 |
47 |
Oregon |
19.4 |
48 |
Hawaii |
8.6 |
49 |
Utah |
2.2 |
50 |
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Alphabetical by State |
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Location |
Percent |
State Rank |
United States |
65.8 |
|
Alabama |
82.0 |
19 |
Alaska |
57.3 |
36 |
Arizona |
55.4 |
38 |
Arkansas |
62.1 |
32 |
California |
27.6 |
45 |
Colorado |
75.4 |
24 |
Connecticut |
87.6 |
16 |
DC |
100.0 |
|
Delaware |
80.9 |
20 |
Florida |
67.4 |
30 |
Georgia |
93.0 |
9 |
Hawaii |
8.6 |
49 |
Idaho |
47.5 |
40 |
Illinois |
99.1 |
2 |
Indiana |
95.5 |
6 |
Iowa |
91.3 |
11 |
Kansas |
62.1 |
33 |
Kentucky |
99.6 |
1 |
Louisiana |
45.9 |
42 |
Maine |
74.4 |
26 |
Maryland |
93.7 |
8 |
Massachusetts |
60.7 |
34 |
Michigan |
86.2 |
17 |
Minnesota |
98.4 |
3 |
Mississippi |
46.1 |
41 |
Missouri |
80.9 |
21 |
Montana |
23.8 |
46 |
Nebraska |
69.5 |
28 |
Nevada |
69.4 |
29 |
New Hampshire |
42.7 |
43 |
New Jersey |
20.8 |
47 |
New Mexico |
76.6 |
23 |
New York |
72.9 |
27 |
North Carolina |
84.6 |
18 |
North Dakota |
95.6 |
5 |
Ohio |
90.6 |
13 |
Oklahoma |
74.6 |
25 |
Oregon |
19.4 |
48 |
Pennsylvania |
54.0 |
38 |
Rhode Island |
89.2 |
15 |
South Carolina |
91.4 |
11 |
South Dakota |
78.0 |
22 |
Tennessee |
96.0 |
4 |
Texas |
65.7 |
31 |
Utah |
2.2 |
50 |
Vermont |
55.7 |
37 |
Virginia |
93.8 |
7 |
Washington |
58.9 |
35 |
West Virginia |
91.5 |
10 |
Wisconsin |
89.4 |
14 |
Wyoming |
36.7 |
44 |
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Source: Centers for Disease Control and Prevention 2002 Water Fluoridation Reporting System (WFRS) |
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Growth of Community Water Fluoridation (1940 to 2002) |
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Community water fluoridation began in the 1940s. Since then the number of community water systems and the number of people served by fluoridated systems have been steadily increasing. Currently about two-thirds of the US population receives fluoride through their community water system. This has been an important factor in the steady decrease in tooth decay rates. |
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Table 1: Community Fluoridation Growth, by Population, United States 1940–2002 |
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Year |
Receiving Fluoridated Water |
Served by Community Water Systems |
Total U.S. Population |
Percentage of U.S. population receiving fluoridated water* |
Percentage of population served by community water systems receiving fluoridated water |
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Natural |
Adjusted |
Total |
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2002 |
|
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170,321,020 |
253,104,805 |
288,600,000 |
59 |
87.7 |
2000 |
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162,067,341 |
246,120,616 |
282,434,000 |
57.4 |
87.1 |
1992 |
10,011,861 |
134,657,132 |
144,217,476 |
232,438,000 |
256,894,000 |
56.1 |
90.5 |
1990 |
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250,132,000 |
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1989 |
|
|
135,256,757 |
220,179,000 |
247,342,000 |
54.7 |
89 |
1988 |
|
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132,422,064 |
218,924,000 |
245,021,000 |
54 |
89.3 |
1985 |
|
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130,172,334 |
211,730,873 |
238,466,000 |
54.6 |
88.8 |
1980 |
|
|
115,948,946 |
|
227,726,000 |
50.9 |
|
1975 |
|
|
105,338,343 |
|
215,973,000 |
48.8 |
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1970 |
|
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|
205,052,000 |
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1969 |
8,378,824 |
80,096,860 |
88,475,684 |
|
202,677,000 |
43.7 |
|
1967 |
10,009,000 |
71,916,700 |
81,925,700 |
|
198,712,000 |
41.2 |
|
1964 |
7,706,000 |
48,363,100 |
56,069,100 |
150,277,000 |
191,889,000 |
29.2 |
78.3 |
1963 |
|
46,678,380 |
|
|
189,242,000 |
24.7 |
|
1962 |
|
44,045,392 |
|
|
186,538,000 |
23.6 |
|
1961 |
|
42,201,115 |
|
|
183,691,000 |
23 |
|
1960 |
|
41,179,694 |
|
|
180,671,000 |
22.8 |
|
1959 |
|
39,628,377 |
|
|
177,830,000 |
22.3 |
|
1958 |
|
38,461,589 |
|
|
174,882,000 |
22 |
|
1957 |
|
36,215,208 |
|
|
171,984,000 |
21.1 |
|
1956 |
|
33,905,474 |
|
|
168,903,000 |
20.1 |
|
1955 |
|
26,278,820 |
|
|
165,931,000 |
15.8 |
|
1954 |
|
22,336,884 |
|
|
163,026,000 |
13.7 |
|
1953 |
|
17,666,339 |
|
|
160,184,000 |
11 |
|
1952 |
|
13,875,005 |
|
|
157,553,000 |
8.8 |
|
1951 |
|
5,079,321 |
|
|
154,878,000 |
3.3 |
|
1950 |
|
1,578,578 |
|
|
152,271,000 |
|
|
1949 |
|
1,062,779 |
|
|
149,188,000 |
|
|
1948 |
|
581,683 |
|
|
146,631,000 |
|
|
1947 |
|
458,748 |
|
|
144,126,000 |
|
|
1946 |
|
332,467 |
|
|
141,389,000 |
|
|
1945 |
|
231,920 |
|
|
139,928,000 |
|
|
1940 |
|
|
|
|
132,122,000 |
|
|
|
|
| |
|
|
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Source: Centers for Disease Control and Prevention 2002 Water Fluoridation Reporting System (WFRS) |
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© Copyrights 2009 California Dental Insurance All Rights reserved |
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