Water fluoridation

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Water fluoridation is the practice of adding fluoride compounds to water with the intended purpose of reducing tooth decay in the general population. Fluoride compounds are found naturally in the ground water in some regions but not in others. Fluoridation chemicals are typically added to potable water in the form of sodium hexafluorosilicate or hexafluorosilicic acid (also known as hydrofluorosilic acid). [1][2]

Fluorides such as sodium fluoride (NaF), sodium monofluorophosphate ("SMFP" or "MFP", Na2FPO3), tin(II) fluoride ("Stannous fluoride", SnF2), and amine fluorides are common ingredients in toothpaste.

History

While the use of fluorides for prevention of dental caries was discussed in the 19th century in Europe,[3] community water fluoridation in the United States owes its origin in part to the research of Dr. Frederick McKay, who pressed the dental community for an investigation into what was then known as "Colorado brown stain."[4] The condition, now known as dental fluorosis, when in its severe form is characterized by cracking and pitting of the teeth. [1] [2] [3][4] In 1909, of the 2,945 children seen by Dr. McKay, 87.5% had some degree of stain or mottling. All the affected children were from the Pikes Peak region. Despite having a negative impact on the physical appearance of their teeth, the children with stained or mottled teeth also had fewer cavities[citation needed] than other children. McKay brought the problem to the attention of Dr. G.V. Black, and Black's interest into the Colorado stain led to greater interest throughout the dental profession.

Photograph of Dr. G.V. Black (left) and Drs. Isaac Burton and F. Y. Wilson, 1909, studying the "Colorado Brown Stain" (picture taken by McKay, printed in Douglas W.A.:"History of dentistry in Colorado, 1859-1959").

Initial hypotheses for the staining included poor nutrition, overconsumption of pork or milk, radium exposure, childhood diseases, or a calcium deficiency in the local drinking water.[4] In 1931, researchers from the Aluminum Company of America (ALCOA) finally concluded that the cause of the Colorado stain was a high concentration of fluoride ions in the region's drinking water (ranging from 2 to 13.7 ppm) and areas with lower concentrations had no staining (1 ppm or less).[5] Pikes Peak's rock formations contained the mineral cryolite, one of whose constituents is fluorine. As the rain and snow fell, the resulting runoff water dissolved fluoride which made its way into the water supply.

Dental research then moved toward determining a safe level for fluoride in water supplies. The research had two goals: (1) to warn communities with a high concentration of fluoride of the danger, initiating a reduction of the fluoride levels in order to reduce incidences of fluorosis, and (2) to encourage communities with a low concentration of fluoride in drinking water to increase the fluoride levels in order to help prevent tooth decay.

The classic epidemiological study to attempt to determine the optimal level of fluoride in water was led by Dr. H. Trendley Dean, a dental officer of the U.S. Public Health Service, in 1934.[6][7] His research on the fluoride - dental caries relationship, published in 1942, included 7,000 children from 21 cities in Colorado, Illinois, Indiana, and Ohio. The study concluded that the optimal level of fluoride which minimized the risk of severe fluorosis but had positive benefits for tooth decay was 1 part per million (ppm). In 1939, Dr. Gerald J. Cox[8] conducted laboratory tests on fluoride and suggested adding fluoride to drinking water (or other media such as milk or bottled water) in order to improve oral health.[9] In 1937, dentists Henry Klein and Carroll E. Palmer had considered the possibility of fluoridation to prevent cavities after their evaluation of data gathered by a Public Health Service team at dental examinations of Native American children.[10] In a series of papers published afterwards (1937-1941), yet disregarded by his colleagues within the U.S.P.H.S., Klein summarized his findings on tooth development in children and related problems in epidemiological investigations on caries prevalence.

In the mid 1940s, four widely-cited studies were conducted. The researchers investigated cities that had both fluoridated and unfluoridated water. The first pair was Muskegon, Michigan and Grand Rapids, Michigan, making Grand Rapids the first community in the world to modify its fluoride levels in drinking water to benefit dental health on January 25, 1945.[11] Kingston, New York was paired with Newburgh, New York.[12] Oak Park, Illinois was paired with Evanston, Illinois. Sarnia, Ontario was paired with Brantford, Ontario, Canada.[13] The research found a decrease in the incidence of tooth decay in cities which had added fluoride to water supplies. However, tooth decay was declining in similar rates in non-fluoridated cities.[14] These studies would later be criticized as, "primitive," with a, "virtual absence of quantitative, statistical methods...nonrandom method of selecting data and...high sensitivity of the results to the way in which the study populations were grouped..." in the journal Nature.[15]

Effects

Where not found in the environment, fluoridation reduces tooth decay, with its associated health problems, at a low cost.[16] The United States Centers for Disease Control states, "Community water fluoridation is safe and effective in preventing tooth decay, and has been identified by CDC as one of 10 great public health achievements of the 20th century." [5]

The United Nations and World Health Organization found that reduction of tooth decay depends on the incorporation of fluoride both in developing teeth and on the exposure of tooth enamel to fluoride in the mouth. For both, the optimal fluoride concentration of drinking water was found to be 0.7-1.2 mg/litre, depending on climate, though supplementation of table salt or milk was also effective, as were fluoride tablets. Topical fluoride, as from toothpaste, provided additional benefit. The overall benefit of these methods depends on the initial incidence of cavities, the amount of fluoride in the diet, and the quality of dental care in the community.[6]

Dental fluorosis may pose a public health problem at high fluoride levels, and some communities need to reduce fluoride exposure. However, at optimal levels, fluorosis affects only a small proportion of the population, and to an extent that is "rarely considered aesthetically objectionable".[7]

Skeletal fluorosis can cause severe skeletal changes with an intake of 40-80 mg of fluoride per day for periods exceeding four years. Debilitating environmental fluorosis of a substantial portion of the population is found in several developing countries, where it is complicated by malnutrition. The effects can be slowly reversed through a reduction of fluoride intake and improved diet.[8]

Extreme industrial exposure can cause other health problem, such as nephritis. However, considerable evidence indicates that fluoride exposure does not cause cancer or birth defects, and it has not been shown to effect life expectancy.[9]

Opposition

Main article: Water fluoridation opposition

Water fluoridation by public authorities has provoked controversy. Opposition to water fluoridation arises from concern over the quality of the research demonstrating its efficacy and safety,[17] evidence suggesting that it may cause serious health problems, and a general resistance to the idea of compulsory 'mass medication' which takes away an individual's right to choose. Some concerns raised include:

  • The National Academy of Sciences' consensus that 2mg/L of fluoride in drinking water is harmful[18]
  • Cosmetic effects such as dental fluorosis (especially with concern to children) from an overdose of fluoride due to additional sources of fluoride (such as processed foods[19] and dental products).[19][20]
  • A link between high levels of fluoride and bone weakening[19] and more recently with bone cancer in boys.[19][21][22]
  • A lowering of IQ where drinking water fluoride levels were greater than 3 mg/L[23] which is within the limits of the standard set by the United States Environmental Protection Agency (EPA).[24]
  • The EPA published a study that reported that fluoridated water helped carry aluminum into rat's brains, producing Alzheimer's-like lesions.[25]
  • A disruption in endocrine function, especially in the thyroid.[26]

Bottled water and fluoridation

Some dental professionals are concerned that the growing use of bottled water may decrease the amount of fluoride exposure people will receive.[27] Some bottlers such as Danone have begun adding fluoride to their water.[28] Most bottlers, however, do not add fluoride, and fluoride concentrations are not usually labeled on the bottle. As a result, people who have fluoridated water supplies may receive less than the amounts of fluoride that fluoride proponents recommend if they choose bottled water over tap water. However, if consumers are merely choosing bottled water over other packaged drinks, such as orange juice or soda (when the latter is produced using water which has not been fluoridated), the effects may be absent, especially because consumers will still have fluoridated tap water for cooking.

Malfunctions in water fluoridation equipment

At least 17 incidences of fluoridation equipment malfunction, and their associated deaths and poisonings, have been documented in U.S. newspapers and medical journals. [10]

Perhaps the worst incident in the United States occurred in Hooper Bay, Alaska in 1992. When fluoridation equipment failed, a large amount of fluoride was released into the drinking water supply and 296 people were poisoned; 1 person died,[29] marking the first reported death due to fluoride toxicity caused by drinking water from a community water system.[30]

3 dialysis patients died and 6 were sickened at the University of Chicago Hospitals when the water filtration system failed on July 16, 1993. A hospital spokesperson said that the deaths and reactions “were consistent with fluoride exposure.” [11]

Schoolchildren in Portage, Michigan experienced vomiting and stomach pains when an electrical surge caused excessive amounts of fluoridation chemical to be injected into the school’s well in July 1991. [12]

In June, 2002, 23 employees of Humphry Systems Inc. in Dublin, California became ill after a fluoride pump malfunctioned near the business. All of the affected workers had drank from the water fountains, and experienced vomiting and nausea. [13]

34 restaurant diners became sick after a fluoridation equipment malfunction caused an acute outbreak of fluoride poisoning in August 1993, in Poplarville, Mississippi. Severe gastrointestinal illness was reported by 34 out of 62 customers in a 24 hour period. [14]

A dialysis patient died from fluoride overdose in Annapolis, Maryland when 1,000 gallons of excess fluoride chemical spilled into the drinking water on November 11, 1979. 7 others became critically ill. Brain damage, a heart attack and many other illnesses resulted. [15]

International status

Africa

South Africa's Health Department recommends adding fluoridation chemicals to drinking water in some areas. It also advises removal of fluoride from drinking water (defluoridation) where the fluoride content is too high.[31]

Asia

In China fluoridation is not permitted by law. [32]

Europe

Austria

Water has never been fluoridated in Austria.[33]

Belgium

Drinking water has never been fluoridated in Belgium. [34]

Denmark

Drinking water has never been fluoridated in Denmark.[35]

Finland

There was fluoridation of the drinking water of Kuopio eastern Finland and with a population of about 80,000 people (1.6% of the Finnish population) from 1959 to 1992.[36]

France

Fluoridation is not practised in France.[37][38]

Germany

In the former German Democratic Republic in several districts the drinking water was fluoridated but after the unification of Germany in 1990 fluoridation was stopped. In the Federal Republic of Germany there was in about 1952 a drinking water fluoridation experiment for one or two years.[39]

Hungary

In Hungary, one city, Szolnok, was fluoridated for a short time in the 1960s. Fluoridation is not presently practised in Hungary.[40]

Irish Republic

In the Republic of Ireland the majority of drinking water is fluoridated. The fluoridation agent currently used in Ireland for addition to drinking water supplies is hydrofluorosilicic acid (HFSA; H2SiF6).[41] The original legal basis for fluoridation of water in the Irish Republic until 2007 was the Fluoridation of Water Supplies Regulations, 1965. Those regulations set the level of fluoride in drinking water to between 0.8 to 1.0 ppm. Since 1st July 2007, the legal basis for the fluoridation of drinking water in Ireland is the Fluoridation of Water Supplies Regulations, 2007.[42] These regulations set the level of fluoride in drinking water to between between 0.6 and 0.8 ppm, with a target value of 0.7 ppm.

Luxemburg

Drinking water has never been fluoridated in Luxemburg.[43]

Netherlands

In the Netherlands the Supreme Court ruled there was no legal basis for fluoridation.[44]

Norway

There is no fluoridation of drinking water in Norway.[45]

Spain

Around 10% of the population receives fluoridated water.[46][47]

Sweden

In 1952, Norrköping in Sweden became one of the first cities in Europe to fluoridate its water supply.[48] It was declared illegal by the Swedish Supreme Administrative Court in 1961, re-legalized in 1962[49] and finally prohibited by the parliament in 1971,[50] after considerable debate. The parliament majority said that there were other and better ways of reducing tooth decay than water fluoridation. Four cities received permission to fluoridate tap water when it was legal.[51] An official commission was formed, which published its final report in 1981. They recommended other ways of reducing tooth decay (improving food and oral hygiene habits) instead of fluoridating tap water. They also found that many people found fluoridation to impinge upon personal liberty/freedom of choice, and that the long-term effects of fluoridation were not sufficiently known. They also lacked a good study on the effects of fluoridation on formula-fed infants.[52]

Switzerland

In Switzerland since 1962 two fluoridation programmes had operated in tandem: water fluoridation in the City of Basel, and salt fluoridation in the rest of Switzerland (around 83% of domestic salt sold had fluoride added). However it became increasingly difficult to keep the two programmes separate. As a result some of the population of Basel were assumed to use both fluoridated salt and fluoridated water. In order to correct that situation, in April 2003 the State Parliament agreed to cease water fluoridation and officially expand salt fluoridation to Basel.[53]

United Kingdom

Around 10% of the population of the United Kingdom receives fluoridated water.[54][55] The water supply in Northern Ireland has never been artificially fluoridated except in two small localities where fluoride was added to the water for about 30 years.[56]

North America

Canada

Approximately 40% of the Canadian population receives fluoridated water[57]

Implementation of fluoridation usually lies with provincial or city governments. Brantford, Ontario became the first city in Canada to fluoridate its water supplies in 1945. In 1955, Toronto approved water fluoridation, but delayed implementation of the program until 1963 due to a campaign against fluoridation by broadcaster Gordon Sinclair.[58] The city continues to fluoridate its water today.[59] There have been some recent decreases in the amount of fluoridation used, however, from 1 mg per litre to between 0.6 and 0.8 mg per litre. Historically, British Columbia has been the province with least percentage of its population receiving fluoridated water;[60] Greater Vancouver Water District member municipalities within the Metro Vancouver region receive water supplies that do not have added fluoride.[61]

On April 21, 2008, the town of Dryden, Ontario overwhelmingly rejected a water fluoridation proposal at the ballot box. [16]

United States

As of May 2000, 42 of the 50 largest U.S. cities have water fluoridation.[62] According to a 2002 study,[63] 67% of Americans are living in communities with fluoridated water. As of 2001, 19 states have at least 75% of their population receiving fluoridated water.[64]

The United States Centers for Disease Control and Prevention (CDC) states that water fluoridation is safe at a level of (0.7 mg/L-1.2 mg/L). The CDC also advises avoiding water with fluoride concentrations of 2mg/L or higher for children up to age 8.[65] There is a CDC database for researching the water fluoridation status of neighborhood water.[66]

In 1998, 70% of people polled in a survey conducted by the American Dental Association believed community water should be fluoridated, with 18% disagreeing and the rest undecided.[67]

The issue of whether or not to fluoridate water supplies frequently arises in local governments. For example, on November 8, 2005, citizens of Mt. Pleasant, Michigan voted 63% to 37% in favor of reinstating fluoridation in public drinking water after a 2004 ballot initiative ceased water fluoridation in the city.[68] At the same time, voters in Xenia, Ohio; Springfield, Ohio; Bellingham, Washington; and Tooele City, Utah all rejected water fluoridation.[69]

The cost of adding fluoridation chemicals to the water of 44 Florida communities has been researched by the State Health Office in Tallahassee.[70] In communities with a population of over 50,000 people, fluoridation costs were estimated at 31 cents per person per year. The estimated cost rises to $2.12 per person in areas with a population below 10,000. Unintended consequences, such as equipment malfunction, can substantially raise the financial burden, as well as the health risks, to the consumer.

Oceania

Australia

Australia has fluoridation in all but one state, Queensland, in which water fluoridation is under local government control. However, on 5 December 2007 Queensland Premier Anna Bligh announced fluoridation of most of Queensland's water supply will begin in 2008.[71] The city of Geelong, west of Melbourne, does not fluoridate its water supplies. This is despite the fact that all of Melbourne's water is fluoridated. The first town to fluoridate the water supply in Australia was Beaconsfield, Tasmania in 1953.[72] Fluoridation commenced January 7th, 2008 in the City of Gosford, New South Wales.[73]

New Zealand

New Zealand has fluoridated nearly all water-supplies except those in remote areas. The use of water fluoridation first began in New Zealand in Hastings in 1954. A Commission of Inquiry was held in 1957 and then its use rapidly expanded in the mid 1960s.[74]

South America

In Brazil, about 45% of cities have a fluoridated water supply. Government studies reported a decrease in cavities in the affected populations of between 40% and 80%.[75]

In Chile 70.5% of the population receive fluoridated water (10.1 million added by chemical means, 604,000 naturally occurring).[76]

See also

References

  1. ^ Reeves T.G.: "Technical aspects of water fluoridation in the United States and an overview of fluoridation engineering world-wide", Community Dent. Health 13: Suppl. 2 (1996) 21-26.
  2. ^ Bellack E.: "Fluoridation Engineering Manual", Report EPA-520/9-74-022, (1974).
  3. ^ Meiers, Peter: "Early Fluoride research in Europe" from the Fluoride History website, page accessed 21 May, 2006.
  4. ^ a b History of Dentistry in the Pikes Peak Region,Colorado Springs Dental Society webpage, page accessed 25 February, 2006.
  5. ^ Meiers, Peter: "The Bauxite Story - A look at ALCOA", from the Fluoride History website, page accessed 12 May, 2006.
  6. ^ Dean, H.T. "Classification of mottled enamel diagnosis." Journal of the American Dental Association, 21, 1421 - 1426, 1934.
  7. ^ Dean, H.T. "Chronic endemic dental fluorosis." Journal of the American Dental Association, 16, 1269 - 1273, 1936.
  8. ^ Meiers, Peter: "Gerald Judy Cox".
  9. ^ Cox, G.J., M.C. Matuschak, S.F. Dixon, M.L. Dodds, W.E. Walker. "Experimental dental caries IV. Fluorine and its relation to dental caries. Journal of Dental Research, 18, 481-490, 1939. Copy of original paper can be found here.
  10. ^ Klein H., Palmer C.E.: "Dental caries in American Indian children", Public Health Bulletin, No. 239, Dec. 1937
  11. ^ After 60 Years of Success, Water Fluoridation Still Lacking in Many Communities. Medical News Today website, accessed 26 February, 2006.
  12. ^ Ast, D.B., D.J. Smith, B. Wacks, K.T. Cantwell. "Newburgh-Kingston caries-fluorine study XIV. Combined clinical and roentgenographic dental findings after ten years of fluoride experience." Journal of the American Dental Association, 52, 314-25, 1956.
  13. ^ Brown, H., M. Poplove. "The Brantford-Sarnia-Stratford Fluoridation Caries Study: Final Survey, 1963." Canadian Journal of Public Health,56, 319–24, 1965.
  14. ^ Diesendorf, Mark The mystery of declining tooth decay Nature, July 10, 1986 http://www.nature.com/nature/journal/v322/n6075/pdf/322125a0.pdf
  15. ^ Diesendorf, Mark The mystery of declining tooth decay Nature, July 10, 1986
  16. ^ "Populations Receiving Optimally Fluoridated Public Drinking Water --- United States, 2000". Centers for Disease Control and Prevention. Retrieved 2008-01-31.
  17. ^ Centre for Reviews and Dissemination, University of York, York, UK. http://www.york.ac.uk/inst/crd/fluorid.htm Fluoridation of Drinking Water: a Systematic Review of its Efficacy and Safety. Accessed 2007-06-23
  18. ^ Fluoride in Drinking Water: A Scientific Review of EPA's Standards
  19. ^ a b c d Scientific American Jan. 2008 p.80 Article
  20. ^ Timing of Fluoride Intake in Relation to Development of Fluorosis on Maxiallry Central Incisors. L. Hong, S. Levy at al. Community Dentistry and Oral Epidemiology Vol. 34, No. 4, pp 299-309, Aug 2006
  21. ^ Age-Specific Fluoride Exposure in Drinking Water and Osteosarcoma. E. Bassin et al. Cancer Causes and Control Vol. 17, No. 4, pp 421-428, May 2006
  22. ^ Caution Needed in Fluoride and Osteosarcoma Study. C. Douglas, K. Joshipura Cancer Causes and Control Vol. 17, No. 4, pp 481-482, May 2006
  23. ^ http://www.fluoride-journal.com/00-33-2/332-74.pdf
  24. ^ http://www.epa.gov/ogwdw/hfacts.html EPA Ground Water & Drinking Water
  25. ^ The Fluoride Deception, Christopher Bryson, Seven Stories Press, 2004
  26. ^ 'Second Thoughts about Fluoride,' Reports Scientific American | Reuters
  27. ^ Smith, Michael. "Bottled Water Cited as Contributing to Cavity Comeback", from the MedPage Today website, page accessed 29 April, 2006.
  28. ^ Press release from the Water Industry News website]
  29. ^ Flanders, R. A. (May–June 1993). "Fluoride overfeeds in public water supplies". Illinois dental journal. 62 (3): 165–169. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: date format (link)
  30. ^ Gessner, B. D. (January 1994). "Acute fluoride poisoning from a public water system". New England journal of medicine. 330 (2): 95–99. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  31. ^ "Water Fluoridation - The Facts", from South Africa's Department of Health website, page accessed April 29, 2006.
  32. ^ Gao Xishui, Deputy Director General, Department of International Cooperation, Ministry of Health, China, March 1, 2000. Ministry of Health Statement http://fluoridation.com/c-china.htm
  33. ^ Austria Water Department Statement www.fluoridation.com/c-austria.htm
  34. ^ [www.fluoridation.com/c-belgium.htm Statement from Brussels, Belgium]
  35. ^ Royal Danish Embassy Statement www.fluoridation.com/c-denmark.htm
  36. ^ Finland Social Affairs and Health Statement www.fluoridealert.org/finland.jpeg
  37. ^ Directeur de la Protection de lEnvironment Statement www.fluoridealert.org/france.jpeg
  38. ^ http://www.fluoridealert.org/govt-statements.htm
  39. ^ www.fluoridealert.org/germany.jpeg
  40. ^ Statement of Eszter Szovenyi, Ministry for Environment, Republic of Hungary, January 24, 2000 http://fluoridation.com/c-hungary.htm
  41. ^ Report of the Forum on Fluoridation 2002 - Dept of Health and Children - Ireland
  42. ^ Statutory Instrument No. 42 of 2007 - Fluoridation of Water Supplies Regulations 2007
  43. ^ www.fluoridealert.org/luxembourg.jpeg
  44. ^ Statement of Wilfred Reinhold, Directorate Drinking Water, Netherlands www.fluoridation.com/c-netherlands.htm
  45. ^ Norway National Institute of Public Health Statement www.fluoridation.com/c-norway.htm
  46. ^ Mullen, Joe. "History of Water Fluoridation", British Dental Journal, 2005, page accessed April 29, 2006.
  47. ^ http://www.nature.com/bdj/journal/v199/n7s/full/4812863a.html British Dental Journal (2005); 1-4. doi: 10.1038/sj.bdj.4812863Help History of Water Fluoridation by Dr Joe Mullen
  48. ^ Larsson, Gerhard (1981). Fluor i kariesförebyggande syfte - Betänkande av fluorberedningen (in Swedish). Stockholm: Statens offentliga utredningar / Socialdepartementet. p. 12. SOU 1981:32. {{cite book}}: Check date values in: |year= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)CS1 maint: year (link)
  49. ^ "Fluoreringsfrågan avgjord". Västmanlands läns tidning (in Swedish). 1962-11-22. {{cite news}}: Check date values in: |date= (help)
  50. ^ "Stopp för fluor". Västmanlands läns tidning (in Swedish). 1971-11-19. p. 1.
  51. ^ Larsson, Gerhard (1981). Fluor i kariesförebyggande syfte - Betänkande av fluorberedningen (in Swedish). Stockholm: Statens offentliga utredningar / Socialdepartementet. pp. 56–57. SOU 1981:32. {{cite book}}: Check date values in: |year= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)CS1 maint: year (link)
  52. ^ Larsson, Gerhard (1981). Fluor i kariesförebyggande syfte - Betänkande av fluorberedningen. Stockholm: Statens offentliga utredningar / Socialdepartementet. p. 29. SOU 1981:32. {{cite book}}: Check date values in: |year= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)CS1 maint: year (link)
  53. ^ J. MEYER and P. Wiehl in Schweiz Monatsschr. Zahnmed 2003; 113: 702 (in French) and 728-729 (in German)
  54. ^ Mullen, Joe. "History of Water Fluoridation", British Dental Journal, 2005, page accessed April 29, 2006.
  55. ^ http://www.nature.com/bdj/journal/v199/n7s/full/4812863a.html British Dental Journal (2005); 1-4. doi: 10.1038/sj.bdj.4812863Help History of Water Fluoridation by Dr Joe Mullen
  56. ^ Belfast Statement www.fluoridealert.org/Northern-Ireland.jpeg
  57. ^ "Fluorides and Human Health", from the Health Canada website, page accessed March 25, 2006.
  58. ^ "Gordon Sinclair's rant", from the Canadian Broadcasting Corporation Archives website, page accessed March 27, 2006.
  59. ^ "Water supply - R. L. Clark Filtration Plant", from Toronto's website, page accessed March 27, 2006.
  60. ^ "Ambient Water Quality Criteria for Fluoride", from the Environmental Protection Division of British Columbia's Ministry of Environment website, page accessed March 27, 2006.
  61. ^ Drinking Water FAQ
  62. ^ The Benefits of Fluoride, from the Centers for Disease Control and Prevention website, accessed 19 March, 2006.
  63. ^ Fluoridation Status: Percentage of U.S. Population on Public Water Supply Systems Receiving Fluoridated Water, from the Centers for Disease Control and Prevention website, accessed 19 March, 2006.
  64. ^ National Oral Health Surveillance System: Public Water Supply, from the Centers for Disease Control and Prevention.
  65. ^ http://www.cdc.gov/fluoridation/faqs.htm: Community Water Fluoridation :FAQ
  66. ^ Oral Health - My Water's Fluoride
  67. ^ American Dental Association Survey Center. 1998 consumers' opinions regarding community water fluoridation. Chicago, Illinois: American Dental Association, 1998
  68. ^ Crozier, Stacie. "Michigan town votes to return fluoridation" November 30, 2005.
  69. ^ No Forced Fluoride in Bellingham, Washington (Fluoride)
  70. ^ Ringelberg, M. L., S. J. Allen, L. J. Brown. "Cost of fluoridation: 44 Florida communities.", abstract from PubMed website, page accessed 19 March, 2006.
  71. ^ Qld to get fluoridated water - ABC News (Australian Broadcasting Corporation)
  72. ^ Editors: Graham Aplin, S.G. Foster and Michael McKernan, ed. (1987). "Tasmania". Australians:Events and Places. Sydney, NSW, Australia: Fairfax, Syme & Weldon Associates. pp. page 366. ISBN 0-521-34073-X. {{cite book}}: |editor= has generic name (help); |pages= has extra text (help)
  73. ^ Gosford City Council Water Information Centre
  74. ^ New Zealand Ministry of Health
  75. ^ Fluoretação da Água em Sistema Público de Abastecimento, page accessed April 29, 2006.
  76. ^ Information from the Oral Health Department of the Chilean Ministry of Health. December 2004.
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