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Case 4: Fluoride
Transcript of Case 4: Fluoride
Case 4: Fluoride
Claim #6 - Research studies have linked fluoride with reduced IQ in children.
Is this true, and what leads to this claim?
The Origin of Fluorides
" Fluoride is a by-product from the phosphate fertilizer industry"
This is not an entirely false statement. The naturally occurring phosphorite rock, which is used to harvest fluoride additives, is also used to make phosphate fertilizer (11). However, these fluoride additives are not toxic waste as the statement implies, and which is the common misconception.
There are high quality standards applied to these products which are highly monitored and regulated for public safety by the American Water Works Association, the National Sanitation Foundation, and the American National Standards Institute (12).
The City Council of a large metropolitan area is considering a new city ordinance that will require fluoridation of public drinking water, based on its goal of improving children's oral health, specifically by reducing dental caries and the high costs of emergency room visits by children with odontogenic infections. During hearings of adoption of the ordinance, anti-fluoride groups cite many adverse outcomes that could result from water fluoridation.
Initial Discovery of the Oral Health Benefits of Fluoride
How does Fluoride get in the water?
FSA, which is derived from the condensed gas products from heating of phosphorite rock with sulfuric acid, is combined with large water supplies and adjusted to meet the 1.0 ppm guidelines established (11).
Fluoride in Water
Sodium Fluoride additives, made from FSA, are combined with toothpastes, mouthwashes and even floss to ensure adequate fluoride is available to everyone (12). Fluoride can strengthen teeth and make them more resistant to caries.
Fluoride in Dentistry
-Colorado Brown Stain - 1901
-Dr. McKay (r) and Dr. Green Vardiman Black (l)
-Mottled enamel was a result of developmental imperfections in children's teeth
-Resistant to decay
-Early 1930s Aluminum Company of America (ALCOA) study finds high levels of fluoride in water supply
-Late 1930s National Institute of Health (NIH) study to determine upper limits of fluoridation without causing enamel fluorosis
-1945 Grand Rapids Water Fluoridation Study: 15 years, 30,000 schoolchildren, drop of more than 60% in caries rate
-Present Day: majority of toothpastes, water fluoridation projects, fluoride mouth rinse programs (1)
1: "The Story of Fluoridation." The Story of Fluoridation. Ed. Staff L. Member. National Institute of Dental and Craniofacial Research, 18 July 2013. Web. 11 Sept. 2013
3. American Dental Association (2005). Fluoridation facts. American Dental Association. Retrieved from http://www.ada.org/sections/newsAndEvents/pdfs/fluoridation_facts.pdf
4. Environmental Protection Agency (2013, July 13). Basic Information about fluoride in drinking water. Retrieved September 11, 2013, from http://water.epa.gov/drink/contaminants/basicinformation/fluoride.cfm#four
5. Fagin, D. (2008). Second thoughts about fluoride. Scientific American. Retrieved from http://www.waterloowatch.com/Index_files/Second%20Thoughts%20About%20Fluoride,%20Scientific%20American%20Jan-08.pdf
6. Fluoride Action Network (2012, April). The minimum dose that produces acute fluoride toxicity. Retrieved September 11, 2013, from http://www.fluoridealert.org/studies/acute02/
7. Neisser U (1997). "Rising Scores on Intelligence Tests". American Scientist 85: 440–7.
8. Grandjean P, Landrigan P. Developmental neurotoxicity of industrial chemicals. Lancet. 2006;368(9553):2167–2178.
9. U.S. EPA. EPA and HHS Announce New Scientific Assessments and Actions on Fluoride: Agencies Working Together to Maintain Benefits of Preventing Tooth Decay while Preventing Excessive Exposure. 2011 Available: http://yosemite.epa.gov/opa/admpress.nsf/bd4379a92ceceeac8525735900400c27/86964af577c37ab285257811005a8417!OpenDocument
10. Environ Health Perspect. 2012 October; 120(10): 1362–1368. Published online 2012 July 20. doi:10.1289/ehp.1104912
11. "CDC - Water Fluoridation Additives - Engineering Fact Sheet - Community Water Fluoridation - Oral Health." Centers for Disease Control and Prevention. N.p., 22 Aug. 2013. Web. 12 Sept. 2013. <http://www.cdc.gov/fluoridation/factsheets/engineering/wfadditives.htm>.
12. "Are fluoride additives toxic waste? | Fluoride Facts Portland." Fluoride Facts Portland. N.p., n.d. Web. 12 Sept. 2013. <http://www.fluoridefactsportland.com/facts/toxicwaste/>.
13. Pandey, J., and U. Pandey. "Fluoride Contamination And Fluorosis In Rural Community In The Vicinity Of A Phosphate Fertilizer Factory In India." Bulletin of Environmental Contamination and Toxicology 87.3 (2011): 245-249. Print.
14. World Bank. Water Quality Management: Policy and Institutional Considerations. 2006 Available: http://siteresources.worldbank.org/INTEAPREGTOPENVIRONMENT/Resources/China_WPM_final_lo_res.pdf [accessed 13 June 2012]
15.Water: Basic Information about Regulated Drinking Water Contaminants, United states Envionmental protection agency http://water.epa.gov/drink/contaminants/basicinformation/fluoride.cfm#two
16. Effects of fluoridated drinking wateron dental caries in Australian adults.Slade GD, Sanders AE, Do L,Roberts-Thomson K, Spencer AJ.J Dent Res 2013;92:376.
17.Künzel W, Fischer T, Lorenz R, Brühmann S, Decline of caries prevalence after the cessation of water fluoridation in former east Germany. Community dentistry and oral epidemiology. 200; 28 382-9
18. "CDC - Dental Fluorosis - Safety - Community Water Fluoridation - Oral Health." Centers for Disease Control and Prevention. N.p., n.d. Web. 11 Sept. 2013. <http://www.cdc.gov/fluoridation/safety/dental_fluorosis.htm#a3>.
19. Li, Wu, and Pamela DenBesten. "Chronic Fluoride Toxicity: Dental Fluorosis." Monographs in Oral Science 22 (2011): 81-96. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3433161/. Web. 11 Sept. 2013.
20. "Fluorosis: Symptoms, Causes, and Treatments." WebMD Children's Health Center - Kids health and safety information for a healthy child. N.p., n.d. Web. 11 Sept. 2013. <http://children.webmd.com/fluorosis-symptoms-causes-treatments>.
21. Izuora, Kenneth, et al. "Skeletal fluorosis from brewed tea." Journal of Clinical Endocrinology & Metabolism 96.8 (2011): 2318-2324.
22. "Fluoride Action Network | Skeletal Fluorosis." Fluoride Action Network | Broadening Public Awareness on Fluoride.. N.p., 11 Sept. 2013. Web. 12 Sept. 2013. <http://www.fluoridealert.org/issues/health/skeletal_fluorosis/>.
23: Hellwig, E., and A. M. Lennon. "Systemic versus Topical Fluoride." Caries Research 38.3 (2004): 258-62. Karger.com. Caries Research. Web.
What is an IQ?
IQ -Intelligence Quotient is the scored derived from one of several standardized tests designed to assess intelligence (7)
Claim 1: "Swallowing Fluoride Provides Little Benefit to Teeth"
Fluorosis Case Study
In a case study monitoring the effects of fluoride in 10 cities in India, which were within a short distance of a phosphate fertilizer plant, fluorosis was very common (13). However, Fluoride was shown to be in high levels in the water, air and food contaminants. Naturally occurring Fluoride exists in these ares with or without the fertilizer industry. The study claims that a combination of high Fluoride exposure from drinking water, food items, and even from the air they breathe can result in dental fluorosis and even skeletal fluorosis over time (13). Excessive exposure to Fluoride, like many other substances, can be toxic. However, it is does not prove that these contaminants are a direct result of the factory. Those suffering from fluorosis could be affected by high levels of naturally occurring fluorides in the well water and other common sources.
95% of the population will have an IQ between 70 and 130
Tests used - Raven’s Progressive Matrices and Vocabulary (10)
Fluoride must pose a danger because there's a warning label on the toothpaste."
EPA's Drinking Water Regulations for Fluoride
1974- Safe Drinking Water Act
Requires EPA to determine the level of contaminants in drinking water at which no adverse health effects are likely to occur (4).
Enforceable Regulation for Fluoride by EPA
Maximum Contaminant Level (MCL) at 4.0 mg/L or 4.0 parts per million for drinking water (ppm). (4)
The National Research Council (NRC) suggests that the MCL is high and should be lowered. (4)
United States Public Health Service (USPHS)
established the optimum concentration for fluoride in the water in the United States to be in the range of
0.7 to 1.2 ppm.
U.S Wide Average Tap Water: 0.71 ppm (5)
How Does it Work?
Naturally occurring phosphorite rock, made up of calcium phosphate, limestone, minerals and apatite, is heated with sulfuric acid, which creates a phosphoric acid-gypsum mixture. During the heating process, Hydrogen Fluoride and Silicon tetrafluoride gases that are released from the reaction are gathered using vacuum evaporators (11). By condensing these gases, a solution of 23% Fluorosilcic Acid (FSA) and 77% water is produced (11). 95% of the fluoride in drinking water comes from this process (11). Hydrogen Fluoride manufacturing makes up the other 5%. This methods have remained popular for over 60 years because it produces very affordable and also very pure FSA which, because it is water based, is easily added to a large water supply (11). Sodium Fluorosilicate and Sodium Fluoride are dry additives that come from FSA and can also be dissolved in water and used. (11)
Review of Studies
Too Much of a Good Thing?
Benefits: Prevention of Caries
However, extreme amounts may lead
to illnesses or even death.
Fluoride is in many foods, beverages and dental products. The concern to use this as the cavity fighting chemical may result in overconsumption, especially in young children. (5)
Topical vs. Systemic
How much fluoride must be ingested to cause
Acute fluoride toxicity will not occur through the ingestion of optimally fluoridated water (3)
Ingestion of 0.1 to 0.8 milligrams of fluoride for every kilogram of bodyweight --> Acute Fluoride Poisoning
Symptoms: gastric pain, nausea, vomiting, and headaches. (6)
Death can occur if
5-10 grams of sodium fluoride
( 155 lbs adult man)
10,000- 20,000 times as much fluoride as consumed in a single 8 oz glass of optimally fluoridated water(3).
Chronic fluoride toxicity- after 10 or more yrs of exposure to levels higher than those associated with optimal fluoride intake in drinking water( 3)
-strengthens teeth already present
-professionally applied therapies
-ingested into the body
-incorporated into forming tooth structures
-also provides topical because of presence in saliva
-dietary fluoride supplements (2)
Fluoride in Toothpaste
"Do not swallow. Use only a pea-sized amount for children under six. To prevent swallowing, children under six years of age should be supervised in the use of toothpaste." The new FDA labels are consistent with the ADA statements, with the exception of the poison control warning. (3)
ADA states that optimally fluoridated water will not cause adverse health effects on:
-no association with cancer
-no effect on human enzyme activity
-no adverse effect on thyroid gland function
-no adverse effect on human reproduction, fertility, or birth rates
-no neurological effects
-does not cause or contribute to heart disease
-does not cause or worsen kidney problems
Fluoride toothpaste usually contains 1,100-1,400 ppm or 1 mg of F per gram of toothpaste (6)
Other health effects
-Increase risk of bone fracture & osteosarcoma
-U.S Govt National Toxicology Program 1990 Study
-Elise B. Basin- Harvard School of Medicine (2006)
Why should the US engage in water fluoridation?
Individuals exposed to fluoridated water after having done without it in the past as children or adults exhibited a significant reduction in Caries (Sanders)
Dental Fluorosis as defined by the CDC
Defined as a change in the mineralization of the dental hard tissues (enamel, dentin, and cementum) caused by long-term ingestion (eating and drinking) of fluoride during the period of tooth development prior to eruption into the mouth (first 8 years of life for most permanent teeth excluding third molars). Once the tooth erupts, dental fluorosis refers to a range of visually detectable changes in enamel. Changes range from barely visible lacy white markings in milder cases to converged opaque areas and pitting of the teeth in severe forms. After eruption the pitted areas can become stained yellow to dark brown. 
Decreases the prevalence of caries
Most effective way of reaching the entire population
Will benefit members of all social classes
Greater chance of developing caries than developing fluorosis
Endorsed by more than 150 science and health organizations
Federation Dentaire Internationale (FDI)
International Association for Dental Research (IADR)
World Health Organization (WHO) (15).
Reasons some developed
countries are against fluoridation
Who does dental fluorosis affect?
97% of the Western European Population do not fluoridate their water.
Considered a drug by the FDA because it's a form of medical treatment
Claimed to be unethical without informed consent
water consumption not controlled
Risk of fluorosis
Fluoride in many other sources
Not an essential nutrient
low levels in breast milk
Swallowing fluoride has no benefits (15)
Since enamel and dentin fluorosis only occurs when the teeth are forming, it usually affects kids of 8 years old and younger. Most of the teeth have finished forming under the gums by this age. 
Why do people develop dental fluorosis?
Cohort study done in rural and urban Australia.
2270 adults born before 1960 (re- fluoridated cohort)
1509 adults born 1960-1990 (post -fluoridated cohort)
DMFT =(years fluoridated water X concentration of fluoride) / age
measured caries experience based on # of years exposed to fluoridated water(16).
Dental fluorosis is caused by the ingestion of large amounts of fluoride during tooth development. The timing and duration of fluoride ingestion also influences the severity of dental fluorosis. , 
"Children in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas" (10)
Inverse relationship between duration of exposure to fluoridated water and dental caries in children and adults.
Weaker relationship between the dosage of fluoridation and prevalence of caries (16).
What were the Findings?
Data collected from: Environ Health Perspect. 2012 October; 120(10): 1362–1368. Published online 2012 July 20. doi: 10.1289/ehp.1104912
How does fluorosis occur?
Developing brain vs. mature brain (8)
U.S. DHHS and EPA trying to change recommended intake from 0.7 - 1.2 mg/L to 0.7 mg/L (9)
Rural Chinese communities (9)
Safe water 5 year plan by Chinese government (14)
Disclaimer: the mechanism of fluorosis is not completely understood at this time
An incomplete removal of amelogenin proteins under influence of fluoride during tooth development leads to fluorosis
Fluoride inhibits the enzymatic degradation of amelogenin proteins. This delays their removal from the developing enamel.
This leads to hypomineralization under the enamel surface. In mature enamel, the enamel matrix proteins are replaced by crystals.
Furthermore, fluoride stimulates the ameloblast to produc more enamel matrix protein. These proteins are retained in the mature enamel preventing the crystallization.
Ultimately there exists a hypomineralized subsurface lesion covered by a well mineralized outer layer of enamel. The subsurface enamel becomes more porous. The porosity of subsurface enamel increases as the level of fluoride in the body increases during tooth development.
Enamel apatite is primarily made up of hydroxyapatite crystals.
When fluoride levels are high the hydroxyapatite is converted to fluoroapatite. 
Eastern German study reported decline in prevalence of caries following discontinuation of fluoridation of water
Retrospective study to compare DMFT in Zittau and Spremberg
subjects had been studied repeatedly examined 20 years prior for oral hygiene
1993 marked cessation of fluoridation (17).
Decrease amount could be within the measurement error of IQ testing
High and low groups could be misclassified (10)
Not concrete evidence based in the U.S.
Fluorosis affects nearly one in every four Americans ages 6 to 49
It’s most prevalent in those ages 12 to 15
Majority of cases are mild
Only about 2% are considered “moderate”
Less than 1% are “severe” 
Dental Fluorosis in the General Population
Debilitating bone disease that arises from excessive consumption of fluoride.
Many doctors in the US fail to detect skeletal fluorosis due to the similarities in symptoms to other bone and joint diseases.
Similar to Osteoarthritis and Rheumatoid arthritis
Case study: A woman from Georgia had crippling skeletal fluorosis. She appeared to suffer from kyphosis (hunchback). It took doctors 18 years to diagnose her with skeletal fluorosis. The high levels of fluoride in her diet came from brewed tea 
“Although skeletal fluorosis has been studied intensely in other countries for more than 40 years, virtually no research has been done in the U.S. to determine how many people are afflicted with the earlier stages of the disease, particularly the preclinical stages." 
Significant decrease in the prevalence of caries during and after the cessation of fluoridation in both cities (1973-1993)
Unlikely due to a single factor
greater utilization of dental services
40.3% with fluoride topical and oral varnishes
10-15% to 88% increase in usage of fluoride toothpaste
increase in F-salts after 1992
90% children received Vitamin D3 and NaF for rickets
doubled usage of antibiotics
national levels decreased by 20% (1990-1993) (17).
Other methods of public delivery of Fluoride
Slow release devices
Dietary Supplements/ tablets
Clinical topical fluorides
Is Water fluoridated in Houston?
2012 Drinking water quality report
Fluoride levels of .2-.5 ppm
below the EPA's MCLG 4PPM
Although Fluoridation decreases risk of caries many countries do not add fluoride to their water
Many different methods of fluoridation available
Reason to not include fluoridation based on beliefs on "individualized therapy". (15)
possible to have good oral health if you maintain good oral hygiene
Chances of developing fluorosis from drinking water is unlikely
Houston does include fluoride in the water supply
-Showed that ingestion of fluoride (systemically) was important in the development of the teeth and then after the teeth had developed it played an important role in the remineralization of the enamel
-Presence in the plasma during the developmental stage and also in the saliva after the teeth have erupted (23)
Claim 2: Fluoridation of drinking water is harmful because it causes a condition called fluorosis
"Even though many of the studies on children in China differed in many ways or were incomplete, the authors consider the data compilation and joint analysis an important first step in evaluating the potential risk" (24)