Fluoride in Public Drinking Water: A Students Perspective

A Scientific Editorial

Jeff Sauer

Disclaimer

This brief view of the topic is not, in any way, exhaustive.

Introduction.

Dr. Frederick McKay’s observations / accomplishments 1901-- 1931 Colorado Brown Stain Oakley, Idaho success

H. Trendley Dean’s expansion of McKay’s work 1931--1942 Fluorosis Index Hypothesis of 1.0 ppm F as optimum

1945 four city field trial tremendous success (60%) led to nationwide incorporation of adjusted fluoride drinking water concentration

Demineralization / Mineralization

Enamel is the very hard, visible portion of the crown that coats dentin

Hydroxyapatite, (Ca5(PO4)3OH) comprises the largest fraction of enamel

Mature enamel has no cells and is not alive

Demineralization / Mineralization

Demineralization / Mineralization

Caries formation is bacterially mediated

Streptococcus mutans break down starches into organic acids which dissolve enamel

If fluoride is present in saliva at sufficient concentration, it substitutes for the hydroxyl group altering the shape and density of the crystal

Fluoride substituted hydroxyapatite, or fluoroapatite, increases tooth enamel hardness and bone mineral strength, under ideal conditions.

Observations

A plot of Decayed Missing or Filled Permanent Teeth (DMFT) versus year of subject, Yiamouyiannis, 1990 (data collected in 1986-1987 by the National Institute for Dental Research)

Observations

Hellwig mentions a study by Lemke et al., who concludes, “the inhibiting effect tends to persist as long as fluoride exposure is continued but tends to be gradually lost after fluoride exposure is discontinued”.

Hellwig and Lennon, 2004 conclude that the kinetics of demineralization / remineralization is the primary mode of action of fluoride.

The conclusion of Featherstone’s 1999 study is, “fluoride works primarily via topical mechanisms”.

Observations

A study by a German research team measured the amount of fluoride ingested from a toddler’s tooth brushing experience (using fluoridated toothpaste) at 930 +/- 390 µg/kg, swallowing about 274 +/- 176 µg/kg

This shows that brushing with fluoridated toothpaste is a significant source of fluoride

Conclusion

Fluoride from drinking water is no longer a single line of defense against caries

The shrinking difference of dental caries between communities with and with out the additive presents a question: If the difference is shrinking due to increased availability of fluoridated over-the-counter products, does fluoride act systemically or topically?

Conclusion

Comparing tooth brushing fluoride exposure between a toddler and an adult is not sound, but the point is that fluoride exposure from brushing is significantly higher than the 4.0 mg/day recommended by professionals

Fluoridation of drinking water does indeed have beneficial properties. There are efforts to standardize all of Chinas drinking water, plus Pakistan is now setting up infrastructure. Both countries, similar to the US, had successful field trials.

In America, the need for drinking water fluoridation may no longer be necessary as our over-the-counter fluoridated dental products could more than make up for fluoride free drinking water.

References

1 American Dental Association, Oral Health Topics A–Z. http://www.ada.org/public/topics/fluoride/facts/index.asp (accessed May, 2005 )2 Linus Pauling Institute, Macronutrient Information Center. http://lpi.oregonstate.edu/infocenter/minerals/fluoride/ (accessed May, 2005)3 Lindsey, R., Fluoride And Bone – Quantity Versus Quality, NEJM 1990, 322, 845- 846. 4 Jarvis, J.T. Fluoridation, http://www.ncahf.org/articles/e-i/fluoride.html (accessed April, 2005)5 CDC Oral Health Resources, Oral Fact Sheet. http://www.cdc.gov/OralHealth/factsheets/fl-stats-us2000.htm (accessed April, 2005)6 Achievements in Public Health, 1900–1999 : Fluoridation of Drinking Water to Prevent Dental Caries MMWR [Online] 1999, 48 (41), 933-9407 Yiamouyiannis, J. A.; Water Fluoridation and Tooth Decay: Results from the 1986– 1987 National Survey of US Schoolchildren; Fluoride: J. of Inter. Soc. for F Res. 1990, 23 (2), 55-67.8 Lemke, C.W., Doherty, J.M., Arra, M.C.; Controlled fluoridation: The dental effects of discontinuation in Antigo, Wisconsin. J. Am. Dent. Res. 1985, 64, 465-469. 9 Hellwig. E., Lennon, A.M., Systemic versus Topical Fluoride. Caries Research 2004, 38, 258-262.10 Featherstone, J.D.B., Prevention and reversal of dental caries: role of low level fluoride. Community Dentistry and Epidemiology 1999, 27 (1), 31-40. 11 Haftenberger, M., Viergutz, G., Neumeister, V. Hetzer, G. Totla fluoride intake and urinary excretion in German children aged 3-6 years. Caries Research 2001, 35 (6),

451-457.