The Backstory on Fluoride in Community Water Supplies and Why We Need It



Hi, I’m Dr. Rob Karlinsey, an oral health resource for clinicians, researchers, and laypeople alike. When I give presentations about preventive dentistry, which usually involves fluoride and remineralization, I’m often asked several questions. Because I’m finding that some of these questions are frequently asked and are relevant to today, I thought I’d prepare and share with you several unscripted Q&A videos regarding my opinions.

So here’s a common question I receive regarding fluoride and community water supplies.

  1. Question: There is some thought that fluoride isn’t healthy, may actually be harmful, and in fact, should not be added to community drinking water – what is your response?
  2. Answer: To explain my opinion, I think it’s first helpful to review some general facts about fluorine
    1. Fluoride is the ionic form of fluorine and would be found, for instance, in aqueous solutions
    2. Fluorine is the 13th most abundant element in Earth’s crust
      1. In fact, it’s more abundant than carbon, chlorine, copper
      2. Some common natural mineral sources of fluorine include:
        1. Fluorite, which is especially common in the Rocky Mountain region,
        2. Malladrite, which is a silicofluoride volcanic rock found, for example, on and about Mount Vesuvius in the Naples, Italy region; and,
        3. Phosphorite rock., which includes fluorapatite.
          1. It is used, for example, to produce phosphate for fertilizer purposes; and,
          2. It’s also used to produce silicofluoride for water fluoridation
            1. [Fluorine evolved (via sulfuric acid addition), collected, condensed to hydrofluorosilic acid (FSA)]
      3. Fluorine is also common in about 30% of agrochemicals and 20% of pharmaceuticals
        1. Why? The Carbon-Fluorine bond is among the strongest bonds and because of this it is used for metabolic stability purposes
        2. Some common blockbuster drugs that utilize fluorine:
          1. Prozac (anti-depressant)
          2. Lipitor (cholesterol-lowering)
          3. Ciprobay (antibiotic)
  1. Presently, in those regions supporting water fluoridation, fluoride is added to community water supplies in the form of either sodium fluoride or silicofluorides.
    1. Sodium fluoride is in powder form and is most economical for small communities.
    2. Silicofluorides are in liquid form and are most cost effective for moderate to large communities. In fact, about 90% of all water fluoridation utilizes this type of fluoride.
      1. FSA since the 1950s; (
    3. When fluoride is artificially added to a water supply, this is done at concentrations near 1 ppm F, (even slightly above and below)
      1. This is important for two reasons:
        1. it helps maintain dissociation (meaning, availability of the fluoride ion), and,
        2. facilitates uptake and clearance from the body upon ingestion.
      2. Do these sources affect the body differently? No, multiple pharmacokinetic studies show there are no significant differences in uptake or clearance of these fluoride sources
  2. But what’s the backstory of fluoride and the water supply, a la pre-1950s?
    1. Some of the earliest observations of mottled teeth were in Naples, Italy made by military personnel prior to 1910. The observed mottling/discolorations of the Neapolitan people likely originated from leaching of fluoride from silicofluoride mineral (e.g., Malladrite) into the water supply.
    2. Unexplained mottling of enamel published in 1916 in the Rocky Mountain region, which is a region especially high in fluorite! Curiously, those with mottled teeth were less susceptible to tooth decay…
    3. And, other regions were also soon reported mottling. So in the 1930s, Dean (first director of the United States National Institute of Dental Research) investigated various regions reporting high incidences of enamel mottling
      1. This was especially true in industrial activity regions (for instance, Alcoa in the southern U.S.) and those having abundant natural mineral deposits (such as in the Rocky Mountain region)
      2. But Dean and his team couldn’t correlate the observed enamel mottling/discolorations to the existing detectable elements found in the water (e.g., lead or manganese)
      3. However, it was known that the mottled teeth were less susceptible to tooth decay, and by virtue of separate dental research and experience with known levels of fluoride, it was suspected that fluoride might be a factor in the mottling of teeth.
    4. But a good way of measuring unknown concentrations of fluoride wasn’t available, until Elvove, who collaborated extensively with Dean, devised a method to measure low levels of fluoride in the early 1930s.
      1. This allowed correlations to be constructed between fluoride levels and enamel mottling/discoloration. So in theory, with lower fluoride levels, mottling would be reduced as well.
      2. And to test this reasoning, as published for example, by Dean in 1939, once new water wells were drilled (ones with much less natural fluoride), the communities experienced marked reductions in enamel mottling.
    5. Achievements in the 1940s involved building relationships among the level of fluoride in a given water supply, the prevalence of enamel mottling, and the prevalence of tooth decay.
      1. For example, Dean published in 1941 observations on the fluoride content in water supplies of 8 suburban Chicago communities and the level of tooth decay found in over 2,000+ children between ages of 12 and 14
      2. These relationships pointed to a level of fluoride that would give maximum protection against tooth decay while minimizing fluorosis. That level? 1 ppm.
    6. Dean proposed evaluations to see if certain cities manifesting high caries activity might benefit from new water supplies having about 1 ppm fluoride (or, at least less than 2 ppm F).
      1. Dean proposed studies based on baseline fluoridation levels in several cities, including Grand Rapids (Michigan), Newburgh (New York), and Brantford (Ontario), all of which had naturally low levels of fluoride.
      2. And on Jan 25, 1945, Grand Rapids became the first of many cities to utilize artificial water fluoridation set at 1 ppm
  3. Fast-forward to 2015, the US Public Health Service has recommended water fluoridation levels could be set at 0.7 ppm fluoride due to the prevalence of other daily-use fluoride sources
    1. The high clearance of fluoride at low concentrations indicates the build-up of fluorine is highly unlikely coming from properly fluoridated community water supplies. Of course, under no circumstances should fluoride rinses or toothpastes and such be ingested, as the fluoride concentrations of these are much greater.
    2. If there are concerns about fluoride, I would imagine it’s likely due to metallic-fluoride bonding that may be formed in water supplies that have excess lead, copper, nickel, cadmium, zinc, etc).
    3. And while tap water drinking is still fairly common, less people are drinking tap water now than they did 70 years ago due in large part to the availability, convenience, and consumption of bottled water and carbonated drinks are up!
  4. In conclusion, in my opinion, I believe that since it’s introduction nearly 70 years ago, water fluoridation is safe and effective at levels near 1 ppm.
  5. So, thank you for watching this video and if you have questions or comments, please contact me through my website as I look forward to hearing from you. Until the next time, thanks for your attention and goodbye.


2018-03-12T16:39:14+00:002018|Media, Q&A|

Robert L. Karlinsey, PhD

Dr. Robert L. Karlinsey earned a BS in Physics and PhD in Chemical Physics, holds several patents, and has published in multiple fields including dentistry, chemistry, and materials science. His lifelong struggles with his own dental decay ultimately inspired him to investigate the remineralization of teeth.