Ask Tufts Experts July 2015 Issue
Q. My dentist recommended using a prescription fluoride toothpaste. If the water in my city is already fluoridated, does that contribute to the risk of possible overdose?
A. Public Health Dentist Wanda Wright, DDS, and Associate Clinical Professor David Leader, DMD, posed this question to Tufts University School of Dental Medicine Dental/Public Health students. Their short answer is that using prescription fluoride toothpaste in communities with water fluoridated at the usual 0.7 to 1.0 parts per million (PPM) will not contribute to the risk of an overdose.
They explain, “Fluoride reaches a toxic level only at 2.5 to 5 grams per kilogram (2.2 pounds) when consumed within two to four hours. That means that an adult would have to ingest hundreds of gallons of community-fluoridated water within a few hours to cause harm. If you were to try to drink that much water so quickly, you would die from the effect of the water before the fluoride could reach a toxic level. It is very important to note the two- to four-hour time frame. Consuming less fluoride over time does not create an additive effect.
“How much water is a toxic dose? In 2007, a 28-year-old woman died after swallowing only 6 liters (6.34 quarts) of water in a contest. That water might have contained 6 milligrams of fluoride. The additional fluoride of prescription toothpaste, if you were to swallow all of the prescription toothpaste on a toothbrush, might be as high as 2 milligrams per use. That means that if this woman also used prescription fluoride toothpaste in that time, she may have ingested as much as 8 milligrams of fluoride in 24 hours. That is a small percentage of an acutely toxic dose for an adult. Please note that we do not recommend prescription fluoride toothpaste for children under seven years old.”
Misleading answer, an overdose no but long term harm like fluorosis yes.
posted by Bill at
9:58 AM
3 Comments:
"Misleading answer"?
No. Dental fluorosis can only occur during the teeth developing years of 0-8. Skeletal fluorosis is so rare in the 74.6% fluoridated US as to be nearly non-existent. The US Institute of Medicine established daily upper intake of fluoride before skeletal fluorosis or any other adverse effct may occur, is 10 mg.
Steven D. Slott, DDS
By
Steve Slott, at 27 June, 2015
Steven, nice to have you back! :-)
I have to tell you, though, that there is a multitude of sin hidden behind your simple quotation of a statistic. Take your "everything is hunky-dory if you consume less that 10mg per day" figure.
1. That "upper intake" limit for babies is not 10mg/day of course. It is actually 0.7 - going as high as 2.2mg/d for 4 - 8 yrs.
2. Bear in mind this is the upper "tolerable" intake (U.T.I.) - above which, presumably, it would not be tolerable?? Not for anybody. You seem not to want to use that qualifying word "tolerable". Why not?
3. This U.T.I. applies to "almost all individuals in the population" according to the Institute. No idea then of who it does NOT apply to? Or the harm that might be done? I would imagine people with pre-existing medical conditions, particularly kidney malfunction, were most at risk. How many people is this? What harm may occur to them? Will any die - or live shorter lives - as a result? How do we protect them?
4. Yet this U.T.I. becomes meaningless when set aside the Recommended Daily Allowance (RDA) because there is NO RDA (apparently not enough research!). Makes you wonder how they managed to get the U.T.L. figures! Instead they give what they call an "Adequate Intake" (A.I.) figure (they admit this figure is not much better than a guess and do not know how many people this A.I. might apply to). This A.I. varies between 2 - 4 mg/d for (healthy!) adults to the much lower levels for children, to as near as dammit zero for babies. Not forgetting that water fluoridation is being sold to us as helping children's teeth - children seem to have a much lower tolerance for this poison. Natural mother's milk also uniquely filters out the fluoride from the body - showing that perhaps breast-feeding is really best?
5. However the real damnation of this 10mg U.T.I. figure lies in the source - which is dated 1997! 18 years ago!! There's been a lot of research in those intervening years virtually without exception showing fluoride to be more dangerous than previously believed.
So, you see Steven, your reassuringly glib assertion about a 10mg "Upper Limit" is more deceptive than clarifying. As is your comment reference "skeletal fluorosis". Younger and younger people nowadays are being diagnosed with "arthritis" which is almost identical to skeletal fluorosis. Doctors are not trained to recognise anything but the severest forms of skeletal fluorosis and, until that point, invariable will diagnose arthritis instead. Maybe it's the skeletal fluorosis diagnosis that is rare, rather than the condition??
Regardless, I guess you'll continue to use those same 10mg/d ("upper intake" - nothing about "tolerable"!) figures on other forums. But you will now know that on this forum at least we won't have the wool pulled over our eyes with seriously misleading statistics.
By
Unknown, at 28 June, 2015
Chris
1. The IOM daily upper limit for infants:
0-6 mos -0.7 mg.
6-12 mos - 0.9 mg
1-3 years- 1.2 mg
4-8 yrs- 2.3 mg
Above 8 yrs- 10 mg
The only risk to infants and children 0-8 years from exceeding this upper limit due to optimally fluoridated water, is mild to very mild dental fluorisis, a barely detectible effect which causes no adversity on cosmetic, form, function, or health of teeth.
That mild dental fluorosis is the only risk to infants is evidenced by the fact that after age 8, the daily UL jumps to 10 mg . Dental fluorosis can only occur during the teeth developing years of 0-8.
The validity of the IOM daily UL is evidenced by the fact that in the 70 year hustory of fluoridation, there have been no proven adverse effects.
Your unsubstantiated speculation and personal opinions are meaningless. If you have any valid, peer-reviewed scientific evidence of any adverse effects of optimal level fluoride.....including to patients with "pre-existing, conditions, particularly kidney malfunction".....then present it, properly cited.
As no such evidence exists, I will not hold my breath in anticipation.
Steven D. Slott, DDS
By
Steve Slott, at 28 June, 2015
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