Posted by Larry Hoover on September 27, 2003, at 12:39:39
In reply to Re: Fluoride » mattdds, posted by tealady on September 27, 2003, at 0:15:34
> > Reality is that the only disease that changes is dental caries, and quite obviously for the better.I wouldn't be too sure of that. Methinks you may have "dental student credulity disorder". <grin>
Here's one accessible article:
http://www.tldp.com/issue/157-8/157fluor.htm> Yes there is an admittedly a decrease in dental caries, but a far more significant decrease is just occuring with time..perhaps from school clinics which have been introduced gradually in the past 30 years?
And dental caries are in substantial decline in Europe, where fluoridation is virtually unknown.
> "Dental decay rates have been falling for three decades in both fluoridated and unfluoridated communities. "
> http://www.fluoride-journal.com/98-31-4/314-232.htm
> > Right. 1 ppm in drinking water is the level determined to have the most benefits with fewest adverse effects.
>
> Well ours is stated as 0.9 - 1.5 mg/L. I do not know how this converts to ppm.Same thing. Given that the mass of one litre of water is 1,000 grams (by definition), the ratio is convertible via: mg/1000 g, which is the same as 1g/1,000,000 g, or part per million by mass.
About fluoride and caries, the evidence isn't always pro-fluoride:
Quintessence Int. 2003 May;34(5):354-60.
Dental caries and fluorosis in low- and high-fluoride areas in Turkey.
Ermis RB, Koray F, Akdeniz BG.
Department of Restorative Dentistry and Endodontics, School of Dentistry, Suleyman Demirel University, Isparta, Turkey. banu_ermis@yahoo.com
OBJECTIVE: The aim of this study was to investigate the caries prevalence of children living in either low- or high-fluoride areas and to relate caries experience to the severity of dental fluorosis. METHOD AND MATERIALS: A total of 278 12- to 14-year-old schoolchildren, 149 in a low-fluoride area (LFA) and 129 in a high-fluoride area (HFA), were included in the study. The naturally occurring fluoride concentrations in the drinking water were 0.30 to 0.40 ppm in the LFA, 1.42 to 1.54 ppm in the HFA1, and 1.55 to 1.66 ppm in the HFA2. Dental caries was recorded with the World Health Organization criteria, and dental fluorosis was measured using the Tooth Surface Index of Fluorosis. RESULTS: The percentages of children who had an average TSIF > or = 1 were 0%, 29%, and 77% in the LFA, HFA1, and HFA2, respectively. The mean decayed, missing, and filled permanent teeth (DMFT) and decayed, missing, and filled permanent surfaces (DMFS) were 0.84 +/- 0.98 and 1.58 +/- 2.24 in LFA, 1.30 +/- 1.46 and 1.78 +/- 2.52 in HFA1, and 1.26 +/- 1.42 and 1.97 +/- 2.60 in HFA2, respectively. There was no significant difference in caries prevalence among children living in low- and high-fluoride areas when evaluated with an analysis of covariance model, including the frequency of toothbrushing. Toothbrushing frequency had a significant effect on the decayed teeth, decayed surfaces, DMFT, and DMFS. In high-fluoride areas, there was no relationship between caries prevalence and severity of fluorosis. CONCLUSION: Increasing water fluoride levels were associated with higher prevalence and severity of dental fluorosis and had no influence on caries experience in children with poor oral hygiene.
The article link, above, has some arguments presented which are due, at least, for consideration.The link between thyroid hypofunction and fluoride exposure is quite firm in humans, but most of the evidence has been presented in papers in Russian and Chinese. Rodents appear to be immune to fluorine/thyroid toxicity, but we're not rodents. Cows can't handle fluorine, just as a comparison.
What underlies the "1 ppm fluoride is safe" argument appears to be the idea that there is a toxic threshold, below which there is no adverse effect. That, however, is not true. The toxic effect is continuous, and variable in different populations exposed to the same dose. Looking at whole-population parameters will not reveal the effect on thyroid function in susceptible individuals, because it is a rather rare effect. But the incidence of thyroid toxicity at 1 ppm fluoride is not zero. As there are so many variables which affect thyroid function, finding unequivocal evidence is probably not possible. Dismissing the link altogether requires acceptance of the null hypothesis, and I'm not willing to do that.
Lar
poster:Larry Hoover
thread:263511
URL: http://www.dr-bob.org/babble/20030923/msgs/263737.html