A grown tooth has a fixed structure. See picture. On the outside you find a white hard glossy surface layer. This is the enamel. It is mineralised for 96%. Underneath this enamel you find the tooth bone or Dentin. This is mineralize for 70%. And further inside you find a space containing blood vessels and nerves forming the so called pulp. Take note that the blood vessels and nerves do not reach into the enamel. So, any ingested fluoride cannot get via the blood stream to the enamel. Therefore ingesting fluoride to protect your teeth from decay is useless.
Graphic from: http://upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Tooth_Section.svg/496px-
Tubules
The dentin contains thousands of tiny canals or tubules, which allow fluid and nutrients from the pulp to reach the dentin throughout. These tubules are running from the pulp with a wavy S-form to the dentin/enamel boundary. Through this tubular structure filled with fluid the dentin gets some flexibility and resilience. The tubules are wide near the pulp and taper to very narrow towards the enamel and end there as dead end streets near the boundary line dentin/enamel. They have also numerous little side branches and some of them interconnect the tubules. This arrangement forms a gigantic mineralised inner surface paved with calcium phosphate in the hydroxy-apatite form. Any fluoride getting into these tubules would immediately react with the calcium and change hydroxy-apatite into fluoro-apatite, which is much more brittle.
In the 1950s and 1960s research was done to see whether fluoride intake would have an effect on the inside of teeth. It turned out that fluoride was indeed deposited in the dentin. The highest fluoride concentration was found in the wider section of the tubules near the pulp. This indicated that the fluoride came from the pulp blood supply. It was also found that when the tooth ages, the tubules were filled in with a hydroxy-apatite material and became calcified. The presence of fluoride accelerated this deposition. The overall effect was that the dentin became hard and brittle and structurally weak.
Dean Murphy DDS. 2008. The Devil's Poison - How fluoride is killing you. pp. 64 and 62. Trafford Publishing www.trafford.com/07-1894
This change in chemical structure can cause problems in later dental work as was reported in 1940 by two dentists 'The Smiths' from Arizona:
At that time St David in Arizona had a fluoride content in drinking water of 1.6 to 4 ppm. They observed that:
"Steps taken to repair the cavities in many cases were unsuccessful, the tooth breaking away when attempts were made to anchor the fillings, so that extraction was the only course. That decay was widespread and repair highly unsuccessful among young adults was shown by an incidence of more than 50 percent of false teeth in the age group 24 to 26 years. Very rarely, adults were found whose teeth, though mottled, were free from caries."
G.L. Waldbott et al. 1978. Fluoridation: the great dilemma, chapter 12, pp. 175-177. Coronado Press, Inc. Lawrence, Kansas.
Given the fact that now in the US fluoridation can occur up to 4 ppm, this result is a triumph of modern dentistry. Imagine at 24 to 26 years of age more than 50% of young adults without any decay due to fluoridation (and without teeth).
Mottled teeth.
Mottling of teeth (dental fluorosis) happens before tooth eruption into the mouth takes place. At that stage the enamel forming cells (ameloblasts) through their own blood supply are poisoned by the ingested fluoride and produce a botched enamel. After tooth eruption these enamel forming cells disappear including their blood supply and you are left with the enamel as formed. Once you have mottled teeth you have it for life. Mottled teeth are under-mineralised with a porous, brittle enamel. Dental fluorosis is the clinical symptom of chronic fluoride poisoning during tooth formation.
However, in the textbooks on dentistry the issue of mottled teeth is dismissed as merely 'cosmetic.' In those textbooks any indication that fluoride is a very powerful poison is left out. This amounts to gross misinformation of dental students. So, any time a dentist comes across mottled teeth it does not register as a poisoning symptom and the fiction is maintained that fluoride is harmless. Take note, mottled teeth also indicate possible damage to bones, thyroid and brains as fluoride accumulates there as well. More than 80% of ingested fluoride is retained in children.
A new fake theory in the make?
A number of times I came across the assertion that enamel functioned as a selective permeable membrane and would let water through and certain ions. So, water and ions would 'bleed' through your teeth to the outer surface of the enamel. However, there is no research to that effect. The next step in this theory making would be of course to claim that fluoride was one of these ions. This, however, overlooks the fact that for a membrane to be selective permeable, it must be inert to the substances that move through the membrane. In case of fluoride it would be immediately attracted to the calcium in the enamel. So, if fluoride would ever reach the enamel, it would be chemically bound by the calcium at the borderline dentin/enamel.
This trial theory is a tacit admission that ingested fluoride does not reach the outer surface of the enamel. As stated before ingested fluoride does not protect against dental decay and therefore it is useless to ingest fluoride.
