The top graph clearly suggests that more kids get straighter teeth growing up in higher fluoride areas. The bottom graph just shows how much fluoride a person would get by drinking the water. We just don't know much more than that about dosage. The point is that a normal dose for a young woman (1 mg F) is in the ballpark.

For the moment let's assume that a reasonable dose of fluoride causes straighter teeth. Next is the tricky question of WHEN does fluoride have the presumed effect.

The reason I think this effect is from early pregnancy is biological. The shape of the jaw, which most logically makes the most difference between straight and crooked teeth, is set very early in pregnancy and has almost nothing to do with heredity. (The spacing of teeth can be seen by the 11th week of pregnancy. Garn 1979, Journal of Dental Research 58(2):554.) Whenever the spacing is set, it is before prenatal fluoride is started (about the third month, when teeth start forming). Prenatal fluoride does not do anything (or at least not much) to prevent crooked teeth. Here is a little tale about that. 

When I started doing some fairly serious reading about prenatal fluoride, I ran into something that was a little spooky. A report* by Dr. Glenn made me wonder if prenatal fluoride somehow caused kids to need braces.

The main point of this report is that dentists can get more business from less cavities.   Dr. Glenn found that her prenatal fluoride patients (the ones with no cavities at all) actually gave her more business. The cavity-free children spent $338 per year per person, versus $234 per year for the children with cavities. It is interesting that Dr. Glenn found this spending difference even in the same family, where one child would have cavities and the other would not.

There is no further spending breakdown, but it is implied that the parents are so impressed with the beautiful and cavity-free teeth that they are far more willing to spend big bucks on orthodontics. (I do not have an exact figure, but local dentists tell me a set of braces costs about $2,000. This cost is generally not insured.)

You can find a small confirmation that parents put more braces on cavity-free kids in a trial of infant fluoride by Aasenden**. In the second [1978] trial, when the children are about 15 years old, the subject of braces comes up. There were so many more cases of braces in the fluoride group than in the controls that the authors were concerned about whether the control group was actually a good comparison.

When I started wondering about the possibility that fluoride caused the need for braces, I wrote to Dr. Glenn. He [Darby] assured me that it really was a simple matter of the parents' willingness to pay for the treatment. Prenatal fluoride made absolutely no difference in the need for braces. Both groups -cavities or not - needed them equally. Prenatal fluoride creates beautiful individual teeth, but it does nothing for the way those teeth are arranged in the mouth.

Now let's stray deep into ancient history. This is a pretty obscure area of fluoride research, but I love it. In a nutshell, our ancestors, the earliest hunters and gatherers, had fluoride intakes vastly greater than we do today. And they had, among other things, very straight teeth. It will take me a while to put it all together.

Fluoride is usually in the rougher-tougher parts of foods. For an extreme example, the whole grain that cows eat has about 100 times the fluoride of the bread that we eat***. The same is true between their pasture grass and our vegetables like broccoli. Many foods are of course the same (an apple is an apple, gathered or bought). In total, a reasonable estimate is that hunters and gatherers got about 5 times the fluoride of modern people.

I always think of hunters and gatherers as eating more small whole animals (complete with bones, shells, scales, teeth, etc.) or big animals with their bone marrow. And lots more greens, which are the easiest and most consistent food you can find. These foods aren't super-rich in fluoride, but typical of the food chain. In modern foods many of the replacements are low and approaching zero: muscle meat, iceberg lettuce, sugar, etc.

Some early peoples got more fluoride than others. There was at least one group of hunters and gatherers who got enough fluoride to cause fluorosis. This was in the South Pacific, in the Austral Islands. "The inhabitants of the Australes and Savaii continue to eat traditional Polynesian food. From this, particularly fish, taro root, and coconut, they absorb sufficient dietary fluorides to produce slight mottling of their permanent teeth. A recent survey (1970) of the school age population of the Australes showed an incidence of 90% of mild white flecked fluorosis and of 6% moderate brown flecked fluorosis." The author was also comparing the teeth of the natural-living islanders to the teeth of Tahitians who had a more modern diet. The saddest of the modern cases was a bevy of otherwise beautiful teenaged girls who had no teeth left at all.

(The source is Baume, 1970. Arch Oral Biol 15:431; and Indent 1(3):36. The water fluoride level in the Australes was .5 ppm. That is fairly high relative to most easy-to-get water. Artificially fluoridated water is usually 1 ppm. If the water fluoride is much higher than 1 ppm, it starts causing fluorosis. See any book on fluoride for more details on water fluoride. Another way they would have gotten higher than average fluoride would be the use of sea salt. Sea water is about like fluoridated water in F content, about 1 PPM. I haven't worked out the numbers, but sea salt would be fairly high in F. To eat the greens of the taro plant - a very common and tasty Polynesian food - you have to cook them in salty water.)

A common misconception is that if we were hunters and gatherers we would die by about age 30 because our teeth would rot out. Nothing could be farther from the truth. Almost any book on anthropology will tell you that it was hard to find so much as a trace of decay before agriculture was adopted****. In fact, that is how they tell that people had started farming - their teeth started showing small areas with weak enamel called enamel defects, and traces of decay. Even with primitive agriculture, many groups still had almost zero decay. This was especially true if they lived near the sea (seafood is very rich in fluoride).

The other thing primitive people did not have was what we call "malocclusion", or crooked teeth. Burials have been found with thousands of skulls with not a single tooth out of line.

There is a book that thoroughly tells the story of how people's teeth changed when their diets changed from primitive to modern. It is called Nutrition and Physical Degeneration*****, by Weston A. Price, DDS. There are striking photographs and lots of details. The interesting thing is that the changes happened not so much to the first people to eat modern food, but to their children who were conceived, born, and raised on it. The older generation, even the very oldest, had fine sets of teeth. The children had both rampant dental caries and crooked teeth.

By a quirk of fate there is also a story about a group of people whose diets changed the other way. A group of modern settlers got stranded on an island, Tristan da Cunha, for a few decades when shipping routes changed. When they were found their children had near-perfect teeth. Increased fluoride in their diet was given the credit. (Sognnaes 1941, Journal of Dental Research  20:16.) When they once again returned to modern foods, the new kids born had rotten teeth. (Rosevear 1993, PPNF Nutrition Journal  17(1):12.)

In summary, the "proof" that fluoride causes straight teeth (or that the lack of it causes crooked teeth) is what we have seen above. That in modern areas with higher than average fluoride in the water a lower percentage of kids have crooked teeth. And the ancients that ate high fluoride foods had perfectly straight teeth, and as soon as they changed diets their kids got both cavities and crooked teeth.

In a sense, the most dramatic difference between prenatal fluoride kids and hunters and gatherers is the shape of the jaw. Both groups have zero cavities, but the prenatal fluoride kids do not have the perfectly straight teeth seen in the hunters and gatherers. The big difference in these two groups is when they start their fluoride. The only fluoride the prenatal fluoride kids did not get was the fluoride in the first few months of pregnancy. That timing lines up perfectly with the time the teeth are arranged in the jawbones.

We will get to dosage later, but I think that something about like doses used for normal adults and in the early trials of prenatal fluoride (1 mg F per day) would probably be enough to get this "perfectly straight teeth" effect. It would ideally be started before pregnancy. Fluoride is, of course, just a small part of early pregnancy nutrition.

As far as what to look for, I can give you an almost poetic quotation. An early popular nutrition writer, Addelle Davis, really had the vision as far as the importance of early pregnancy nutrition and the shape of the mouth. Note how easy she makes it to understand what to look for in a newborn's mouth: "The ideal dental arch, or the jawbone holding the teeth, should be almost a perfect semicircle; there is plenty of room in such a mouth for all the teeth without crowding. The dental arch should not be the shape of a tall U and certainly not V-shaped, as many are. The roof of the mouth, or dental vault, should be low and rounded like the roof of a Quonset hut, not like that of a high Swiss chalet built so that snows slide off quickly." (From her 1972 book that emphasizes folic acid in early pregnancy, 20 years ahead of organized medicine. She didn't quite get into fluoride.)

References and notes from above:

*The Glenn report is in French:  Dental Income and Prenatal Fluoride / Glenn FB, 1983.  La Prevention Bucco-Dentaire 13:27 [Jan-Mar]. I could not find this article using normal sources, and got mine, a translation, from the Glenn's foundation.

**Aasenden R, Peebles TC. Effects of fluoride supplementation from birth on human deciduous and permanent teeth. Arch Oral Biol 1974; 19:321 and 1978; 23:111. These reports are by far and away the best of early trials of pediatric fluoride.

***

**** Sources for the idea that hunters and gatherers had no cavities to speak of:  Sealy JC; Patrick MK; Morriss AG; Alder D. Diet and dental caries among later stone age inhabitants of the Cape Province, South Africa. Am J Phys Anthropol 1992 Jun;88(2):123-34. (Zero caries in one group, 17.7%[= "extremely high"] in another. Fluoride in ground water given the credit, but also fluoride in seafood.) Cohen MK. Health and the rise of civilization. Yale Univ Press 1989. Caries came with ag (pg 107): "Rates of caries go up so uniformly with the adoption of agriculture that several scholars have inferred agricultural diets from high caries rates in the absence of confirming food refuse (cites)". Ditto enamel defects: "They [enamel hypoplasias and microscopic enamel defects] are almost invariably reported to have become more frequent and/or more severe as farming replaced hunting and gathering... (cites)".

***** You can find Price's books in many libraries, certainly medical ones. Another more recent source with a few of Price's pictures is Schmid RF. Traditional foods are your best medicine Ballantine Books 1987. (The main point of this book is the lack of caries and malocclusion from traditional foods, and the staggering changes that occurred as soon as people shifted to white flour, sugar, etc. All of these foods are very low in fluoride, but this book doesn't touch that connection.)