I chanced to read a news article about fluoridation (Sun colour supplement from the 1950s) that was timed after fluoridation was introduced in America before it was introduced in Australia. I followed that with a chat with my 96 year old father in law who had actually visited a fluoridation plant many years ago.
It’s rather chastening that it taught me heaps about fluoridation that I never knew before. And opens up a heap more questions.
I already knew that fluoride reacts with the soft hydroxyapatite in tooth enamel to make the more resistant fluorapatite. I already knew that too much fluoride caused teeth mottling and cracking. I already knew that drinking water and toothpaste contains fluoride. I already knew that off-the-shelf after-tap water filters remove some but not all of the fluoride. I knew that my daughter’s teeth at a young age were very much worse than mine were, almost as bad as my wife’s (I grew up in a fluoridated water location. My wife didn’t, she only had fluoride pills and her teeth were much worse than mine). But that’s about the sum of my previous knowledge.
The news article told me that fluoride at a dosage of 0.88 (can’t remember units) in American water supplies cut teeth decay in children under 10 by a factor of three, and further fluoride cut decay a bit more. It told me that this was based on occurrences of natural calcium fluoride found in American water supplies. It said that a study suggested that sodium fluoride was even better than calcium fluoride. It said that the dosage that could be added to toothpaste would be much higher than for water because it wasn’t swallowed, suggesting a higher toxicity for swallowed fluoride. It said that fluoride also acted as an antibiotic, killing the lactobacillus that causes tooth decay. It said that fluoride caused mottling of teeth but didn’t mention cracking, which suggests that the mottling is only a cosmetic problem and occurs at lower water fluoride concentration so serves as an early warning system.
I surmised that the calcium fluoride came from water that had dissolved salts from limestone.
My 96 year old told me that sodium fluoride greatly outperforms calcium fluoride because it is more soluble. Calcium fluoride is only sparingly soluble. But the fluoride added at the fluoridation pant was not sodium fluoride but sodium hexafluoride, formula Na2F6. He said that sodium fluoride was made in the Tomago aluminium smelter by mixing seawater with the product. He said that fluorosilicate had been suggested as a replacement for sodium fluoride/hexafluoride, but he had never seen a study that showed that fluorosilicate was effective. He said that the effectiveness of fluoride was discovered when dentists noted spotting of teeth in certain towns of western USA, and found that the effect depended on location and was independent of race and diet. He said that spotting starts to occur at a concentration of about 2 parts per million. He said that the fluoride was added by diverting a small percentage of the water in a pipeline through a chute into which sodium hexafluoride powder was dropped, before being returned to the main pipeline to complete the mixing. He didn’t say when he visited this plant, but it was when he was “young”, more than 50 years ago.
But that leads to a whole heap of questions.
1. Calcium fluoride vs sodium fluoride vs sodium hexafluoride vs fluorosilicate. How do they compare in effectiveness? Which is used to dose water?
2. I got the impression that that 0.88 was about 8.8 parts per billion, which is about a 200th of the amount that causes spotting of teeth. Is that correct? What is the current dosage used when fluoride is added to water and how much less is that than the dosage that causes minimal dental problems? What is the dosage in toothpaste?
3. All fluoride toothpastes are very strongly flavoured. What is the flavour of calcium fluoride vs sodium fluoride vs sodium hexafluoride vs fluorosilicate and which is added to toothpaste? Is it a strong flavour?
4. Which mineral water / soft drinks contain sufficient fluoride?
5. What is the toxicity of fluoride in water as it relates to bodily organs other than teeth?
