Going on the assumption that you are a dentist which I am willing to do, although anyone can safely claim almost anything on an anonymous web forum, I won't attempt to argue with a highly trained professional on matters concerning his or her field of expertise.
However, I do want to mention that there are a considerable number of dentists both in the US and elsewhere who would dispute at least some of your claims for the benefits of fluoride in public water systems. As I mentioned earlier in this thread, a recent president of the Canadian Dental Association, or whatever the exact name of the organization is, resigned his position because he felt that he could not in good conscience continue to support the organization's commitment to fluoridation of public water systems. In his statement, which I read but did not bookmark, he cited specific data compiled by well qualified research scientists that supports the proposition that fluoridation of public water systems causes more harm than good in the long run.
If as you say my age exempts me from the undesirable side affects of fluoride on my teeth because it was not in the water I drank during my youth, then I will take your word as a dentist that what you say is true. But my dental record is not relevant to the study that came to the conclusion that fluoride in drinking water is an important causative factor in the increasing percentage of elderly patients who are afflicted with osteoporosis. I would also point out that the Canadian dentist who voiced his opposition to the fluoridation of public water systems did not mention fluoride as a cause for brittle or weakened teeth. His criticism was confined to the widespread use of fluoride as it relates to the rapidly rising rate of osteoporosis in the elderly population, which I think you would agree is a much more serious matter than brittle teeth.
Fluoride, in high doses, has its negatives. Heck, water in high doses has its negatives. But at 0.8 to 1.2 ppm, fluoride’s negatives are greatly outweighed by the positives.
The need to fluoridate water is probably not needed as much today because fluoride is available in so many other forms (toothpastes, rinses, supplements, etc). However, epidemiological studies seem to indicate that the relatively recent increase we’re seeing in children’s caries rates may be partially due to the fact that so many people are now consuming bottled, unfluoridated water.
One thing I can assure you of is that fluoride (in acceptable levels) doesn’t cause brittle teeth...but it *does* make teeth more impervious to tooth decay. Your concerns about osteoporosis may or may not be valid. I haven’t read up on that. But geriatric patients do see a higher incidence of root surface caries as their gums recede, and fluoride can help prevent that.
As with anything, weigh the risks vs. the benefits, and I think you’ll see that the benefits outweigh the risks.
But since I believe in personal responsibility and autonomy, I agree that in a perfect world where everybody attends the dentist (and actually follows the advice of their dentist) the water supply should not be fluoridated. But we’re stuck in an imperfect world where misinformation makes people believe that fluoride makes their teeth brittle...so they avoid it.