Is it true that flouride can cause weak bones?

Sort of: Floride taken in medicinal form (large doses taken in orally) will make bones more dense, but actually more likely to fracture. The amount that is ingested just brushing your teeth or using a mouth rinse is not enough to have a significant effect, especially if you spit them out and rinse afterwards as directed. The beneficial effect of floride for your teeth is significant.

No.: It's the lack of Fluoride that causes not just weak bones but is responsible for causing increased number of cavities due to weak teeth. With water fluoridation, we see 50% less cavities. Fluoride occurs naturally in the body as calcium Fluoride and helps maintain bone structure. Low doses of Fluoride salts may be used to treat conditions thatcause faster-than-normal bone loss, such as menopause.

Fluoride: Too much of a good thing can be bad!

Thick but Brittle?: Most current juried scientific literature says the opposite: Fluoride can be taken to add bone thickness. However, if is possible that thick bones may be more brittle. Bottom line, i wouldn't go out of my way to ingest the stuff by eating toothpaste with Fluoride nor would i avoid drinking fluoridated municipal water.

Depends: Like many things, the proper amount of a strong thing can help while too much can hurt.It is the same with most drugs/anesthesia,etc. We know a small amount of fluoride added to the drinking water will harden the enamel and reduce tooth decay, while an excess can cause a condition called fluorosis, where the teeth (and bones) are stained and brittle'