http://www.digitaljournal.com/life/health/reviewing-fluoridation-50-years-on/article/480338

Has fluoride in water helped our health overall?

Posted Nov 24, 2016 by Tim Sandle
Some fifty years ago, in the U.S., consideration was given to adding fluoride to water and toothpaste. This was on the basis of medical advice. Was this advice correct and has fluoridation produced health benefits?
Water from the tap
Water from the tap
CDC
Back in 1966 the magazine Science contained a report from Dr. D. Mark Hegsted that explained fluoridation lessens disease in adults. Those against the introduction of fluoride, the so-called antifluoridationists were called out as having “little concern for the preservation of children’s teeth,” and were instead “are contributing to the ill health of all of us, young and old alike.”
At the time, Dr. Hegsted was professor of nutrition at Harvard’s School of Public Health. The medic led the case that an adequate intake of fluoride can help to keep bones healthy and prevent soft tissues from calcifying.
This sparked the introduction of fluoride in many areas. In 1951, only 3.3 percent of U.S. population had fluoridated water. This figure stands just under 70 percent today. Fluoridated water has fluoride at a level that is effective for preventing cavities; this can occur naturally or by adding fluoride. At the time of its introduction, there was some public opposition the adding of chemicals to water. While public opinion has shifted much further there remains a minority opposition against fluoridation.
In reality  according to Connett   the evidence of benefits is very weak.  Most countries do not flu...
In reality, according to Connett, "the evidence of benefits is very weak." Most countries do not fluoridate water, he said, although he admitted some fluoridate table salt.
Following the phased introduction to most areas, the U.S. Centers for Disease Control and Prevention lists water fluoridation as one of the ten great public health achievements of the 20th century in the U.S. With the introduction of fluoride to water in many states, how has this medical claim held out? Science magazine has revisited the evidence.
The new assessment indicates that the role of fluoride in bone health is considerably less clear than the benefit to teeth. Here studies, dating from the 1980s, indicate that treatment with a calcium-fluoride mix increases bone mass and also reduces fracture risk in women who suffer with osteoporosis. Later studies, reviewing meta-data (the totality of various other studies), conducted in 2008 suggest that rates of fracture are not reduced (see: “Effects of treatment with fluoride on bone mineral density and fracture risk: a meta-analysis”, published in the journal Osteoporosis.)
However, in relation to tooth decay, the evidence suggests that fluoridated drinking water reduces the rate of cavities by 25 percent (a figure applicable to both adults and children.) This is because fluoride exerts its major effect by interfering with the demineralization mechanism of tooth decay. As well as water containing fluoride, the same data suggests brushing teeth thoroughly with fluoride toothpaste is also an effective ways of preventing tooth decay.