50 years ago, fluoridation was promoted as a bone protector

Fluoridation lessens disease in adults — Antifluoridationists … not only “have little concern for the preservation of children’s teeth,” but “are contributing to the ill health of all of us, young and old alike,” [said] Dr. D. Mark Hegsted, professor of nutrition at Harvard’s School of Public Health.… [An] adequate intake of fluoride can keep bones healthy and prevent soft tissues from calcifying. — Science News, November 5, 1966

Update 

The role of fluoride in bone health has been much less clear than its benefit for teeth. Studies in the 1980s showed treatment with a calcium-fluoride mix increased bone mass (SN: 1/21/89, p. 36) and reduced fracture risk in women with osteoporosis. But an analysis of 25 studies in 2008 showed fluoride doesn’t ease fracture risk. In 1951, only 3.3 percent of the U.S. population had fluoridated water; by 2014, that rate was up to 66.3 percent. Fluoridated drinking water may not help bones, but it does reduce cavities by 25 percent in both adults and children.