You can always use examine.com to start base level research on most substances. It tries to cover the most common questions and link the research papers most relevant to that question if available. Excerpt below, but I recommend scrolling through the whole page. It also discusses maximum safe daily levels, toxic levels, and symptoms when you exceed those levels.
Fluoride (from drinking water, supplements, tea, or dental products) is absorbed by the small intestine, and about half is excreted via the kidneys. Absorbed fluoride in the blood can bind with apatite in bone and teeth, becoming fluorapatite. Blood and bone concentrations of fluoride are in equilibrium and are impacted by bone remodeling activity and age.
Any respectable engineering firm now has a quality control process where a completely different engineer from the designer of record reviews final plans or any major change orders.