fluoridation has a tag wiki and has 20 questions, while fluoride lacks a wiki, and has 6 questions. Of the six questions tagged fluoride, all of them are either tagged with fluoridation, or have fluoridation in their title.
Logically speaking, all questions about fluoridation are about fluoride, but not all questions about fluoride are about fluoridation. Doing a search for questions with "fluoride" without either tag, I came across Are cheap tea bags dangerous to your health due to high fluoride levels? , which mentions fluoride but not fluoridation.
There are two questions mentioning fluorine (the name of the chemical element), but neither are primarily about the element.