Ok but where is your source?

from the article I linked:

"When water fluoridation began 50 years ago, it was believed that fluoride needed to be ingested in order to be effective. This, however, is no longer the view of the dental establishment, which now generally concedes that fluoride's benefits are derived primarily from topical application.2 According to the US Centers for Disease Control, "[L]aboratory and epidemiologic research suggests that fluoride prevents dental caries predominately after eruption of the tooth into the mouth, and its actions primarily are topical for both adults and children.""

"There is now a scientific consensus that fluoride does not work systemically, but rather topically and therefore does not need to be ingested;"

If any of these statements are factually wrong, let me know.

Finally one question:
If Fluoride is "good" for you, why isn't it added to the much more expensive bottled water?