Also, even if it is beneficial, which I do not think is true, it doesn’t need to be added to water to help teeth. It’s in most toothpaste and should be a topical treatment, not ingested.
The combination of flouridated water, tooth paste, and other sources, etc can lead to levels that can cause problems, but it's not as simple as "fluoridated water bad".
"The NTP monograph concluded, with moderate confidence, that higher levels of fluoride exposure, such as drinking water containing more than 1.5 milligrams of fluoride per liter, are associated with lower IQ in children. "
So maybe not exactly "water fluoridation cost a few IQ points" in a broad sense, but close enough.
> such as drinking water containing more than 1.5 milligrams of fluoride per liter
> The PHS panel that provided the recommendation considered all sources of fluoride intake and recommended 0.7 mg/L as the concentration that maximizes fluoride's oral health benefits while minimizing potential harms, such as dental fluorosis.
1.5mg/L was where effects could possibly start to be detected. That's over twice the recommended concentrations.
> It is important to note that there were insufficient data to determine if the low fluoride level of 0.7 mg/L currently recommended for U.S. community water supplies has a negative effect on children’s IQ.
“ It is important to note that there were insufficient data to determine if the low fluoride level of 0.7 mg/L currently recommended for U.S. community water supplies has a negative effect on children’s IQ.”