Add naturally occurring fluoride like in green tea
Plus fluoride in toothpaste.
And a little fluoride gel which your dentist puts on your teeth
Also no account is taken for individual tolerance
So one can see the dosage could possibly exceed the 1.5 mg "safe" limit
Like aluminium, fluoride has no benefit to the human body and is toxic in any appreciable amount
https://ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/completed/fluoride
