How was the human race able to survive all these centuries without having extra fluoride being added to the drinking water ?
The human race was doing just fine without extra fluoride in the drinking water, until some genius came along and drew up a bunch of spurious "reasons" for doing it.
One of the things you notice in prehistoric skeletons is the presence of very poor dental health - there are variations and exceptions, depending on time and place, but very often by the time you hit forty, your teeth were likely to be toast.