Is it a coincidence that none of the following countries have fluoridation of their water supplies?

North Korea, Iran, Armenia, Ukraine, Northern Ireland

Sauces(need to be bolstered):

https://www.waterlogic.com/en-gb/resources/whats-in-my-tap-water/how-to-remove-fluoride-from-water/

https://en.wikipedia.org/wiki/Fluoridation_by_country