Hi, we are trying to weaken the idea that Fluoride doesn't help prevent tooth decay, as shown by the fact the teeth are worse in the us (where we use fluoride) than in Eu, there they do not.
The biggest flaw in this argument is that there may be other differences between the two regions. Perhaps Europeans have better dental heath in general and are more likely to floss and brush their teeth. Perhaps they have better diets that lead to better teeth. E strengthens by ruling out the alternative cause of better oral hygiene
