I take it you mean Fluoride. The answer is generally no. Most people do fine with it, and the risk of being poisoned in the long term from fillings and root-canals is probably bigger than the risk of long term fluoride poisoning.
If you want to use Flour on the other hand the answer is Yes
To be more specific fluoride need is individual.
Some people lack the caries causing bacteria S.mutans in their oral cavities and those people really don't need much extra cavity protection.
Though they might need protection for their overall enamel-situation if they consume an erosive diet (soft drinks, wine, candy, the performance of endurance sports).
If you lack S.mutans or if you maintain a diet with evolutionary adapted intervals (i.e two or three meals a day, no sugary drinks in between, even a sip of coca cola counts as a full meal) between meals you can do without fluoride.
That is provided you clean every surface of the teeth properly, i.e. electric brush and proper flossing technique. Preferably test your plaque-removal using staining pills from the pharmacy.
Leaving food and detritus accumulated in the approximal or occlusal areas will be a constant supply of food for the S.mutans.