You can buy fluoride that you can treat yourself with as a separate thing. You don't have to do it very often. https://www.amazon.com/Gel-Kam-Flouride-Preventative-Treatment-Flavor/dp/B0013TTR4M
I cannot stand mint because it burns the underside on my tongue so I use non fluoride toothpaste [or even just baking soda] each day with whatever flavor I want.
Dentist. Mine will sell the Fluoridex variety to his patients for $15 a tube. (not covered under my medical or dental insurance but YMMV)
Alternatively, available OTC (less fluoride ppm to stay within legal limits)- something like Colgate Gel-Kam or 3M Omni gel. I use the 3M variety because the grape flavor is a nice changeup from all the mintiness dental products are.