A simpler alternative is xylitol. Not a drug, no FDA approval required. It's a plant-based sweetener that cavity-causing mouth bacteria love to ingest, but which provides no sustenance to them. It essentially fills them up and then causes them to starve them to death, helping maintain minimum mouth bacteria. No bacteria, no cavities. Get it in mints or gum like Zellies or PUR (the only two I've found that don't include Titanium Dioxide). Take one a day after brushing in the evening so it kills bacteria overnight.
https://zellies.com/
https://thepurcompany.com/
https://www.healthline.com/nutrition/xylitol-101
(Also if you have pets, make sure they don't get any, xylitol isn't good for them, especially dogs)