There's a probiotic that aims to prevent cavities forever by replacing your mouth microbiome with harmless bacteria that outcompetes the harmful bacteria. https://www.luminaprobiotic.com/ I'm temped to try it. But I'm waiting for others to review it first.
If I just eat an apple after my meal, my teeth retain a sqeaky clean feeling. Don’t know how replicable this is but I highly recommend trying it.
But eat good apples—Envy, Braeburn, Pink Lady, or at least a Royal Gala. Toss the Red Deliciouses into the bin.