When you're mewing you may've noticed that there's a necessity to swallow your saliva. The reason I want to talk about this, is because I noticed there has been some staining in my teeth and I floss and brush my teeth. So I have concluded that my saliva has not been reaching does places that may be the culprit, after all your saliva is your natural tooth cleanser it fights the germs in your mouth and is capable of breaking down food along side with your teeth.
My solution is to combat this is to spread it around my teeth with my tongue, or to gurgle with it as if it were mouth wash.
Don't do this too much it can interrupt your mewing. So what do you think about this theory?
Mastic gum has the tendancy to increase your saliva's pH values which is good for your teeth. You can do the rest of the research on your own, because you'll learn more that way. You now know what to google for though, goodluck :)