Could teeth be stained by the white wine?
Unfortunately (because I am HUGE Pinot Grigio fanatic), yes.
On October of this year an article was published in fitsugar.com that I actually read back then, where it states that the acidity in white wine can be higher than red and hence the combination of acid in your own saliva (and we know how much we love enjoying the wine) plus that of the contents of the wine dissolve the enamel. The lack of tooth defenses may lead to staining.
This does not mean that red cannot stain. It does too. And, surprise! Riesling is the most acidic of all white wines and the one which could be worst for your teeth.
However, there is hope! Pair your wine with cheese to counteract the levels of acid, and the calcium found in cheese might also help mitigate the impact of the drink in your mouth.
Hope this helps!