Why my daughter won’t be wearing masks to school anymore :(

So I guess we’re homeschooling the rest of the year/until the pandemic is over.. I’ve been trying to figure out why my daughters teeth have been getting increasingly brown the past few months despite brushing twice a day.

Then I thought okay this has been happening since school started basically..what’s changed? The only thing that’s changed is she wears a mask daily for 6 hours only taking it off to eat. So she eats and puts it right back on and I think the lack of fresh air is what’s caused it..

First 2 pictures are April & August 2020

This picture was today April 2021

I feel so bad for her :( luckily they’re baby teeth so hopefully the adult ones aren’t affected🤞