K.A.
Hi,
I also have two sons : ) My youngest will be 9 months tomorrow. He has six teeth now (4 top, 2 bottom) and grinds them all the time. I don't think it really hurts anything except maybe our ears. I think it just feels good while they are teething and it's new to them so they do it. He should just stop on his own as the novelty wears off. Good luck!