My son did that. Once we took him off milk because he seemed allergic to it, and a couple of months passed with no milk or by products in his diet, he quit grinding his teeth too. Milk caused all kinds of problems for him, but it was constant coughing and sniffling that lead us to change his diet.
I tried that, we went about 3 weeks without milk but it didn't change anything. He does it when he gets excited or gets mad, it's not like he does it when he sleeps or when he is just sitting there. But thank you for the suggestion : )
