It's called bruxism and no one really knows why it happens. It might be because your DD has an earache or her top & bottom jaw don't align properly or she might be teething. In adults, bruxism often happens because of stress, and kids can grind for the same reason. There may be no reason at all & it's just something she does. Most kids do outgrow their bruxism, but if you notice any damage to her teeth or if she is complaining of headaches or jaw pain, you should take her to the dentist to be checked out (you may want to do this anyway). If she's clenching/grinding really bad, she may need to be fitted for a bruxism guard, although I don't know if you could get a 2 y/o to wear one.
at 10:33 PM on Dec. 1, 2010