I have osa (use cpap) & wake up with horrible pain in my top front teeth from tongue pushing hard against them all night. can this cause root damage?

Needs to be checked: Pain in the teeth may have many causes. The tongue itself can not damage the teeth but this may be a sign of teeth grinding (bruxism) which is quite common in apneic patients. There also may be an issue with how your CPAP mask is fitting. You should talk to a dentist, preferably one with experience treating sleep apnea patients.

Common problem: Any continuous pressure, such as the mask, can cause your teeth to move and create endodontic problem. Common problems with CPAP include a leaky mask, teeth movement, trouble falling asleep, and a dry mouth or nose. See your CPAP tech for mask adjustment.