In the After Treatment Issues forum there is a thread entitled "long term effect on teeth from radiation" (started March 2006) that has information on ORN. It may not deal directly with a situation like yours, but it will allow you to get in contact with people who are knowledgeable about this. I'd particularly recommend wilckdds, who is a dentist and an oral cancer survivor. You can get in touch with him directly by clicking on the e-mail or private message icons next to the date of his post.

You can also do a general search of the forums for "osteoradionecrosis." (The search link is at the top of each page, underneath and just to the left of the photographs.)

All the best --
Leslie