Orthoradionecrosis of the jaw I think is the name for the "dead" bone. It is a serious problem because it interferes with the healing of any dental procedure. My oral surgeon has said to wait until I have a real problem and then he would probably treat with root canals. Watch out for any other medications that you might get. Especially medications for osteoporosis, most of which are bisphosphinates wich cause osteonecrosis of the jaw so it will make the problem worse or vastly increase the possibility of haveing it. BTW, to my knowledge necrosis of the jaw is not diagnosable from x-rays.Clark