I did 30 HBOT in 2011 for a tooth extraction after 70Gy, bilaterally for tonsil, lymph node cancer. I need all my teeth extracted now, and in my 4th week of HBOT. I finish on Thursday, and scheduling my surgery with my CCC Oral/Maxillofacial surgeon upon his return from vacation. All my doctors at the CCC agreed I have to do HBOT. Other factors include the radiation dosage, I read anything above 60Gy, some say 45Gy, and depends on areas radiated, and teeth involved. Mandible is usually affected more by ORN than maxamilla. There is probably some debate if HBOT is effective at all, by some, but the risk is so devastating that HBOT is usually sided with. If root canal can be done, that may be preferred, and no need for HBOT.
Good luck.