Susan, I agree with Christine. I developed ORN in 2010 as a result of RT in 2005. ORN presented with trismus, bone showing and a fistula from the oral cavity through my cheek. I have had HBOT and several bone debridements. Have you had your necrotic bone removed? HBOT is great and does increase vascularization and help healing, but it does not stop ORN. I understand that ORN is rather rare, although it does seem to be under-reported. An additional factor for me in the development of ORN may have been treatment with bisphosphonates (Fosamax) for my osteoporosis for several years prior to my 2005 cancer treatment. Despite use of fluoride since 2005 I have had a number of caries and have required fillings and crowns. No loose teeth at this time and no pain for me. The medical professional who has been most helpful in guiding my dental and ORN treatment has been my oral surgeon who is an MD ~ not all oral surgeons are doctors.