HI Kate,
My husband Steve did 30 dives prior to surgery for ORN exposed infected bone in his maxilla and also to remove a wisdom tooth lodged in his sinus. He suffered along taking antibiotics on and off for 6 months before surgery was decided. The HBOT was time consuming but needed before surgery. We were told the hole left in Steve's upper jaw after surgery would never close and he would wear a huge prosthetic. Well thanks to the HBOT the hole closed nicely in 2 months. He was considered a grade 4 before surgery. I could see the exposed bone and lots of infection. He hated the HBOT treatments but I really believe they helped him heal. He went to a facility for HBOT where it was a multi chamber. There were other people in the sessions along with a great team of specialists. Every day it took 4 hours but 2 hours of that was driving. I went with him everyday to encourage him and make sure he completed the 30. It was tough but well worth it.