You usually don't need HBOT for root canals, and believe crowns also. It's when a tooth is extracted, gum work, surgery that can cause injury. The majority of ORN is caused after a tooth extraction, not just after radiation, but if its done too soon before radiation also.
It may be best to involve your ENT, Radiation Oncologist to see what their input is, radiation dosage to involved area, and type of dental work to be done.
Good luck
