I had the HBOT on the recommendation of my oral surgeon.
He had conferred with my radiation oncologist and knew the radiation I had received.
He gave me a choice to get HBOT or not.
I told him to just go ahead and pull the tooth.
He seemed very concerned and I could tell by his words and demeanor this was in his opinion a very serious situation.
So I agreed to the HBOT and was to get 30 treatments pre-extraction and 10 for follow-up.
I did get the treatments and had the extraction and it healed up fine and I am very thankful for that.
You can also get complications from HBOT also.
I had my 30 treatments and the extraction and did 6 of the other 10 and had to quit as I got double vision which lasted 2 weeks.
Vision problems are one of the known possible after-effects of HBOT but your vision should return to its baseline or close to it.
It is not guaranteed to stop osteoradionecrosis (ORN) but I figured if it increased my chances to have a good outcome I would do it.
Because the end result of a bad outcome is going to a major hospital and having bone taken out of another part of your body and removing the bad part of your jawbone and replacing the bone in your jaw I believe quite an operation and recovery.
I have been looking at several websites and studies but the jury is still out on the absolute help of HBOT in these cases.
The best I can figure is it increases your odds of having a good outcome.
I would say anyone having post-treatment extractions or more involved dental issues should have your oral surgeon work closely with your radiation oncologist to be sure you are taking the best path in your particular situation.
Also, your oral surgeon commented you were 3 1/2 years out of treatment but I am not sure if that factor is as relevant as the amount of radiation you had and what area it was focused on, and the amount of permanent damage that may have been caused.

From the Oral Cancer Foundation quote--
Osteoradionecrosis is an extremely serious complication for patients requiring tooth extraction after radiation therapy, and the risk does not appear to diminish with time (for the rest of his/her life the patient should never allow a dentist to extract a tooth after radiation therapy without consulting a radiation oncologist). The ability of the bony tissues to heal is compromised by hypovascularization. Essentially, the radiation destroys some of the very small blood vessels within the bone. These blood vessels carry both nutrients and oxygen to the living bone. A reduction in these vessels correlates to a reduction in the bone’s ability to heal itself.

I am glad you had an easy quick extraction but please watch the area closely and if healing is not in the normal progression range get with your doc immediately.
You can also do follow-up HBOT even though you did not do it pre-extraction.
This is just one more thing that plagues us post-treatment in the H&N group
I know MikeMetz who posts on here has had osteoradionecrosis and had the HBOT and still needed the jaw bone repaired.
So it is not guaranteed and is really on a case-by-case basis and is between the patient and their oral surgeon and radiology which is the patient's best option.
Below are links if you need any more info--
https://oralcancerfoundation.org/complications/osteoradionecrosis/

If my patient has undergone radiation treatment of the jaw, does he/she need hyperbaric oxygen therapy before I extract teeth or perform other minor oral surgery?

https://jcda.ca/article/a31

Although radiation therapy is a common treatment for head and neck cancer, osteoradionecrosis (ORN) represents a major complication during or after treatment.
https://jcda.ca/g24

And here is the link to the search I did as there are many more posts on this subject if you wish to read further.
https://www.google.com/search?client=firefox-b-1-d&q=head+and+neck+patient+when+should+we+get+hbot+before+tooth+extraction

Wishing You The Best-Take Care-God Bless-Russ