Is there a threshold dose to the mandible above which you consider prophylactic HBO prior to dental extractions that are required after RT?  

We do not consider HBO before extraction from parts of the mandible that had received high doses. If ORN happens, we would refer the patients to surgical debridement of the affected area if it does not heal spontaneously. Our experience is that strict prophylactic dental care, as well as IMRT aiming...

Around 60 Gy.