didier - Same thing happened to me. Here was the rationale in my situation: Post radiation mouths cannot tolerate injury - even minor injuries like those caused by dentures. ORN is the name of the condition. It is the loss of blood supply to the jaw caused by radiation. The tiniest of injuries can become a very dangerous condition causing extensive damage. My oral surgeon wanted me to go without dentures for two years after radiation ended. I'm glad I waited. I can now tolerate them and my risk of ORN is slightly less. Too bad the docs didn't give you the rationale. Hope this helps. TJ