A flipper (a simple removable PARTIAL denture made from plastic) is only a temporary device, custom made for a particular individual, by a dentist and lab, that will replace one or two teeth. It is no good for eating, only looks. A person who has had all their teeth extracted needs a complete denture, and this is a whole 'nuther animal. Teeth that are marginal for long term survival, have extensive decay, have periodontal problems, etc. must be extracted before radiation, as any post radiation extraction will cause severe consequences. If the teeth were extracted, the doctors must have felt that they were in bad shape or the surrounding tissue and bone had perio problems that might have caused them to be lost after radiation. Teeth are not arbitrarily extracted prophylacticly