Hi Ray,
I began using my trays before I started radiation and was told to keep them in my mouth for 10-15 minutes, but not wear them overnight. I was supposed to use them throughout treatment, but towards the end my entire mouth and gums were so sore and tender that I had to stop using them.
Your mouth will be extremely sore from the radiation, and you will probably be given prescription rinses to use and also told to rinse frequently with salt water/baking soda mixture. My doctors recommended Biotene products (toothpaste, mouthwash, etc) as they are non-irritating. I finished radiation over 2 years ago and my mouth is still very sensitive and I'm unable to use many toothpaste brands. Flossing is important, but I wasn�t able to reach my back teeth so I switched to Reach flosser or floss picks.
My teeth were in good shape to begin with and my dentist said I didn't need to use the fluoride trays after treatment was over. Instead of going to the dentist every 6 months, he recommended every 3 months. However, I recently switched dentists and had my first dental x-ray since radiation, and they determine that my jaw bone has deteriorated and I�m at high risk for developing osteoradionecrosis (ORN). After a consultation with my oral surgeon they recommended I see the dentist every 2 months for cleaning and check-up, and they also recommended hyperbaric oxygen therapy (my last dive is tomorrow). They also recommended I start using the fluoride trays again, every night forever! We are at a higher risk of loosing teeth and developing other dental problems, so I feel these added preventative steps are worth it.
By the way, I�m also from the Lehigh Valley and see both Dr. Koch and Dr. Risch. My reaction to radiation has been extreme and I continue to have healing issues. Dr. Risch said I�ve had the worst reaction to radiation of the mouth that he has seen. Hopefully your experience will be much better than mine.
I hope I answered at least some of your questions. Good luck!