Ive never heard of wearing flouride trays during radiation treatments. The mouth guard is something different. I definitely would ask your radiation oncologist about this well in advance of rads starting. I didnt use the mouth guard but some members here have. From what I understand its something patients bite on during their radiation treatments. As far as the exact reason for using it, Im not sure. Maybe its to stabilize the patients mouth to keep it completely still, it could be necessary for some due to how their mouth is shaped, or maybe its needed for patients with certain fillings? Hopefully someone who used one or cared for someone who had it will reply.

As far as the flouride trays go, that is a necessity. Anyone who does rads should have and use them on a daily basis.