Hi Robin. That is my daughters name by the way.
IMRT is narrow bean radiation. It damages less area as it is more capable of directly hitting the spot where the cancer is.
The simulation and mask will take a while and may cause her some pain. They told me I could take a pain med before I came or a tranquilizer whichever I preferred.
The mask is mesh now and it not as bad to make as the old kind. Mine dried in less than 5 minutes so I worried over nothing.
As for the teeth I wear denture so have no clue. There will be some side effects of course but there are meds for everything to either stop them or make them bareable. I believe side effects vary with each person.
May God go with your sister and your family,
Barbara~