Here's more concerning trismus and fluoride:
Trismus is being unable to open your mouth wide (apparently the radiation affects the fiber in the muscles or tendons of the jaw; I didn't discover I had it until I tried to take a bite of an apple and discovered I couldn't open wide enuf to take a bite!)
Do a search of the site (go to bottom of Forums Page and click on Homepage, then click on Search; the search button at TOP of page only searches the forums.
Here's the link:
http://www.oralcancerfoundation.org/dental/trismus.htm Opening wide often and putting tongue depressors across your mouth and biting on them are both supposed to help, plus there is some sort of rubber wedge system available ($$ prescription) to keep it from happening. It sneaks up on you, esp if you are getting your nourishment from a PEG (feeding tube) because you aren't opening your mouth much.
The fluoride treatments (using a paste called Prevident) are done once a day, every day for as long as we have our teeth (hopefully the rest of our lives!) -- After flossing and brushing my teeth at night, I put the paste on my wet brush and brush the stuf in, then hold it for at least the recommended ten minutes (usually longer as I feel more is better in this case) and then don't eat or drink anything for at least one-half hour after the ten minutes is up. If one uses the trays, put a line of paste in each of the uppper and lower trays and then put them over the teeth for the allotted time.
My dentist writes a prescription for the Prevident and I get it filled at the pharmacy (dentist wants almost $20/tube, pharmacy is lots less expensive thru my drug plan, which doesn't seem to want to mail order the stuff).