If possible it's best to see a dentist that is very familiar with oral cancer issues. If he's being treated at a CCC they will have such a dentist on staff. If this is not possible do explain in detail his Tx to the dentist.

Radiation can damage the blood supply to our teeth and gums and over time this can lead to infection, etc so it common with the old rad method, RT, they would likely recommend pulling all the teeth in harms way. It was also more common to see poor dental hygiene in OC patients. Now with more refined rad methods, IMRT and Tomo, the damage can be greatly lessened and with the advent of HPV+ SCC less patients present themselves with poor dental hygiene so we now see the recommendation to just pull the teeth that will need it anyway, fill cavities, switch out metal fillings, do a thorough cleaning and add daily fluoride treatments.