Most of us have been using fluoride trays on a daily basis during radiation and pretty much daily after treatment (forever). Many also use fluoride toothpaste.
Good oral hygiene is a must. My dentist has me coming in for a cleaning and check-up every 2-3 months.
Many of us use Biotene products (toothpaste, mouthwash, and moisturizer) � they have a line of products for dry mouth that contain enzymes needed to maintain a healthy oral balanced environment.
Radiation to the jaw puts you at increase risk for Osteoradionecrosis (ORN). ORN is defined as a necrosis or death of the bone of the mandible or maxilla that may occur following radiation therapy for cancer in the oral and perioral region.
Did his dentist take x-rays of his teeth? It is important to have a good oral exam before treatment begins, and have any dental problems corrected before radiation begins. After radiation, dental problems are much more difficult to treat and heal. I had my wisdom teeth pulled before treatment because they felt I could have trouble with them in the future.
If he develops ORN or needs dental work post-RT, they will most likely recommend hyperbaric oxygen therapy (HBO).
My teeth were in good condition before treatment, been doing all I mentioned above, but found out recently that I was developing ORN and just complete a series of 45 HBO treatments.
Also, I recently switched to a different dentist. The dentist I went to for years, who I really liked and he continues to treat the rest of my family, didn't have that many patients with oral cancer. I was starting to have some problems with my teeth, and got a recommendation from my RO for a dentist (actually a prosthodontist) who treats a lot of oral cancer patients. Something to consider.
I hope I was able to answer some of your questons. If not, there is a lot of information on the OCF website addressing these topics.