Thank you so much for your reply, as we really didn't know where to start looking. He does see a regular dentist and gets cleanings three times a year now, but the dentist he uses hasn't really dealt with this before. Again, thank you!!
Yes, your dental insurance probably won't cover much of the treatment that is necessary. Unfortunately, now that he's lost his salivary glands, his mouth is extremely dry and more prone to gum disease and cavities. Has he been seeing a dentist regularly? Also, you may want to contact your local dental society to find a dentist who is comfortable treating your husband as he has a difficult case to manage. Since radiation was used, its possible that the jaw bone is affected as well, resulting in poor healing. If they remove any teeth, theres a risk of infection. They'll probably try to keep his teeth and put him on a strict cleaning schedule.
You may want to also find out if your health insurance will cover it. Again, a dentist who is comfortable and has additional training or experience in this matter would be best.