I've noticed that the fluoride tray treatments that I do for 10-20 minutes every day cause my teeth to be very white and bright immediately after the treatments. But then, within 1/2 hour, my teeth look dark and dingy the rest of the day. My teeth were never that dark before I started the fluoride. My rad doc did inform me, however, that my teeth would stain from the treatments, so I am not shocked by it. I just don't feel like I have a nice smile anymore and was wondering.......Is it safe to have teeth whitening done either with trays or lazer whitening after radiation treatments to the head and neck? If so, are there any negative side effects from whitening? Thanks!