I HATE my fluoride gel...it tastes like s___t, and I can't rinse the taste out of my mouth for half an hour after using it. But I still do use it 5 years out from treatment. Not every day like the docs at MDACC wanted, but at least 3 nights a week for 15 minutes at a time. The truth is that never again will you have the protective benefits of saliva, and all those good enzymes in it. You will also have some decalcification of the teeth, though not visible to the naked eye, that leaves them vulnerable to dental caries as well. Fluoride is the only defense against serious problems, along with a religious involvement with your toothbrush and floss, interdental wooden picks ( J&J) and anything else you can do to keep those pearly whites free from plaque and bacteria. I even get my teeth professionally cleaned every 8 weeks, and with all that I do, she still scrapes off bunches of... mung. For radiated patients the loss of a tooth to periodontal disease from poor hygiene could lead to an open non hgealing socket, or extraction which could lead to osteoradionecrosis, a very bad hombre.