I started using my trays 1 month pre rad and continued for 5 years post Tx and I never had or have any gum or teeth problems and I'm 7 years post Tx now. Granted I had really good oral hygiene pre cancer and no one can predict any outcomes with this cancer or it's Tx and I'm not a dentist and perhaps yours is correct but at least I think they helped me.

David

Age 58 at Dx, HPV16+ SCC, Stage IV BOT+2 nodes, non smoker, casual drinker, exercise nut, Cisplatin x 3 & concurrent IMRT x 35,(70 Gy), no surgery, no Peg, Tx at Moffitt over Aug 06. Jun 07, back to riding my bike 100 miles a wk. Now doing 12 Spin classes and 60 outdoor miles per wk. Nov 13 completed Hilly Century ride for Cancer, 104 miles, 1st Place in my age group. Apr 2014 & 15, Spun for 9 straight hrs to raise $$ for YMCA's Livestrong Program. Certified Spin Instructor Jun 2014.