I can get more info to clear up any misinformation, but this is what my radation doctor told me.

The wax does not prevent the radiation from hitting it's target.
However, a very small residual radiation somehow pings off the metal to your cheek. It touches you cheek just enough to create a sore point. The wax will help prevent that occurance.

Concerning the tongue. Just assuming here, but since the tongue actually touches my teech, I think that the wax moves the tongue away to prevent sores.

I just hope it works.