Anyone have any experience with needing to cover or shield metal dental work from rads?

I rec'd a call yesterday from a surviving patient of RO#1. He let me know some about his experience (stellar - probably the "best patient" the dr. had).

He mentioned having metal in his mouth (fillings, crowns), and the need to cover the metal for tx(in his case, by buying and wearing a mouth guard from Dick's Sporting Goods and using wax during treatments). He said this was much cheaper than having a guard made by a dentist.

I had read here that teeth need to be in good condition prior to tx, but hadn't seen any notes on metal. I just had build-up work done on two teeth in preparation for upcoming crowns (metal overlaid with porcelain) and a loose filling replacement.

I had asked my dentist about flouride trays (saw lots of comments on the need), and he let his assistant know to add bleaching trays to my estimate for a later appointment, closer to tx time. These are about $200 for the set. He also said he'd order flouride for me when the time came. The dentist did not mention a need to cover my metal during treatment. I also have a metal retainer cemented in - will it need to be covered or removed?