Godzilla has been terrorizing the populace since 1954. And in those 58 years on the silver screen, no one seems to have figured out how to disable his main tool of destruction; namely, his atomic fire breath.
Fear not, citizens!
Modern dental science coupled with current reactor control rod cladding
and neutron absorbing materials may have found the cure!
Here's how it could work:
Godzilla is no spring chicken. Years of eating fish (and advancing armies, one would have to imagine), along with his steadfast refusal to floss, has taken its toll on his teeth and gums. Our best guess here at GROGco Movie Monster Neutron Absorbing Denture Testing Laboratory, is that he is long overdue for dentures.
When he goes in for the inevitable, simply replace the dentures he expects with a set of GROGco Movie Monster Neutron Absorbing Dentures. The teeth are made of a sturdy cladding, chock full of a boron based neutron absorbing material commonly found in modern nuclear reactors.
After that, the next advancing army need only prepare itself against movie monster bad breath.