It's not conclusive by any means but Mythbusters tested this and came to the conclusion that tooth filings don't act as an antennae:

http://mythresults.com/episode4

Sometimes the Mythbusters do interesting things, but their ad hoc methods, largely uninformed by theory, are often so haphazard that they prove basically nothing.

Well, if they can manage to reproduce a phenomenon, however they stumble on it, it's pretty conclusively confirmed.

There's definitely doubt about their conclusion when they can't reproduce something and then declare it busted -- absence of evidence is not evidence of absence.

I can think of one "confirmed" myth involving bacteria that was likely invalidated by improper sample handling. The lab scientist who ran the test appeared to be straining to say that without overstepping her remit on the show.

But do some, imperfectly fitting, filings act as a diode?