It’s a notion first put forth—and explored—by television…but that doesn’t mean it isn’t true.

It’s been use as a plot device on numerous sitcoms. In fact, Uncle John got the idea for this piece when he was watching an episode of The Partridge Family the other day—Laurie had just gotten fitted for braces, and she kept hearing mysterious music. Turns out the metal in her mouth was picking up signals and broadcasting to an audience of one. On other sitcoms, it’s headgear that brings in the swingin’ sounds, or metal fillings in cavities. But is there any truth to it?

When did the idea first come about?

The idea probably hit the public consciousness in the early ‘70s, around the time that Partridge Family episode aired. TV legend Lucille Ball was a guest on The Dick Cavett Show and told a strange story in which she claimed to have helped capture a Japanese spy back during World War II. In 1942, Ball was filming the movie musical Du Barry Was a Lady at MGM Studios in California…where many feared an attack by Japan could come along any day. One night, she drove home, she heard music…but the radio wasn’t on. The music got gradually louder, and Ball realized that it was coming out of her mouth. She didn’t tell her husband, Desi Arnaz, because she thought it made her sound crazy. But she did tell actor Buster Keaton on set the next day—as a joke (he was a comedian, after all) he told her she must be picking up radio signals.

Morse Code

Ball kind of forgot about until about a month later…when her mouth picked up rapid Morse Code dashes and dots. She told MGM’s security department about it, who in turn called the FBI, who found a secret Japanese-run radio station operated by a spy, right there in Los Angeles. So says Lucy.

The MythBusters connection

Another TV entity enters into the story, too. The team from MythBusters looked into the science behind the story. They discovered that it is feasible to pick up radio signals through a filling, but only if the conditions are right. Gold and amalgam fillings placed inside an authentic human skull didn’t work, but they determined that Morse code could be captured due to a cell reaction between silver fillings and saliva.