Why does the taste of pennies remind you of losing a tooth?

That's an interesting question...why does it? And who conducts the test to see if this is true? Do they randomly walk around asking people to lick pennies, then while their face is crumpled up in disgust, do they rip out a tooth? Or is it the other way around? Do they stalk dentist offices waiting for the scream of pain that follows a good-tooth-yanking then run in and push a penny in your mouth? Asking you...does it taste the same?! Does it!?
Or is it like those people who hang out in the mall "Would you like to take a survey?" Then they ask you random questions like... do you like peas? Have you ever licked a penny? What did it remind you of?
I wonder if all the people who answer the survey prefer to remain anonymous. I mean who wants to tell anybody that they participated in a penny-tasting anything. Really...can you imagine how that conversation would go? "So Jennifer, what did you do last night?" "What Bob? What do you know? Nothing! I did nothing last night...Certainly nothing that involved licking a penny! What's with the interrogation!" (Jennifer crying and pacing the kitchen). Talk about awkward!
I prefer to remain unaware as to why the taste of pennies remind certain folk *wink wink* of losing a tooth. Ignorance is bliss as they say.