I saw your question posed on several sites and it looks like you have not received any satisfactory answers yet. I'm very curious about whether or not what happened to you was caused by this device. I wanted to get one but after reading your concern I'm not so sure I want to now as I already have several crowns of which I know one has a metal post. If anyone were to get zapped from anything, it would be me. That's why I'm afraid to use this device now. I'm the one that touches the metal frame on a door when entering a store and I'll get zapped. Get out of the car and accidentally touch the metal frame on the outside of the car and get zapped.

My only question to you is - did you use the device with a wet hand as instructed? Wonder if that makes a difference.