I used it on my jaw without problems and I have a mouth full of amalgam. I went over my jaw with the magnetic pulser from Sota moving it half the distance of the paddle each time. I did the outside of my face, cheeks, top teeth, lower teeth, up under the chin etc. Probably did 50 zaps on my face/jaw alone and no trouble at all. No heating of amalgam, no sensations.
Hope that helps.