I don't know about that since this is only my second fast. I can't remember when it started but me teeth hurt when I brush them. Particularly the teeth that have gold foils or caps. [I got the work done at a dental school, knew silver was bad, and gold was less expensive then the natural looking choice (can't remember what they are called)]. It's not only on the gold, its also along the area where the teeth and gum meet. I've been wondering if my body is trying to heal the gums.