hi there, I did a 29 day Water Fast and one of the reasons I did it was to resolve a tooth issue. It worked. Also, I think my eyesight improved a bit.
i really believe it's important not to stress the body while fasting, and to rest.
prayer and meditation can be good too, if you're up to it, or my new favorite:
chanting the Hanuman puju sung by Krishna Das. I think i'm going to do a lot of singing on my next fast. :-)