Q. Do you think fasting in itself could cure bruxism?
A. Unlikely, I'm afraid. However the common denominator with bruxism seems to be an overload of stress; this could be addressed by various means such as EFT and even Hatha Yoga relaxation techniques and practices, which will probably help enormously.
I am not that familiar with bruxism as a disorder, but those are my own thoughts on the matter.