I have done massive amounts of fasting and have not seen that happen yet. I have one cavity in a back molar that has stopped pitting out but it has not healed over. I am happy that it at least has stopped pitting out,lol.
I have read somewhere that over time with fasting and the living foods diet that people have grown new teeth, and even whole sets of teeth.
Anything is possible with good education and proper mindset.
Just my $1.30's worth,