Interesting discussion. I've pondered about it many a time myself.
The only thing that was able to rid my white tongue temporarily was oral probiotic capsules from UDO's. However, once I discontinued use for a couple of days it returned.
They are expensive and with all the other costs I'm incurring I couldn't keep them up.
Diflucan does not seem to be having an impact on my tongue.
My hypothesis is that it has to do with food allergies and malabsorption . . .
It's frustrating but if I can get to the place where I am otherwise healthy this tongue thing won't be co much of a bother.
I may soon try zinc lozenges and the oral probiotic lozenges again to see if it helps.