I too believe that root canals can be the principal culprits in not just candida sufferers but other chronic diseases; my health began degrading after having dental work done (my 3rd root canal). These procedures allow infections to proliferate in the miles of hollow space left in the dead tooth and consequently affecting the whole system, either by spreading infection or by their dangerous toxic waste.
These focal infections are constantly overworking the immune system 24/7 which allows other infections to occur (bacterial, fungal, parasitical) since the immune system is too busy attending other matters.
I would be curious in knowing how many candida sufferers have root canals; those with candida and without root canals or other chronic infections can get rid of the overgrowth with the anti candida diet and never have it reappear, but there are many people who get better with the diet but fall ill again, indicating that their immune system is too weak (or busy fighting other infections) to fight the resurging fungus.
Is the paper your friend wrote available for others to view it?