There's plenty of evidence that root canaled teeth are major harbors for bacterial growth and directly tied to various chronic diseases; but again so is mercury; personally I would not do any work on those teeth with root canals because they are dead and simply blocking energy flow through the specific meredians; I would save the money I would be spending for Amalgam removal and crown placement for those 2 teeth (~$3400?) and have them extracted; I've had 2 root canaled teeth removed so far and physically saw the infection (cyst) and smell the putrid odor coming out of it (X-rays showed no signs whatsoever of this infection).
I'll be having my last root canal tooth in march and hopefully it will heal before I leave for Japan in May
Mike