Root canals are definately a problem for your health. Almost impossible to get the whole root cleaned out, so it gets infected. There is no blood supplied to a dead tooth,so your system cannot fight the infection.
Nobody wants to lose a tooth. I know I went a couple of years before I realized that the AMA couldn't do anything for my problems so I had them removed. My health improved almost immediately. The constipation may just be lack of fiber in your diet, but the nerve problem may be arthritis which can show up any where in your extremities.
You can try and match up health problems with this meridian chart to the tooth/teeth in question.
http://naturaldentistry.us/holistic-dentistry/meridian-tooth-chart-from-encin...