The infection could be the reason for the lower immune system and other issues. I have met many people who recovered their health after they fixed their dental issues-I recovered my health after I fixed my jaw issues. None of the people who recovered got root canals.

Know that many serious doctors think root canals are terrible and always harbor infection. We wouldn't leave a dead finger or hand on or for that matter a dead kidney. do some research-docs love them- root canals are easy and they make good money on them. Also it usually take some time until the patient ties it together.

Dental infections can kill people-or give them long term terrible health. This chart may be interesting

http://mydentistaz.com/interactive-meridian-tooth-chart/