"... root canals are often the cause of health issues."
Dr. J. Tennant has a fascinating theory on that subject! Dr T is the doctor who did most of the testing of Lasik eye surgery. He almost died due to unforseen side effects from exposure to viruses in the eyes.
Dr T measures the voltage in the acupuncture meridians--our electrical circuits-- and compares that to the voltage in the mouth. He has so often noticed that bad dental situations take down the voltage on the circuit going through the jaw near the bad teeth.
The body needs additional voltage in times of healing. For example this has been tested in salamanders who can regrow limbs.