At timestamp 50 seconds, Dr. Breiner tells the story of a patient that was a lady with Coccyx Pain and Back Pain.  Dr. Breiner did EAV Screening her (Electro-Acupuncture Voltage Screening), and he found that a root canal tooth was causing her tailbone pain.  Dr. Breiner treated her, and her Coccyx Pain and Back Pain went away.

Dr. Mark Breiner, DDS in Connecticut (he also serves NY), https://wholebodymed.com/dental-cavitations-are-they-real/ and https://wholebodymed.com/dentistry/initial-dental-visit