I traced the beginnings of my CFS to be temporally related to my first root canal. When I finally had this root canal tooth extracted, the roots were blackened/necrotic. A week later, I felt cured—I felt completely normal again; that my CFS had completely resolved. When I returned 3 months later to start the implant process, the bone this rotted tooth had been sitting in had collapsed quite a bit. Shortly afterward, I had radiation therapy for a very tiny breast cancer, and 3 weeks later was completely debilitated. I have not recovered since. If the maxillary bone that housed the rotted root canal tooth is still infected, how would I know? The rotted roots never showed up on any digital panoramic x-ray or CT scan.