First only go to a dds that actually has found infections under root canals before-without pain being present. Many dds have never done this. Xray-pano and cat scan sometimes show a shadow. check youtube vidoes on cavitations.
Mine were found using a eav device. Cavitat also works well.
Dumb luck I sat next to Huggins a week ago and I asked him-he said you need to get a dds to open up and look. You can call his site and ask. I have also found that if I suspect an infection there always has been one. Trust yourself-the human body has more biofeedback systems than any xray or scan