the root canal you had pulled, was it by a regular dentist or a biologic one? you may need to have the cavitation cleaned.
as far as chelation, all i can tell you to do is chelate fo about 4 months. use the supplements on my website, take hot baths, go to hot springs (they have sulphur), take mineral baths (epsom salt, for example, and it has sulphur), eat onions, garlic, eggs (foods that contain sulphur).