Thanks for your response.
Sorr yit took me so long to reply. Your explanation helped a lot. The only part I wonder about is that, around the root is dentin, which stays and is alive. but I think that probably doesn't help much if bacteria is left inside.
I guess the right thing to do is extraction, but I need so many done that the cost of implants is enormous. I realy don't want dentures. I'm stymied.