My dentist after scanning my tooth via X-rays said the previous dentist who removed the nerve from my 6-th tooth left a small piece of his instrument in a root canal and filled it with the substance which has formaldehyde in its composition. As a result, my current dentist after 2 unsuccessful efforts to penetrate the root, claimed it's impossible to remove the remnant of the instrument by any means. The thing is I have a small enlarged painless lymph node under that tooth. So now that she says it's impossible to penetrate the root to cure the lymph, are there any other alternative ways of doing this? Is it really impossible or id just the incompetency of my dentist? Thank you.