Discussions

After having a few root canal procedures done did you feel unwell maybe not right then but, maybe six months to a year later ? I was doing some research noticed some of the materials used are toxic . This person I know has developed a horrible cough has a hard time breathing and has passed out . few times . Gone to doctors they can not pin point what they might have . It was just a thought I had about the root canal and then they seemed to start feeling unwell . What I read that maybe seepage happening going through body and created a problem . Maybe similiar to breast implants they can have seepage make a person really sick . thoughts

I haven't had one but loved ones have. My understanding is that that the material used are similar to what is used in a normal filling. They often need to be capped or crowned.  
 
It seems unlikely that feeling ill 6-12 months after a procedure is due to the procedure itself. If anything, if it has anything to do with the root canal, it might be a latent, underlying infection under the cap/crown bit. Those can fester a long time and get into the bloodstream etc. Is there pain or anything that suggests the root canal has a problem?  
 
Odds are it's coincidental that their issues are because of the root canal. They are generally safe and people tolerate it well. The materials used, while not completely inert, are generally recognised as safe and pose no safety hazard to the vast majority of patients.  
 
I hope your person feels better soon and the doctors can figure out what the issue is.