During a root canal process of the lower left first molar - having sever pain in the upper left teeth

[SSPatient]

Hey Doctors,

I'm during a root canal process of the lower left first molar (6th from the middle).

Went to the first dentist on 30/5/21 because I had a hole in an old filling she found 3 canals and did the root canal on one session - after this process started to have severe pain on this tooth and on the upper teeth as well.. she told me to wait but it didn't help - so on the 16/06/21 I went to another doctor which found a 4th canal and he treated only this one (without retreating the others) - it really helped to decrease the pain but I still had major pain and swelling on the upper teeth.

I feel like there is an infection in these canals of the lower left molar which causes inflammation on the upper left side it lasts for more than a month and 2nd dentist doesn't see any issue.

Attaching here bite wings X-rays I did today 11/07/21 and panoramic X-rays before I started with the procedure on the lower left first molar (6th from the center).

https://imgur.com/a/UV0OscG

Please advice - I'm really at a loss .

Thank you in advance,

Patient with severe pain.

 

[Dr M]

Good day

Have you been referred to an endodontist? This is a specialist that deals with root canals. He will be able to do a CBCT scan of the tooth, which gives a 3D image of the tooth, which might give some more light on the situation.
There are a lot of reasons why a root canal can still give problems. Were the roots short-filled? Were the root canal systems properly disinfected prior to completing the root canal? Is there perhaps a crack in the tooth?
The specialist would be the best possible guy to see in this regard.