Kind of rare to see these wide open canals on a 60 year old. The patient initially presented with buccal probings to the apex on this second molar. I used some pre-bent 10 and 15 files on the distal, mesial lingual, and mesiobuccal canals. I used a 7.04 rotary file on the mid-mesial canal. Instrumenting large canals takes a little more time. Continuous taper shaping of these canals would have likely perforated it coronally. So for these large canals, this is root-form appropriate instrumentation of the internal aspect of the root. Looks like there were 3 POE’s on the MB root. The lateral canal evident on the postop may have contributed to the furcal blowout.
-Trudeau