A colleague asked me on my facebook page what has been my root canal treatment approach to overcome that challenging anatomy. https://www.facebook.com/endomontreal/
A) Never push a straight stainless steel file into the canal in order to reach the foramen with it. You must first bind your first instrument tip and scout in order to be able to feel and follow the canal shape or its direction change.
B) In a case such as this one, you will most likely meet more than a point of resistance before reaching the foramen and you will have to carve your way in deeper. Pushing your way in at the point of resistance with your file will definitively create a ledge or else with their disastrous consequences. In order to progress deeper, you have to enlarge the coronal portion with your ss file using the enveloppe of motion technique. Continues this way until the desired length is achieved.
C) Then, once the foramen has been reached, you can enlarge the canal in order to create a glide path up to size 15. Once the glide path has been completed you could use the NiTi shaping file of your choice. Needed state of mind NO pushing but strong resolution.
Endodontic procedure instrumentation has been performed with Mani stainless endodontic K files and ProTaper Universal (Dentsply). Chelator: RC Prep. PUI Irrigation: NaOCl 5%.