This mandibular molar was previously accessed by an endodontist and then referred. There was a perforation mesially and the canals were located in strange positions. To add to that, the canals were very hard to negotiate and the “feel” was very different to conventional canals. The dentine felt harder than usual. I didn’t want to risk using rotary niti in this case because the feel to rotary too was different when i tried. So, I hand-filed all the canals. Skinny preps in the canal and MTA to seal the Perforation.