Root canal instrumentation is one of the major tools for ensuring the long-term success of root canal therapy. The aim is to mechanically disrupt as much biofilm as possible so that with the addition of irrigants and/or intra-canal medicaments a very low microbial count can consistently be achieved before the filling of the root canal. Another aim or challenge of root canal instrumentation is to achieve the microbial reduction goals mentioned above without unnecessarily weakening the root by over-instrumentation, for example through the reduction of the dentinal wall thickness. Preservation of native structure, especially in the cervical region of the tooth has been demonstrated to correspond to better long-term survivability from a loading and restorative standpoint. It is well established that as the remaining dentine thickness decreases so does the root’s resistance to fracture.