A series of lectures intended to expose the student to the core concepts and current information necessary for a thorough knowledge of non-surgical root canal retreatment. This course will describe the different outcome measures in endodontics and their assessment; procedures and materials used in the root canal treatment and restoration of teeth; Materials and procedures for coronal disassembly, removal of materials and objects from root canals, identifying previously untreated anatomy, re-negotiation, management of procedural accidents; risks and limitations associated with non-surgical and surgical re-treatment procedures; Factors which may be associated with the success and failure of non-surgical retreatment procedures; features of an appropriate recall strategy; and the need for further intervention in the case of failure or uncertainty.