A fundamental step in non-surgical retreatment is the removal of the existing root filling material to permit radicular access. Different root filling materials require different techniques of removal. The endodontic literature is littered with studies exploring the relative merits of one technique of removal over another. In this review, the focus is on the experimental models and techniques employed to investigate the removal of root filling materials during non-surgical retreatment. The correlation and clinical relevance to everyday endodontic practice is also discussed. Keywords: non-surgical retreatment, root filling materials