The study compared the amount of apically extruded debris during mechanical preparation of oval root canals using either a full-sequence self-adjusting file (SAF) system or a rotary file system supplemented by an XP-endo finisher file. Sixty teeth were instrumented using the two techniques and debris was collected and weighed. The rotary file system with XP-endo finisher extruded significantly more debris than the full SAF sequence. Both techniques resulted in apical extrusion but the SAF system extruded less debris, suggesting it may help reduce postoperative inflammation.