Reciproc-Blue was more efficient than XP-endo-R in retreatment teeth obturated-with single-cone-technique however XP-endo-R was more efficient than Reciproc-Blue in retreatment of teeth obturated-with warm-vertical compaction-technique. XP-endo-R may be used in retreatment small-size canals only, it may be more-effective rather than in medium-canals like this study although XP-endo-shaper can expand within canal, but maximum expansion reaches to-#30/0.04. XP-endo-shaper has a snake-shape which is the most benefit in quick glide-path by rolling-GP around its long-axis rather than accomplish retreatment. Further studies were employed to compare the performance of XP-endo-shaper at different speeds.
