Passive ultrasonic irrigation, EndoActivator system and XP-endo Finisher R as additional cleaning techniques to remove residual filling materials from flattened root canals.

Additional cleaning techniques enabled removing a greater amount of root canal filling material from flattened distal root canals of extracted human first lower molars. Considering the total space of the root canal, there were no statistically relevant differences among the groups. In the apical third, XPEFR performed better.