Comparison of final irrigation techniques in removal of calcium hydroxide

The aim of this study was to compare new irrigation systems with a conventional irrigation technique for the removal of inter-appointment calcium hydroxide [Ca(OH)(2)]. Forty-seven extracted human single-rooted teeth were instrumented, and Ca(OH)(2) paste was placed into root canals by using a lentulo spiral at the apical third. Teeth were randomly divided into three groups according to different irrigation protocols using a 30-gauge slot-tipped needle, EndoVac system and ProUltra (R) PiezoFlow ultrasonic irrigation system. Scanning electron microscopic images of the selected root canal surfaces (cervical, middle and apical third) were evaluated using a 5-grade scale. The influence of the irrigation system was evaluated using a two-way analysis of variance test and Tukey's test. The EndoVac and PiezoFlow groups demonstrated the lowest scale values (cleanest canals); however, there was no statistical difference between these two groups. The conventional irrigation group exhibited significantly higher scores (P<0.05). The conventional needle irrigation was not sufficient to remove Ca(OH)(2) from the root canal system. Irrigation with EndoVac and PiezoFlow ultrasonic irrigation systems improved the removal of the intracanal medicament resulting in cleaner root canal walls.