Effect of Passive Ultrasonic Irrigation on Apical Extrusion of Irrigating Solution

OBJECTIVES: To determine the influence of passive ultrasonic irrigation (PUI) on apical extrusion of irrigating solution. METHODS: Twenty freshly extracted maxillary and mandibular incisors with single straight root canals were instrumented with ProTaper rotary files. During final irrigation, the root canals were filled with 2.5% sodium hypochlorite (NaOCl) solution and PUI was performed with a piezoelectronic unit. A stainless steel instrument (size 15) was inserted into the root canal and the irrigant was ultrasonically activated for one minute. This sequence was repeated three times, resulting in a total PUI time of three minutes. The volume of extruded irrigant was measured by Pipetman pipettes. The data were statistically analyzed with the Mann-Whitney U test. RESULTS: The mean volume of apical extruded irrigant was 2.15 μL for the PUI group and 14 μL for the control group. The experimental group extruded significantly smaller amounts of irrigant than the control group (P<.05). CONCLUSIONS: The PUI procedure as a final irrigation was associated with less apical extrusion of the irrigating solution.