INTRODUCTION: A greater irrigant volume improves the effectiveness of root canal irrigation. The purpose of this study was to compare 2 negative pressure systems regarding the volume of irrigant collected from the apical area in moderately curved canals at 3 different flow rates of delivery in vitro. METHODS: The mesiobuccal canals of 30 molars with a curvature between 20° and 40° were prepared to size #40.04 taper. A closed system was created. The canals were irrigated at 3, 6, and 12 mL/min for 30 seconds using EndoVac (SybronEndo, Orange, CA) and the INP needle (Mixnus Fine Engineering Co Ltd, Nagano, Japan) (both independent variables). A recovery trap was used to collect the irrigant aspirated by the negative pressure needles. Irrigant volume (dependent variable) was measured in milliliters. Data were analyzed using mixed analysis of variance. RESULTS: There was a statistically significant interaction between the negative pressure system and the irrigant volume collected (P < .0005). The mean irrigant volume collected by the different negative pressure systems was greater for INP at 3 (P < .001), 6 (P < .001), and 12 mL/min (P < .001) flow rate. Both negative pressure needles showed statistically significant differences (P < .001) between mean irrigant volume collected at different flow rates. CONCLUSIONS: A greater volume was collected by increasing the flow rate of irrigant delivery for both EndoVac and INP. The INP needle could collect a greater volume of irrigant from the apical third compared with EndoVac at all 3 different flow rates.
INTRODUCTION: A greater irrigant volume improves the effectiveness of root canal irrigation. The purpose of this study was to compare 2 negative pressure systems regarding the volume of irrigant collected from the apical area in moderately curved canals at 3 different flow rates of delivery in vitro. METHODS: The mesiobuccal canals of 30 molars with a curvature between 20° and 40° were prepared to size #40.04 taper. A closed system was created. The canals were irrigated at 3, 6, and 12 mL/min for 30 seconds using EndoVac (SybronEndo, Orange, CA) and the INP needle (Mixnus Fine Engineering Co Ltd, Nagano, Japan) (both independent variables). A recovery trap was used to collect the irrigant aspirated by the negative pressure needles. Irrigant volume (dependent variable) was measured in milliliters. Data were analyzed using mixed analysis of variance. RESULTS: There was a statistically significant interaction between the negative pressure system and the irrigant volume collected (P < .0005). The mean irrigant volume collected by the different negative pressure systems was greater for INP at 3 (P < .001), 6 (P < .001), and 12 mL/min (P < .001) flow rate. Both negative pressure needles showed statistically significant differences (P < .001) between mean irrigant volume collected at different flow rates. CONCLUSIONS: A greater volume was collected by increasing the flow rate of irrigant delivery for both EndoVac and INP. The INP needle could collect a greater volume of irrigant from the apical third compared with EndoVac at all 3 different flow rates.