Effects of size and operating mode of sonically oscillating files on irrigant extrusion

Abstract

Objective: The purpose of this study was to evaluate the effects of size and oscillation frequency of sonic tips on irrigant extrusion during activation. Materials and Methods: Twenty artificial maxillary molar tooth models were used in this study. The palatinal canal of each model was prepared up to final apical size of #40. Each specimen was mounted on a glass vial filled with saline solution to simulate a periapical lesion. The initial weights were measured using an analytical balance with 10-5 g accuracy. Then, a series of irrigations were conducted according to the size (15/.02, 25/.04, 35/.04) and operating mode/speed (low, medium, high) of the sonic tips. In control group, the irrigant was delivered by placing the needle tip at the access cavosurface, without the insertion and activation of the sonic tip. The mean weights of apically extruded irrigant were calculated by subtracting the mean initial weights from the final weights of test apparatus. Data were statistically analyzed by the Kruskal-Wallis and Siegel Castellan tests. Results: The use of 15/.02 tips resulted in higher irrigant extrusion than the control only at high speed while the 35/.04 tips only at low speed (p < 0.05). The 25/.04 tips presented higher extrusion than the control with all operating modes (p < 0.05). At high speed mode, both the 15/.02 and 25/.04 tips were associated with higher irrigant extrusion than the 35/.04 tips (p < 0.05). Conclusion: Both the size and oscillation frequency of the sonic tips had significant effects on irrigant extrusion during sonically activated irrigation.