Comparison of the effect of different irrigation activation systems on the amount of apical extrusion of irrigation solution in teeth with severely curved canals.

Objective: This study aims to quantitatively compare the effects of standard needle irrigation (SNI), passive ultrasonic irrigation (PUI), EDDY, photon-initiated photoacoustic streaming (PIPS), and shock wave-enhanced emission photoacoustic streaming (SWEEPS) on the apical extrusion of irrigation solutions in teeth with severe canal curvature.

Materials and methods: Seventy-five teeth with a single root and canal, and curvature angles ranging from 20° to 40°, were selected for this study. Root canal curvatures were measured from buccolingual and mesiodistal radiographs using ImageJ software (version 1.48v; National Institutes of Health, Bethesda, MD, USA). The samples were randomly assigned to five groups (n = 15) based on the irrigation activation methods: SNI, PUI, EDDY, PIPS, and SWEEPS. An irrigation activation procedure was performed for 90 s using a total of 6 ml of 2.5% sodium hypochlorite (NaOCl) (Wizard, Istanbul, Turkey) in all samples. The Myers-Montgomery experimental model was used to simulate periapical tissues and limit the amount of extruded solution. The extruded irrigation solution was collected from the drainage cannula using an insulin syringe.

Results: The data on the amount of apical extrusion of irrigation solution were analyzed statistically using the Kruskal-Wallis and Mann-Whitney U tests, with a significance level set at P < 0.05. While the highest mean solution extrusion was observed in the SNI and PUI groups, the PIPS group showed less extrusion compared to the other groups. However, no statistically significant difference in the amount of apical extrusion of irrigation solution was found among all the irrigation activation methods tested.

Conclusions: Within the limitations of this study, all irrigation activation methods tested on teeth with severe curvature resulted in a certain amount of solution extrusion. However, no significant difference was identified among the irrigation activation methods tested.

Clinical relevance: When these irrigation activation methods are tested on teeth with varied canal anatomies, the amount of apical extrusion of the irrigation solution may vary.