Evaluation of the effectiveness of different irrigation activation methods in removing calcium hydroxide from root canals

Purpose: The aim was to evaluate the effectiveness of different irrigation activation methods in removing calcium hydroxide (Ca(OH)2) from two different root canal isthmuses (apical and middle levels) created using three-dimensional (3D) modelling.
Methods: In this in vitro study, 150 acrylic blocks were divided into 10 groups (n=15). Models fabricated and filled with pure injectable Ca(OH)2 paste (UltraCal XS, Ultradent, South Jordan, UT). Five irrigation activation groups were established (conventional needle irrigation (CNI), EDDY activation, passive ultrasonic activation, XP Endo Finisher activation and Er,Cr: YSGG laser activation). The amount of residual Ca(OH)2 in the root canal isthmus was evaluated with a stereomicroscope at ×10 magnification. All procedures were performed by a single operator. The area containing Ca(OH)2 was subtracted from the total area measurement and the cleaning percentage and area calculation were made using the Image J program. The obtained data were recorded in the Microsoft Excel program, and IBM SPSS v29 package program was used for analysis and visualization of the data.
Results: Er,Cr: YSGG laser showed significantly lower amount of Ca(OH)2 remnants compared to other methods (p<0.001). In the apical isthmus region, EDDY was the least effective method, while in the middle isthmus region, the CNI method was the least effective.
Conclusion: Er,Cr: YSGG laser-activated irrigation technique demonstrated superior efficacy in the removal of Ca(OH)2 from root canal isthmus regions than other activation methods. 3D modelling enabled the comparison of irrigation activation methods in a standardized manner.

Keywords: Calcium hydroxide removal, EDDY, Er, Cr: YSGG, irrigation activation, isthmus, passive ultra-sonic activation, XP finisher.