Efficiency of calcium hydroxide removal techniques from simulated internal resorptions - in vitro study

Introduction/Objective. Calcium hydroxide (CH) is the medicament of choice in endodontic treatment of internal root resorptions. The aim of the study was to compare the effectiveness of three different techniques for CH removal from simulated internal root resorptions. Methods. Twenty-nine extracted single-root teeth were prepared using NiTi rotary files of BioRaCe system (40/.04) following irrigation. A round diamond drill was used in the making of a symmetrical standardized internal resorptions 6 mm from the apex. Three techniques for CH removal from internal resorptions were tested: modified conventional syringe irrigation (CSI), passive ultrasonic irrigation (PUI), XP-endo Finisher (XP). Resorptive cavities and apical thirds were observed under a stereomicroscope (×45) and scored (from 1 to 5), while representative samples were analysed by a scanning electron microscope. Obtained results were statistically processed by Kruskal–Wallis and Mann–Whitney U-test (p < 0.05). Results. The most efficient system was PUI, with 66.7% of samples rated 1 and 33.3% rated 2. The next one was XP, and the least efficient was CSI, with 33.3% of samples rated 1 (resorptive defect without medicament). There was a statistically significant difference between the PUI and CSI systems (p < 0.05), while there was no difference between the PUI and XP systems. Conclusion. No system completely removed the CH from the simulated internal root resorption cavities. PUI was the most effective system for removing CH. The combination of techniques provides better performance in removing CH paste residues from the canal walls