Vergleichende Studie der Effektivität vier verschiedener Spültechniken zur Entfernung von Kalziumhydroxid aus einem gekrümmten Wurzelkanalsystem

Abstract

Introduction: The aim of this study was to compare the effectiveness of different irrigation techniques on the removal of calcium hydroxide from curved root canals with the focus on the angle and radius of curvature. Methodology: One-hundred extracted human mandibular molars with angles of curvature of 20 to 50 degrees and radii of curvature of 1 to 16 mm were selected. To determine the angle and radius of curvature the method described by Pruett et al. (1997) was used. The 100 mesiobuccal root canals were prepared to size 02/35 and were randomly divided into 5 groups (n=20). The root canals were completely filled with calcium hydroxide. The homogeneity of the calcium hydroxide was verified radiographically. After storing for 7 days at 37°C and 100% humidity the teeth were irrigated. Irrigation was performed for 6 x 30 seconds with 18,6 ml aqua dest with ultrasonic irrigantion (group 1), RinsEndo® (group 2), CanalBrush™ (group 3), Endo-Activator® (group 4) and manual irrigation (group 5 = control). After irrigation the roots were split longitudinally in buccal-lingual direction. The root canals were examined under a microscope and the amount of remaining calcium hydroxide was scored using a modified five-grade scoring system (Lambrianidis et al., 2006). The data were analyzed with a non-parametric statistical test. Results: None of the used techniques were able to remove calcium hydroxide completely from the root canals. Ultrasonic irrigation, RinsEndo®, CanalBrush™ and Endo-Activator® reached nearly the same results, but ultrasonic irrigation in average showed the best outcome. Manual irrigation performed significantly worse than the other systems. Significant effects of the angle and radius of curvature on the results were detected. With increase of radius of curvature or with decrease of angle of curvature all irrigation techniques showed worse outcomes. Further on the irrigation efficacy was significantly higher in the curved middle part than in the apical part of the root canals. Conclusion: During endodontic treatment the individual angle and radius of curvature should be considered in the selection of the optimal irrigation technique. Ultrasonic irrigation showed by trend the best results in removing calcium hydroxide from curved root canals, but the differences between the systems tested were not significant. Manual irrigation performed significantly worse than the other systems.