Comparison of the Different Irrigation Activation Techniques for Supportive Removal of Root Canal Filling in Retreatment

Objectives: The aim of the this study was to assess the effectiveness of XP-endo Finisher, EndoActivator, Er, Cr: YSGG laser active irrigation, passive ultrasonic activation techniques in removing filling remnants from the root canals after root canal retreatment procedures.
Methods: Seventy five single-rooted mandibular premolar teeth were instrumented with Resiproc 40 (# 40.06) instruments and obturated with gutta-percha and AH Plus sealer using the continuous wave of condensation technique. After storage at 37 °C and 100% humidity for 1 week, the specimens were retreated with the ProTaper Universal Retreatment and ProTaper Next (X2-X5) NiTi instruments for the removal of filling material. Then teeth were randomly divided into five groups (n = 15), and the activation processes were applied: Group 1. conventional needle irrigation, Group 2. EndoActivator, Group 3. passive ultrasonic activation, Group 4. XP-endo Finisher and Group 5. Er, Cr: YSGG laser active irrigation. Conventional needle irrigation was used as the control group. The teeth were sectioned and steromicroscopy images were taken. The images were analysed using Image J software regarding the area of residual root filling. In addition, a scanning electron microscope images were taken from 3 samples from each group. Oneway ANOVA, Tukey, Wilcoxon and Friedman tests were performed for statistical analysis.
Results: The filling materials removal efficacy in the apical region and the total canal area; the XP-endo Finisher, EndoActivator, passive ultrasonic activation groups were superior to conventional needle irrigation group (P < 0.05) and there was no statistically significant difference between the conventional needle irrigation and Er, Cr: YSGG laser active irrigation groups (P > 0.05). There was a statistically significant difference between the Er, Cr: YSGG laser active irrigation group and passive ultrasonic activation groups in total canal area (P <0.05). In middle and coronal region of the root canal; the conventional irrigation group remove less filling material then other groups (P < 0.05) and there was no statistically significant difference between the other groups (P> 0.05).
Conclusions: In all groups, there is residual substance in the root canals. The apical regions of the canals contain more residual filling than the middle and coronal regions.