Efficacy of Passive Ultrasonic Activation Assisted Hand vs. Rotary Retreatment Files in the Removal of Root Canal Filling Material: An In Vitro Study

Abstract

Introduction: Endodontic treatment failures are caused by persistent or secondary intraradicular infection due to inefficient treatment or re-infection of the obturated root canal system because of coronal or apical leakage. Complete removal of Gutta-Percha (GP) from the root canal system is essential during retreatment procedures in order to re-establish healthy periapical tissues. Many techniques and materials have been advocated in root canal-treated teeth to remove the obturating materials. However, residues of the filling materials have been observed on the canal walls in all the techniques. Therefore, this study was designed to explore the application of passive ultrasonic activation in the removal of gutta-percha and epoxy resin based root canal sealer during endodontic retreatment by rotary and hand instruments. Aim: To evaluate the efficacy between passive ultrasonic activation assisted hand vs. rotary retreatment files in the removal of gutta-percha and sealer during endodontic retreatment. Materials and Methods: The current study was an experimental in vitro study where all the procedures were carried out in extracted human teeth from October 2018 till February 2019. Forty extracted human single rooted teeth were selected. The root canals were prepared using ProTaper Next rotary files and obturated by a hybrid warm gutta-percha technique. They were divided into four groups of ten specimens each based on the retreatment procedures: Group 1: H-files, Group 2: H-files and passive ultrasonic activation of xylene, Group 3: ProTaper Universal retreatment files and Group 4: ProTaper Universal retreatment files and passive ultrasonic activation of xylene. The specimens were sectioned buccolingually after retreatment procedure and viewed under stereomicroscope for evaluating the percentage of remaining gutta-percha. Data obtained was subjected to Normality tests. Further statistical analysis was done using one-way ANOVA followed by Tukey Kramer Test for pairwise comparisons. Results: Irrespective of the technique, all the specimens showed residual filling materials on the canal walls. ProTaper Universal retreatment files with or without ultrasonic activation of solvent showed significantly (p<0.05) less filling material remnants when compared to H-files with/without ultrasonic activation of solvent. Conclusion: Rotary instrumentation supplemented with passive ultrasonic activation was found to be more efficient in removing root canal filling materials.

Keywords

• protaper retreatment files
• root canal treatment
• solvent
• ultrasonic irrigation