Comparison of different methods removing guttapercha+guttasealer during retreatment of root canal

Abstract

Introduction: Retreatment of a root canal in the case of infection requires complete removal of previous filling material. Several techniques have been proposed to remove filling materials from root canal system, including the use of endodontic hand files, Nickel Titanium rotary instruments, ultrasonic and use of adjunctive solvents. Aim of the study was to evaluate and compare the efficacy of different methods for root canal filling material removal. Methods: Seventy-five extracted human premolars were prepared using a crown-down technique and filled with gutta-percha (guttasealer). Teeth were radiographed to confirm the adequacy of the root canal obturation. All teeth were stored at 100% humidity and 37°C for six weeks. After that, the specimens were divided randomly into three experimental groups with 25 teeth. Group 1, retreatment was done using ProTaper retreatment and hand files, in Group 2 using Ultrasonic retreatment tip and hand files, and in Group 3 using hand files with Endosolv solvent respectivety. The retreatment time was recorded for each tooth using a stopwatch. Teeth were grooved longitudinally with diamond disk in bucco-lingual direction and split into two halves with a chisel. Then the specimens were examined under digital microscope, assessed using AutoCad 2019 software and percentage of remaining filling material in coronal, middle, apical thirds of canal calculated in mm2. The data was analyzed by ANOVA and Kruskall-Wallis test. Result: Canal filling material removal time was shorter for endosolv solvent and hand files than ProTaper retreatment +hand files and ultrasonic retreatment tip+hand files. The average percentage of remaining gutta-percha and guttasealer was 9.42% in group1, and 9.00% in group2, and 12.99% in group3. Conclusion: The ProTaper retreatment +hand files and ultrasonic retreatment tip+hand files groups had less percentage of residual gutta-percha and guttasealer materials, but endosolv solvent and hand files had significantly shorter operating time with a comparing to the other groups.