(PR18) Evaluation of Efficacy of Different Rotary Instrument Systems for Gutta Percha Removal During Root Canal Retreatment

Abstract:

Objectives: To evaluate the efficacy of three different retreatment rotary file systems for removal of gutta-percha in single rooted premolar teeth. METHODS AND MATERIALS: Thirty extracted single-rooted human premolars were used. Root canal preparation done using ProTaper Gold rotary. All canals prepared to an F3 file. Obturation with ProTaper Gold (F3) gutta-percha cones, zinc oxide eugenol sealer and warm vertical compaction technique. Teeth were randomly divided into three experimental groups for retreatment: (Group 1) Hyflex Remover files, (Group 2) ProTaper Universal Rotary File - Retreatment, (Group 3) EndoRestart files. Roots were grooved longitudinally using a diamond disk and split using a rongeur into halves. Samples were examined under an operating endodontic microscope (Global) at 8X magnification. After being photographed with a digital camera, the images were evaluated by 3 independent pre-calibrated examiners blinded to group assignment. The amount of residual filling material was scored according to Ezzie et al.'s criteria.

Results: Data was analysed using nonparametric ANOVA and the Kruskal Wallis test. Preliminary results suggest a statistically significant difference between at least two rotary files. The Dwass, Steel, Critchflow-Fligner post-hoc procedure showed Group 1 and 2 had no statistically significant difference, but both performed better than Group 3 which was statistically significant.

Conclusion: Hyflex and ProTaper files performed similarly. Both removed more gutta percha and sealer than EndoRestart files.