Effectiveness of Different Instruments in Removing Filling Materials from Oval Curved Root Canals

doi:10.13701/j.cnki.kqyxyj.2025.06.006

Abstract

Abstract: Objective: To compare the effect and centering ability of Protaper Universal Retreatment (PTUR), Reciproc Blue (RB), and Re Treaty (RT) nickel-titanium files in oval curved root canals using cone beam computed tomography (CBCT). Micro-computed tomography and scanning electron microscopy were also utilized to evaluate the effectiveness of classic syringe-based irrigation (CSI), passive ultrasonic irrigation (PUI), and the XP4 auxiliary file (XP4) in removing residual root filling materials and the smear layer. Methods: (1) Retreatment with Nickel-Titanium Files: Forty-five ex vivo single-root canal premolars, which had undergone complete root canal filling, were selected and randomly divided into three groups (n=15): PTUR, RB, and RT. The volume of remaining root filling material and any root canal deviation were recorded for each group. (2) Auxiliary irrigation experiment: Following retreatment with RB, another set of 45 ex vivo single-root canal premolars were randomly divided into three groups (n=15): CSI, PUI, and XP4. For each group, the volume of remaining root filling material and the score of the smear layer on the inner wall of the root canal were recorded. Results: (1) There was no significant difference in the volume of remaining root filling material between the three groups of re-treated nickel-titanium instruments (P=0.620). At 2 mm from the root apex, the apical transportation offset of the RB group was significantly smaller than that of the PTUR group (P=0.027). (2) Compared with CSI and PUI, XP4 removed significantly more root canal filling material (P＜0.001). In the middle and apical third of the root, the cleaning effect of the XP4 group on the smear layer was significantly better than that of the CSI group(P＜0.05). Conclusion: The PTUR, RB, and RT file systems are all suitable for the retreatment of oval curved root canals. Compared with PUI and CSI, XP4 significantly improves the removal of residual root filling material and smear layer after reprocessing with nickel-titanium mechanical instruments.

Key words: root canal retreatment, removal of filling material, root canal deviation, passive ultrasonic irrigation, micro-computed tomography

CHENG Yuqi, LIU Ruiru, SI Yawei, DUAN Ke, MA Rui, XIAO Yan. Effectiveness of Different Instruments in Removing Filling Materials from Oval Curved Root Canals[J]. Journal of Oral Science Research, 2025, 41(6): 482-489.

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