(PO36) Minimally Invasive Removal of Root Canal Filling Material Aged for 64 Months from Minimally Instrumented Mandibular Molars

Abstract: This study aims to evaluate the effectiveness of combining the ProTaper Universal Retreatment system (PTUR) and XP-endo Finisher R instrument (XPFR) in removing aged root filling materials from minimally instrumented mandibular molars. Forty-eight mandibular molar canals with Vertucci’s type II or IV anatomy were instrumented to a size 20/.04 using Vortex Blue NiTi Rotary files and irrigated using the GentleWave system. They were then randomly divided into three groups based on the root filling method: single-cone with AH Plus sealer (SA), single-cone with GuttaFlow sealer (SG), or GuttaCore with AH Plus sealer (GA). Retreatment involved the PTUR system, followed by a supplementary XPFR approach for specimens with residual filling material. Micro-computed tomography was used to assess the volume of filling material in the canals after 64 months of obturation, post-PTUR retreatment, and after the supplementary XPFR approach. Post-PTUR retreatment, the volume of remaining root filling material did not significantly differ among these groups (p > .05). However, after supplementary XPFR instrumentation, the volume of remaining filling material significantly decreased in all groups (p < .05), with the PTUR and XPFR combination being most effective in the SA and GA groups, followed by the SG group. The combined use of PTUR and XPFR was effective in removing a significant amount of aged root filling material from minimally instrumented mandibular molars. The difficulty of removing filling material was higher in canals obturated using the single-cone technique with GuttaFlow sealer compared to those with the AH Plus sealer.