INTRODUCTION: the maximum removal of root canal filling material is essential for successful endodontic retreatment.
OBJECTIVE: to compare the efficacy of two reciprocating systems Reciproc (VDW, Munich, Germany) and WaveOne (Dentsply Maillefer, Ballaigues, Switzerland), compared with (NiTi) rotary system (ProTaper Universal Retreatment, Dentsply Maillefer) in the removal of root canal filling material
METHODS: Thirty messiobuccal canals of mandibular first molars were prepared using NiTi Revo-S (Micro-Mega, France) until SU file and then obturated. The specimens were divided into 3 groups (n=10) according to the system used for filling removal: group 1: Reciproc R25, group 2: WaveOne primary file, and group 3: ProTaper Universal retreatment rotary system. Cone beam computed tomography (CBCT) was used to scan the specimens before and after retreatment to measure the volume of filling material by using (Osirix 32-bit) software. Kruskal-Wallis test was used while the Wilcoxon test was used to test for changes of median volume before and after intervention. The Friedman test was used for all groups to test for differences of volume (%) of filling material remaining between the coronal, middle and apical zones
RESULTS: All teeth examined had filling remnants within the canals. No statistically significant differences (P> 0.05) in residual filling material were observed among the groups, with 11.03% in (Group 1), 6.80% in (Group 2), and 10.15% in (Group 3). ProTaper Universal retreatment system left more remnants in the apical part with no significant difference between groups (P>0.05).In the middle part, the Reciproc group had higher remnants than the other groups with significant difference between them
(P<0.05).Coronally, WaveOne left less remnants with no significant difference between the groups.
CONCLUSION: The Reciproc and WaveOne reciprocating systems were as effective as the ProTaper Universal retreatment system for root canal filling material removal although the WaveOne system appeared to give the best results.