Comparative Evaluation of Vertical Fracture Resistance and Retrieval Outcomes Using Ultrasonic, LeoPen Loop, and XP-Endo Shaper Systems: An In Vitro Study

Background Separated endodontic instruments are a frequent procedural challenge that can compromise treatment outcomes. Retrieval techniques vary in efficiency and may influence root integrity. This study compared the impact of three retrieval systems—ultrasonic tips, LeoPen loop, and XP-Endo Shaper—on vertical fracture resistance (VFR), retrieval time, and retrieval success. Methods Twenty-seven extracted human mandibular molars with moderately curved mesial roots (15–30°) were randomly allocated into three groups (n = 9): Ultrasonic Tip (Ed4), XP-Endo Shaper, and LeoPen Loop. A 4 mm NiTi fragment was fractured in the middle third of each canal. Retrieval was performed under magnification, and success (yes/no), retrieval time (min), and post-retrieval VFR (N) were measured using a universal testing machine. Data were analyzed using one-way ANOVA and Fisher’s exact test (α = 0.05). Results The LeoPen Loop system achieved the highest retrieval success (88.9%), followed by ultrasonics (66.7%), while the XP-Endo Shaper had the lowest (11.1%) (FEp = 0.001). Mean ± SD retrieval times were 25.4 ± 8.8 min, 24.0 ± 7.7 min, and 19.8 ± 5.6 min, respectively (p = 0.11). Mean ± SD VFR values were 711.8 ± 230.1 N (ultrasonic), 730.4 ± 241.0 N (XP-Endo Shaper file), and 710.0 ± 215.3 N (LeoPen), showing no significant differences (p = 0.95). A weak, non-significant correlation existed between retrieval time and VFR (r = − 0.13, p = 0.53). Conclusions All three systems preserved comparable vertical fracture resistance. The LeoPen Loop achieved the highest retrieval success with minimal complications, making it a reliable and conservative technique for removing separated instruments from moderately curved canals. Ultrasonic retrieval remains effective when applied carefully, whereas the XP-Endo Shaper demonstrated limited success in this context.