Comparison of the ultrasonic, Masserann, and BTR-pen techniques for removing fractured instruments with dental microscope: a CBCT-based in vitro study

OBJECTIVE: This in vitro study compared the efficacy, dentin loss, and outcomes of ultrasonic, Masserann, and Broken Tool Remover Pen (BTR-Pen) techniques for removing fractured endodontic instruments using cone-beam computed tomography (CBCT) analysis. MATERIALS AND METHODS: Ninety extracted single-rooted teeth were randomly allocated into three groups (n = 30). ProTaper F2 instruments were intentionally fractured in the middle third of each canal, creating 3-4 mm fragments. Removal was performed using ultrasonic tips, Masserann trephine burs, or the BTR-Pen loop system. CBCT scans quantified dentin loss. Success rates, removal times, and complications were analyzed using one-way analysis of variance, Tukey honestly significant difference, chi-square, and likelihood-ratio chi-square tests (p < 0.05). RESULTS: Ultrasonic removal showed the highest success rate (90.0%), followed by BTR-Pen (86.7%) and Masserann (70.0%). Pairwise likelihood-ratio chi-square analysis showed lower success for Masserann than ultrasonic removal (p = 0.049). Masserann caused significantly greater canal volume increase (4.50 ± 0.50 mm³) than ultrasonic (0.75 ± 0.30 mm³) and BTR-Pen (0.93 ± 0.40 mm³) techniques (p < 0.001). Ultrasonic removal required the shortest time (110.0 ± 35.0 s), followed by BTR-Pen (213.4 ± 40.0 s) and Masserann (240.0 ± 50.0 s). CONCLUSIONS: Ultrasonic and BTR-Pen techniques achieved high success with better dentin preservation than Masserann. When retrieval is indicated, techniques that maximize dentin preservation should be preferred to reduce the risk of root weakening and procedural complications.