Impact of Instrumentation Technique on Endodontic Treatment Quality in Curved Molars: A Retrospective Analysis

This cross-sectional study evaluated technical failures in root canal treatments (RCTs) of curved molars (> 10°) performed by undergraduate students and their association with instrumentation techniques. Evaluations included filling extension, density, taper and ledge/zip formation. Bivariate analysis (chi-square, 5% significance) calculated odds ratios (OR) and 95% confidence intervals (CI). Among 188 RCTs, manual instrumentation had higher risks of ledge/zip formation, inadequate density, taper and underfilling, while reciprocating techniques showed more overfilling. Root curvature did not influence failure rates. The study showed 100% power for detecting underfilling, inadequate density and taper; 97.98% for overfilling and 71.11% for ledge/zip formation. Instrumentation technique significantly impacted failure frequency, with manual techniques associated with more complications.