Geometric response of curved mandibular molars to NiTi instrumentation

Preserving root canal geometry in curved canals remains a major challenge during mechanized NiTi instrumentation. Therefore, it is of interest to evaluate the shaping performance of HyFlex EDM, TruNatomy and XP-Endo Rise in curved mesiobuccal canals using high-resolution micro-computed tomography. Thirty extracted mandibular first molars with 15°C-35°C curvature were allocated into three groups (n = 10) and canal transportation and centering ability were assessed at 3, 6 and 9 mm from the apex. XP-Endo Rise showed minimal buccolingual but increased mesiodistal transportation, whereas TruNatomy demonstrated superior centering with minimal canal deviation and HyFlex EDM exhibited balanced shaping behavior. All systems maintained root canal geometry within clinically acceptable limits.