Evaluación multimodal de tres Sistemas Rotatorios NITI: simulación clínica, pruebas mecánicas y análisis de elementos finitos.

Abstract

Introduction: This study aimed to compare the clinical durability, mechanical performance, and stress behavior of three NiTi rotary systems—BlueShaper (Blue), BlueShaper Pro (Dual Wire), and BlueShaper Gold; through a multimodal evaluation that included simulated instrumentation in 3D-printed replicas, mechanical testing, and finite element analysis (FEA). Methods: Sixty instruments (n = 20 per group) were tested. Simulated canal preparation was conducted in standardized 3D-printed mandibular molars with a 40° mesial root curvature until fracture occurred. Mechanical tests included torsional and flexural loading using a universal testing machine and stainless-steel blocks with a standardized 40° curvature. FEA simulations evaluated von Mises stress, shear stress, total deformation, cyclic fatigue behavior, and contact pressure between the instrument and canal wall. Results: BlueShaper Gold prepared an average of 9.5 canals before fracture, outperforming Pro (7.8) and Blue (6.8), with a 40% higher fatigue resistance than Blue (p <0.05). Gold also exhibited the highest torsional resistance (2.61 N·mm) and the lowest von Mises stress in flexural simulations (5571 MPa), indicating greater structural resilience. BlueShaper Pro demonstrated the longest TTF during fatigue testing (73.9 seconds) and total deformation in FEA (11.41 mm). In contrast, Blue showed 29% lower fatigue resistance, higher maximum stress levels (up to 5935.3 MPa), and greater strain localization, suggesting a higher risk of early failure despite identical geometry (p<0.05 in all comparisons). Conclusions: BlueShaper Gold exhibited the highest mechanical strength and fatigue resistance. BlueShaper Pro demonstrated the longest fatigue life and balanced mechanical behavior. BlueShaper showed the lowest performance across most parameters. The strong correlation among clinical, mechanical, and FEA data reinforces the critical role of alloy composition in determining instrument durability, even when design remains constant.