Modern endodontics aims to treat or prevent apical pathology with a view to maintaining the tooth's long-term function. The root canal shaping technique, in synergy with pulp chamber opening, dramatically influences the residual structural integrity and the predictability of long-term clinical outcomes. A minimally invasive approach is considered essential for maximally preserving root dentin while avoiding potential microcracks. To this end, it is necessary to reduce the taper while fully respecting the original anatomy, developing a logical cavity preparatory to three-dimensional obturation techniques, while maintaining a minimal apical foramen to ensure effective irrigants. The B-4U system features a 05 taper and heat-treated NiTi alloy instruments with progressive taper, a rhomboid cross-section, and two cutting angles that allow for high elasticity and resistance to cyclic fatigue. This creates the foundation for the use of the most effective 3D obturation techniques: single cone and bioceramic, carrier-based, and warm GP condensation. The course's objective is to illustrate a predictable and minimally invasive shaping protocol that allows the practitioner to manage all endodontic anatomies with maximum safety, in synergy with the most modern obturation techniques.