This lecture presents a critical analysis of three clinical cases managed through a multidisciplinary approach integrating orthodontic, orthognathic, periodontal, and restorative treatments. The aim is to demonstrate how, despite the application of state-of-the-art protocols across the different disciplines involved, the final outcome may still be influenced by intrinsic structural limitations that cannot be completely overcome. Particular attention will be given to the constraints imposed by the craniofacial skeletal pattern, orofacial musculature, and specific anatomical characteristics, all of which may represent biological boundaries beyond which even the most advanced therapeutic techniques cannot achieve absolute occlusal, functional, and esthetic ideality. The cases will also be discussed in light of the "fourth dimension"—time—through a follow-up period exceeding five years, allowing assessment of treatment stability, biological adaptation, and the consistency between the original treatment objectives and the long-term clinical outcomes. The presentation will therefore focus not only on the possibilities offered by contemporary multidisciplinary orthodontics but also on the importance of recognizing and respecting the anatomical and biological limits that continue to play a fundamental role in defining realistic and sustainable treatment outcomes.