The success of complete removable dentures (CRDs) has traditionally been based on retention and stability. However, in the long term, occlusal balance plays a decisive role in preserving the integrity of the supporting tissues and ensuring functional comfort in the completely edentulous patient. Defective occlusion may lead to sometimes severe mucosal lesions, thereby compromising the longevity of prosthetic rehabilitation. To describe, through a clinical case, the repercussions of defective occlusion on the supporting tissues in a completely edentulous patient, and to illustrate the interest of occluso-tissue conditioning particularly through the use of the Tench articulation prior to the fabrication of new complete dentures. A completely edentulous patient, a long-term wearer of unstable and painful complete dentures, presented with functional discomfort and mandibular mucosal lesions. Clinical and occlusal examination revealed an underestimated vertical dimension, an incorrect centric relation, and anterior locking. A transitional phase of occluso-tissue conditioning using the existing dentures was implemented, combining occlusal rehabilitation through the Tench articulation with tissue conditioning. The gradual correction of occlusion and the improvement of the mucosal condition resulted in satisfactory tissue healing, restoration of occlusal parameters, and successful functional integration of the new complete dentures. Occluso-tissue conditioning represents a key step in the management of completely edentulous patients wearing defective complete dentures. The Tench articulation constitutes a reliable and conservative approach for restoring the vertical dimension and centric relation while using existing dentures as therapeutic tools.