Cluster-net structured polymer hydrogel elastomer engineered as artificial temporomandibular joint disc for establishing mechanical homeostasis

Temporomandibular joint disorder (TMD) related to temporomandibular joint (TMJ) disc involves a large number of patients worldwide. Artificial TMJ disc replacement represents a promising therapeutic intervention for advanced TMD cases. However, the TMJ's complex biomechanical environment-characterized by high-frequency gliding and rotational movements-imposes stringent demands on artificial disc materials. To address this challenge, a cluster-net structured composite material is developed, comprising water-based polyurethane (WPU) reinforced with polyvinyl alcohol (PVA) hydrogel. This design simultaneously optimizes mechanical strength, friction resistance, and fatigue endurance. The cluster-net architecture strategically segregates structural support and energy dissipation functions: WPU clusters absorb strain energy via conformational changes, thereby shielding the PVA networks from fatigue-induced damage. In a minipig model with total TMJ disc defects, multiscale analyses demonstrate the WPU/PVA disc's efficacy in mitigating cartilage matrix degradation and guiding subchondral bone remodeling. With its high clinical translational potential, this composite disc offers a novel therapeutic strategy for severe TMD cases, while also establishing a conceptual framework for reconstructing load-absorbing cartilage structures in other synovial joints.