2024 Volume 36 Issue 2 Pages 68-75
The pathophysiology of temporomandibular joint (TMJ) disorder (TMD) varies. However, most cases result from structural changes in the articular TMJ disc. In advanced cases, prolonged TMD results in perforation or rupture of the TMJ disc, as well as bone and cartilage deformities. Although the cause of TMD remains unclear, it may be due to an imbalance between the microenvironment and the host adaptive capacity, and mechanical load-related factors and estrogen have been implicated. Joint tissues are rich in extracellular matrix, which have viscoelastic properties and a lubricating function against frictional forces. When the mechanical load applied to joint tissues exceeds the physiological limit, the metabolic balance is disrupted and bone and cartilage tissues are destroyed. However, the relationship between mechanical loading and estrogen during the process of such destruction is unknown. Excessive mechanical stress may decrease the levels of lubricating proteins, thereby increasing the levels of substrate-destructive proteins, resulting in substrate destruction. Intra-articular injection of high-molecular-weight hyaluronic acid has been reported to alleviate such substrate destruction in orthopedics. However, there is insufficient evidence to support its efficacy in the TMJ. In this article, we review these issues with reference to the results of previous studies and our own research.
