The Role of Matrix Metalloproteinases in Orthodontics, Dental Trauma, Restorative Dentistry, and Endodontics: Molecular Mechanisms and Clinical Implications.

Matrix metalloproteinases (MMPs) are zinc-dependent proteolytic enzymes involved in extracellular matrix remodelling in oral and dental tissues, including the periodontal ligament, alveolar bone, dentin, dental pulp, and periapical tissues. This narrative review summarises selected evidence on the role of MMPs and tissue inhibitors of metalloproteinases (TIMPs) in orthodontic tooth movement, dental trauma and root resorption, restorative adhesive dentistry, and pulp/periapical disease. Particular attention is given to signalling pathways that regulate MMP/TIMP activity, including nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), Wnt/β-catenin, and transforming growth factor beta (TGF-β)/Smad-related mechanisms. The review also discusses the biomarker potential and translational status of MMP-targeted strategies. Across clinical contexts, MMP activity contributes to both matrix degradation and tissue repair, and its biological effect depends on local stimuli, TIMP-mediated regulation, pathway crosstalk, and the stage of disease or treatment.