Engineering Alloplastic Temporomandibular Joint Replacements

Temporomandibular disorders (TMD) are part of a heterogeneous group of pathologies that manifest with a constellation of signs and symptoms. They are the most frequent cause of chronic orofacial pain and are prevalent in 12% of the general population. Despite the debilitating nature of these disorders, there is no standardization for treatment of the diseased temporomandibular joint (TMJ). In this review, we present an overview of the functional anatomy of the TMJ and the engineering concepts that must be understood to better understand the indications for surgical management, the types of available treatments and the requirements for reconstruction. A comparison is made of the clinical outcomes with autogenous versus alloplastic reconstruction, including a history of alloplastic materials and the design features of currently available implants. Emphasis is made on material selection, modulus, stiffness, notch sensitivity and modularity. For the treatment of TMD, engineered TMJ alloplastic replacements have had considerable promise with additional room for improvement using new materials and recent design concepts.