Characterization of Xenogenic Biologic Scaffold for the Temporomandibular Joint Disc

Objective: Porcine derived extracellular matrix (ECM) has been successfully used as a biologic scaffold material for numerous soft tissue applications. The ability of an ECM scaffold manufactured from porcine urinary bladder matrix (UBM) to support the complete replacement of a temporomandibular joint (TMJ) disc in a canine model was determined.

Method: A novel design consisting of particulate UBM-ECM compressed between two sheets of the same ECM material in the approximate configuration of the native TMJ disc was used as a unilateral replacement following bilateral excision of the native TMJ. The contralateral side served as an untreated control. After six months, the remodeled scaffold materials were surgically excised with the adjacent articular surfaces of the temporal bone and mandibular condyle.   Histologic examination with immunolabeling for endothelial cells and macrophages was performed.  The mechanical behavior of the tissue under compression was modeled using the transverse isotropic biphasic theory.  The collagen, glycosaminoglycan (GAG), and DNA content of the tissue was also determined.

Result: Results showed the histologic appearance of the remodeled ECM to be indistinguishable from the native TMJ disc.  The compressive data fit the transversely isotropic biphasic model well. Biomechanical and biochemical studies showed an almost complete transition from the properties of the ECM material to the properties of the native fibrocartilaginous disc. The contralateral (untreated) TMJ showed severe articular surface degeneration. The articular surfaces of the side with the ECM implant showed minimal degenerative change.

Conclusion: We conclude that porcine derived UBM-ECM can support the formation of a neo-TMJ disc in this dog model.