Poster 2: Cell and Tissue Studies

Annie Porter, Jonathan Kim, Lin Han, Drexel University; John Peloquin, Michael Santare, X. Lucas Lu

University of Delaware, Drexel University

Disorders of the temporomandibular joint (TMJ), the only moving joint in the human head, affect over 10 million Americans. TMJ condylar cartilage however remains an understudied tissue. It has a unique, bi-layered structure in which the top layer is fibrocartilage and the bottom layer is primarily hyaline cartilage. The layers are integrated by collagen bundles which extend from the top surface and root into the subchondral bone. In this study we hypothesized that the unique bilayer structure endows the TMJ condylar cartilage with a low dynamic stiffness, especially under small stress and high frequency loads, to minimize the impact on the brain from TMJ daily functions, i.e., eating and talking. At low stresses, the dynamic modulus of TMJ cartilage was lower than that of the knee. This trend implies that during daily activities, such as talking, TMJ cartilage provides better shock absorption than knee cartilage, potentially reducing impact on the brain. It is critical to note that the dynamic moduli here were obtained when the knee and TMJ tissues were under the same initial load, but different initial strains. Thus, the dynamic moduli of TMJ could be even lower than the knee with similar initial strain.

Research Area: Cartilage