Biomechanical behavior of the temporomandibular joint disc

The temporomandibular joint (TMJ) disc is a poorly understood tissue that is commonly subjected to pathologies that can lead to a locked jaw and severe pain, making daily activities such as talking, laughing and eating almost unbearable. Tissue engineering is a potential treatment for various pathologies of the TMJ disc. Unfortunately, there are few basic characterization studies describing the disc at the biochemical, biomechanical and cellular level. This study aims to provide a description of the biomechanical behavior of the TMJ disc to serve as a ´gold standard´ for tissue engineering studies. The disc was tested to failure under uniaxial tension in two directions, mediolateral (ML) and anteroposterior (AP), and in 3 locations per direction. In the ML direction, the posterior band was stiffer and stronger than the anterior band, which was in turn stiffer and stronger than the intermediate zone. The posterior band was the toughest region and the intermediate zone had a significantly higher failure strain. In the AP direction, both the central region and medial region were stiffer and stronger than the lateral region, although similar to each other. However, there was no significant difference between these three regions for energy and strain to failure. Comparison to our previous compression study of the TMJ disc revealed the disc is dramatically stiffer under tension than compression.