Collagen crimping in the intra-articular disc and articular surfaces of the human temporomandibular joint

The presence of crimping within soft fibrous connective tissues has a considerable role in determining the biomechanical properties of the tissue. However, there is little or no information on crimping of collagen in the human temporomandibular joint. To remedy this situation, the presence and nature of any crimping was studied in sections of human temporomandibular joints from individuals varying in age from between 4.5–63 years, using polarized light microscopy and differential interference contrast microscopy. The presence of crimping was looked for in collagen within the intra-articular disc and the articular surfaces of the mandibular fossa and mandibular condyle. By polarized light, crimping was seen throughout all three tissues at all ages studied. Quantification from micrographs enlarged to ×250 showed that the periodicity of the banding (representing half a complete crimp wave) had a mean varying between about 15–20 μm. Crimping was also directly visualized by differential interference contrast microscopy. The presence of such a fundamental feature needs to be considered when explaining the normal function of the temporomandibular joint.