|3048 Dynamic properties of bovine temporomandibular joint disks with age|
E. TANAKA, J. AOYAMA, K. HANAOKA, M. WATANABE, H. MURATA, T. HAMADA, and K. TANNE, Hiroshima University Faculty of Dentistry, Japan|
In histological and biochemical aspects, the temporomandibular joint disk exhibits age-related changes. However, age-related changes in the dynamic mechanical property of the disk remain unclear. Objectives: The aim of this study was to evaluate the age-related changes in the dynamic viscoelasticity of bovine temporomandibular joint disk. Materials and Methods: Thirty-six disks from young-adult (n=12), adult (n=12) and mature-adult cattle (n=12) were used for dynamic indentation tests. Each disk was cut into anteroposterior sections, and the specimen derived from the central region was subjected to the experiment. Dynamic viscoelastic properties of bovine disks were determined using an automatic dynamic viscoelastometer, Rheovibron. During the measurement, dynamic tensile force was applied to the specimen by sinusoidal strain with administrative strain of 0.5%. The oscillation frequency was ranged from 0.1 to 100 Hz. Results: The magnitude of complex modulus, the storage modulus and the loss modulus increased as the frequency increased from 0.1 to 100 Hz, although the young-adult group presented relatively small changes. The mature-adult disk had greater values of these moduli than the remaining disks. The loss tangent ranged from 0.1 to 0.3, which means that the disk is mostly elastic with relatively small viscosity. Conclusions: It is shown that the older specimens exhibited higher moduli than the younger ones. It is thus assumed that older disks may have a greater capacity for distributing stress and preventing transmission of the applied load to the glenoid fossa, eliminating a reduction of stress concentration.
|Seq #275 - TMJ - Structure and Function II|
3:45 PM-5:00 PM, Friday, 8 March 2002 San Diego Convention Center Exhibit Hall C