The collagen fibers and proteoglycans in the disc of temporomandibular joint provide resistance to various loadings. Thus far, however, the role of the proteoglycans in determining the viscoelastic properties of the disc has not been investigated. In the present study the hypothesis was tested that the viscoelastic behavior of the disc decreases by the removal of proteoglycans. In 32 bovine discs, dynamic tensile tests with a wide range of frequencies were performed. Before testing, specimens were treated with different concentrations of alpha-amylase to remove proteoglycans. As the frequency increased from 0.1 to 100 Hz, the disc became more viscoelastic. Increasing the concentration of alpha-amylase significantly decreased its viscoelasticity. It was concluded that proteoglycans play an important role in determining the viscoelastic properties of the disc and, therefore, give the disc a greater capacity for distributing and reducing stresses.
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