Figure 4.

Cyclic ultra micro-indentation superior surface mechanical characterization.
The micro-indentation methodology is illustrated in: (A) describing loading [1], holding [2], and unloading [3] then repeating for 5 cycles to obtain steady state mechanical properties [4] of the TMJ disc.
Mechanical characterization of the surface, subsurface, and helical bundles layers are described in (B) and (C).
Although five micro-indentation depths were tested (numbers 1 to 5) three distinct mechanical regions have been separated in (B) depicted by loops a-b, c-d, e-f, with loop a-b exhibiting the greatest resistivity to loading and loops c-d and e-f representing the surface regions with the greatest energy dispersion (hysteresis).
The hysteresis loops correlate to the steady state compressive modulus of elasticity data shown in (C) (n = 6, *P ≤ 0.01).