Mechanical stiffness of TMJ condylar cartilage increases after artificial aging by ribose

Abstract

The present model, in which ribose was used to mimic certain aspects of age-related changes, can be employed as an in vitro model to study age-related mechanical changes in the TMJ condyle.

Aging does not change the compressive stiffness of mandibular condylar cartilage in horses

“…3). We previously showed that incubation of porcine TMJ condyles with ribose as an aging-effect simulation increased Pen level and consequently the stiffness of the cartilage 28 . Positive correlations between Pen increase on stiffening of cartilage has been also shown in natural aging both in hyaline cartilage and in fibrocartilage of TMJ disc form different species 6,14,29 .…”

“…The origin of the seemingly contradictory findings could be related to several parameters that have changed with aging, e.g., Pen level, GAG, and the region of the cartilage. Firstly, in a previous study, we measured a 50 fold increase in Pen levels leading to a 1.5 fold increase in stiffness 28 . The crosslink level of naturally aged samples in this study was only 15-fold higher than the young samples.…”

“…And finally, TMJ cartilaginous matrix dynamically changes to adapt to loading with aging 4 . TMJ condylar cartilage undergoes diverse loading patterns in different regions which results in regional-dependent stiffness 16,28 . Each region might change differently with aging.…”

“…To determine the stiffness of the central region of the intact condyle, cyclic unconfined compression loading tests were performed by using a custom-made instrument as described previously 28 . Briefly, a solid cylindrical indenter (diameter 4 mm) applied strain-control cyclic displacements of the cartilage and simultaneously the compressive reaction force was recorded.…”

“…Therefore, steady state modulus (E St ) was calculated from the peak force average of the last five loading cycles. As compressive stiffness is different topographically across the condyle 28 , only the central region was tested from all the condyles. The stiffness of right and left condyles of each head were averaged and reported for each age.…”