| Popis: |
We hypothesize that the presence of in-folding in a filled mammary shell leads to shortening of the time to failure under tensile fatigue. Specimens, cut from pristine shells, were mounted in S-folded, creased, and unfolded configurations. A characteristic change, occurring in a transmembrane capacitance-proportional alternating current (AC) signal, which was used to monitor working of each specimen, was chosen as a robust marker that preceded frank shell perforation. Subjecting all specimens to stringent, controlled conditions led to time-to-fatigue failure estimates that demonstrated an order-of-magnitude reduction in lifetime for the folded specimens when compared with that for pair-matched, unfolded specimens. Creases also reduced the fatigue lifetime, but not to the degree that folds did. Observations based on the experimental behavior of folded shell material provide possible mechanisms for the potential lifetime clinical reduction of in-folded implants as well as for the development of silicone-on-silicone abrasive wear and generation of debris. |
