Dynamic viscoelastic behavior of bovine periodontal ligament in compression

Abstract

Background and Objective As the main connector of teeth to the surrounding bone, the periodontal ligament (PDL) plays an important role in absorption and distribution of physiological and para‐physiological loading. Despite the difference in the mechanical response of the PDL in tension and compression, little information is available on its viscoelastic behavior in compression. To explore the contribution of the fluid phase of the PDL, the aim of the present study was to measure its nonlinear time‐dependent behavior in compression. Material and Methods The in vitro dynamic compressive tests were carried out over a wide range of frequencies at three different preloads. Also, a generalized Maxwell model was proposed based on the experimental data to develop a viscoelastic model for subsequent computational analysis of the PDL. Results The higher values of loss factor in compression found in the range of 0.03‐0.4 than those of 0.04‐0.08 reported in tension, implies the focal role of the fluid phase in compressive dynamic response. Furthermore, the model parameters predicted that with an increase in preload, the role of the viscous components decrease, whereas the role of the elastic component increases. Conclusion The viscous effect of the PDL in compression is greater than that in tension. Also, the dependence of the relaxation modulus of the bovine PDL on the applied load indicates its nonlinear viscoelastic behavior in compression.

Engineering Ligament Scaffolds Based on PLA/Graphite Nanoplatelet Composites by 3D Printing or Braiding

“…The storage modulus achieved for the 3D-printed scaffolds is in the same order of magnitude of the dynamic mechanical response reported for ligaments under compression at 1 Hz [55]. M. Najafidoust et al [55] performed dynamic compression mechanical tests in ligaments in a wider range of frequencies (0.01-100 Hz) and at three different preloads (0.25, 0.75, and 2 N). An increase in the storage modulus was observed with increasing preload.…”

In situ AFM-based nanoscale rheology reveals regional non-uniformity in viscoporoelastic mechanical behavior of the murine periodontal ligament

“…A few recent studies have also investigated compressive function in human PDL demonstrating vast heterogeneity within and between specimens as well as directionallydependent viscoelastic behavior (Najafidoust et al, 2020;Wu et al, 2020), but these studies were performed by indenting along the long axis of the PDL rather than in the transverse direction as in this study. Regardless, dynamic testing pointed to a dominance of interstitial fluid flow in the mechanical response, similar to that of a biphasic material like articular cartilage and to what we have reported.…”

Modelling and evaluating periodontal ligament mechanical behaviour and properties: A scoping review of current approaches and limitations

“…24,27 Further, non-linear models allow for investigation of additional critical properties, such as creep, non-linear load-displacement nature and time-dependent anisotropic mechanical behaviour. 24,27,28,47 Different loading regimes such as nanoindentation 28 and compression 48 may be used to elucidate a fuller understanding of the material response under complex loading. For instance, compressive loading coupled with a generalized Maxwell model has been used to understand the role of the fluid phase in compressive dynamics of the PDL and a dynamic shear creep experiment has identified promising new insights into the viscoelastic fluid characteristics of the PDL.…”