An investigation of the viscoelastic properties of the periodontium in monkeys

Abstract

The non‐linear response of the tooth to external stresses is due to the interaction of the fibrous, cellular and vascular elements of the supportive tissues. In this study the relaxation of the central incisors after the suden removal of axial forces of 2.5 Newton was investigated in three monkeys. The displacement‐time curve was analysed using a technique of exponential curve fitting. Analysis shows that the periodontium is viscoelastic in nature and may be represented by three and possibly five Voigt elements. Comparison of the upper and lower incisors indicate that while the same basic processes are active in both mandible and maxilla they are different in magnitude. In the case of the fastest acting Voigt element the response is more rapid for lower teeth than for upper ones, corresponding either to less damping or a stronger spring constant. This difference in magnitude is presumably due either to differences in the architecture of the periodontium and alveolar bone or to the local blood supply. The authors are indebted to Dr. M. Braden of the London Hospital Medical College for his advice and guidance. Thanks are due also to members of the Department of Medical Physics of the University College Hospital, particularly Mr. J. S. Clifton for his encouragement, Mr. M. Conway and Mr. R. Favre for the construction of the force applicator and Mr. K. J. Cassell for his assistance.

Determination of the Mechanical Properties of the Periodontal Ligament in a Uniaxial Tensional Experiment

“…As is known from the literature, tooth movement under external forces shows nonlinear and time-dependent material behavior [1,14,16,17,22,23]. This behavior results from the material properties of the periodontal ligament, since the elastic modulus of tooth and bone is 1,000-10,000 times greater than that of the periodontal ligament [2,21].…”

“…A higher proportion (ca. 50-75%) of the periodontal ligament consists of collagen fibers [22] which have an important influence on the mechanical properties of the tissue due to their high fiber density and their spatial configuration [9]. Most of the collagen fibers are arranged in bundles extending from the cementum to the alveolar bone in a complex three-dimensional network [19].…”

Experiments to Determine the Material Properties of the Periodontal Ligament

“…He found in all experiments an increased tooth mobility until a limiting curve was reached. The influence of the loading history was also studied by Wills et al [24] using consecutive Schlussfolgerung: Die experimentellen Ergebnisse dienen zur Charakterisierung des Gewebes und damit zum Verständnis der Biomechanik der initialen Zahnauslenkung unter einer äußeren Belastung.…”

A discrete spectral analysis for determining quasi-linear viscoelastic properties of biological materials

“…The Fung quasi-linear viscoelastic (QLV) model is a standard tool for representing the nonlinear history-and time-dependent soft-tissue viscoelasticity of biological tissues [1][2][3][4]. The QLV model provides a simple fit to stressrelaxation tests, which are preferred over standard rotational rheometry for biological tissues due to issues of gripping and anisotropy.…”