Modulus of elasticity of human periodontal ligament by optical measurement and numerical simulation

Abstract

Objective: To determine the elastic modulus of the periodontal ligament (PDL). Materials and Methods: This study was carried out on eight human maxillary jaw segments containing central incisors. Displacements were measured under load using a laser sensing system, electronic speckle pattern interferometry (ESPI). Subsequently, finite element models presenting the same individual geometry as the respective autopsy material were developed by the software of Mimics and Ansys, based on scanning data from micro computed tomography (micro CT), to simulate tooth mobility numerically under the same force systems as were used in the experiment. Numerical force/deflection curves obtained from the models were fitted to the experimental curves by repeatedly calculating theoretical tooth deflections and varying the elasticity parameters of the human PDL. Results: A bilinear material parameter set was assumed to simulate tooth deflections. Mean values of E 1 = 0.04 MPa, E 2 = 0.16 MPa, and ultimate strain of ε 12 = 7.3% were derived for the elastic behavior of the PDL. Conclusion: Force/deflection curves from the measurements showed a significant nonlinear behavior of elastic stiffness of the PDL. A bilinear material parameter set was suitably assumed to be a description of nonlinear properties of the PDL. © 2011 by The EH Angle Education and Research Foundation, Inc.