Modeling the biomechanics of the mandible: A three-dimensional finite element study

Hart, Richard T.; Hennebel, Vincent V.; Thongpreda, Nisra; Buskirk, William C. Van; Anderson, R.C.

doi:10.1016/0021-9290(92)90025-v

Cited by 250 publications

(155 citation statements)

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“…Since most finiteelement models ignore the periodontal ligament (Gupta et al, 1973;Knoell, 1977;Hart and Thongpreda, 1988;Hart et al, 1992;Strait et al, 2003), this question is not easily addressed with reference to single models. We thus investigated the possibility that in the absence of occlusal loads, the teeth contribute insignificantly to structural stiffness and strength of the mandible.…”

Section: Finite-element Analysismentioning

confidence: 99%

“…Hart and Thongpreda (1988) and Hart et al (1992) defined three main mandibular regions: the left mandible, symphysis, and right mandible. Similar mandibular regions were defined by Korioth et al (1992): the symphysis, gonion region, and the rest of the mandible.…”

Section: Finite-element Analysismentioning

confidence: 99%

“…The use of computed tomography (CT) scans to develop a three-dimensional geometric model was pioneered by Hart and Thongpreda (1988). Hart et al (1992) offered further refinements of better geometry, mesh density, and realistic material properties assignment. The work of Korioth et al (1992) represents the first attempt to include the periodontal ligament and dental structures in combination with cortical and cancellous bone in a whole mandible model.…”

mentioning

confidence: 99%

“…The model obtained in this latter (indirect) way is in fact an idealized model, an approximation of the real object. Reconstruction from CT scans usually generates an improved virtual model because simplifying assumptions of geometry are avoided (Fü tterling et al, 1998;Hart and Thongpreda, 1988;Keyak et al, 1990;Hart et al, 1992;Korioth et al, 1992;Hollister et al, 1994;van Rietbergen et al, 1995;Lengsfeld et al, 1998;Vollmer et al, 2000). Obtaining geometry by CT is the preferred method since it offers more accuracy than reconstructions based on planar radiographs.…”

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Finite‐element modeling of the anthropoid mandible: The effects of altered boundary conditions

2005

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Finite-element modeling provides a full-field method for describing the stress environment of the skull. The utility of finite-element models, however, remains uncertain given our ignorance of whether such models validly portray states of stress and strain. For example, the effects of boundary conditions that are chosen to represent the mechanical environment in vivo are largely unknown. We conducted an in vitro strain gauge experiment on a fresh, fully dentate adult mandible of Macaca fascicularis to model a simplified loading regime by finite-element analysis for purposes of model validation. Under various conditions of material and structural complexity, we constructed dentate and edentulous models to measure the effects of changing boundary conditions (force orientation and nodal constraints) on strain values predicted at the gauge location. Our results offer a prospective assessment of the difficulties encountered when attempting to validate finite-element models from in vivo strain data. Small errors in the direction of load application produce significant changes in predicted strains. An isotropic model, although convenient, shows poor agreement with experimental strains, while a heterogeneous orthotropic model predicts strains that are more congruent with these data. Most significantly, we find that an edentulous model performs better than a dentate one in recreating the experimental strains. While this result is undoubtedly tied to our failure to model the periodontal ligament, we interpret the finding to mean that in the absence of occlusal loads, teeth within alveoli do not contribute significantly to the structural stiffness of the mandible. © 2005 Wiley-Liss, Inc. Key words: mandible; computed tomography; image reconstruction; finite-element methodFinite-element analysis (FEA) is the method of choice for theoretical analysis of the mechanical behavior of complex shapes in biology. The approach of FEA approximates real geometry using a large number of smaller simple geometric elements (e.g., triangles, bricks, tetrahedrons). Since complex shapes defy simple mathematical solution (i.e., in terms of engineering formulas), FEA simplifies a problem by analyzing multiple simple elements of known shapes with established mathematical solutions. These multiple solutions are in the end combined together to depict states of stress and strain through the entire structure.The last half of the 20th century saw increasing interest in testing and analysis of bone biomechanics (Cowin, 2001), including increased use of finite-element (FE) methods. Many theoretical and experimental studies have sought to quantify the distribution of stresses and strain in the mandible (Knoell, 1977;Hylander, 1984;Bouvier

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Section: Finite-element Analysismentioning

confidence: 99%

Section: Finite-element Analysismentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Finite‐element modeling of the anthropoid mandible: The effects of altered boundary conditions

2005

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] In general, most of these models have been severely compromised by the oversimplification of material properties, methods of verification, boundary conditions, and/or mandibular geometry. These problems will be addressed in the following sections.…”

Section: Finite Element Modelingmentioning

confidence: 99%

Development of a three‐dimensional finite element model of a human mandible containing endosseous dental implants. II. Variables affecting the predictive behavior of a finite element model of a human mandible

Al-Sukhun

Lindqvist

Helenius

2006

J Biomedical Materials Res

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The purpose of this study was to propose a systematic approach to validate a finite element model (FEM) of the human mandible and to investigate the effects of changing the geometry and orthotropic material properties on the FEM predictions. Thirty-eight variables affecting the material properties, boundary conditions, and the geometry of a FEM of a human mandible, including two dental implants, were systematically changed, creating a number of FEMs of the mandible. The effects of the variations were quantified as differences in the principal strain magnitudes modeled by the original FEM (gold standard), prior to the sensitivity analyses, and those generated by the changed FEMs. The material properties that had the biggest impact on the predicted cortical principal strain were the shear moduli (up to 31% in difference from the unchanged state), and the absence of cancellous bone (up to 34%). Alterations to the geometry of the mandibular cross section, such as an increase in corpus dimensions, had the greatest effect on principal strain magnitudes (up to 16%). Changes in the cortical thickness in relation to the width of the corpus section modified strain more than alterations to the corpus depth (14% and 5%, respectively). The relatively small difference (up to 13.5%) between the predicted and measured interimplant distances indicates the accuracy of the FEM. Changes in geometry and orthotropic material properties could induce significant changes in strain patterns. These values must therefore be chosen with care when using finite element techniques for predicting stresses, strains, and displacements.

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Biomechanics of torsion in the human mandible

Daegling¹,

Hylander²

1998

Am. J. Phys. Anthropol.

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Comparative investigations of mandibular function among primates have relied upon elementary structural models to estimate states of masticatory stress and strain. In these studies, mandibular corpus morphology is idealized as a homogeneous, isotropic symmetrical body of invariant geometry, and this morphological abstraction is used to infer relative levels of stress and strain in the jaw. In reality, none of the limiting conditions assumed by these models is satisfied; consequently, it is prudent to ask whether this "textbook" engineering approach is valid for the inference of biomechanical behavior. In this study, the predictions of various geometric representations of the mandibular corpus are evaluated against strains recorded in a sample of human jaws loaded in torsion. Symmetrical geometrical models (including various "robusticity" shape indices), although convenient, are probably not consistently reliable for predicting the distribution of strains in the corpus. The experimental data suggest that variations in cortical thickness within sections play a significant role in determining the profile of relative strains. For comparative applications, characterization of the corpus as an asymmetrical hollow ellipse (i.e., with differing thickness of medial and lateral cortical plates) may provide a reasonable portrayal of relative strains.

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Modeling the biomechanics of the mandible: A three-dimensional finite element study

Cited by 250 publications

References 11 publications

Finite‐element modeling of the anthropoid mandible: The effects of altered boundary conditions

Finite‐element modeling of the anthropoid mandible: The effects of altered boundary conditions

Development of a three‐dimensional finite element model of a human mandible containing endosseous dental implants. II. Variables affecting the predictive behavior of a finite element model of a human mandible

Biomechanics of torsion in the human mandible

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