Determination of the Elasticity Parameters of the Human Periodontal Ligament and the Location of the Center of Resistance of Single-rooted Teeth

Abstract

The elasticity parameters were found to be on a similar scale to those determined in previous studies on multi-rooted pig teeth.

Factors controlling anterior torque during C-implant-dependent en-masse retraction without posterior appliances

“…In the finite element model, teeth, alveolar bones, brackets, periodontal spaces, C-implant, and archwire were constructed with fine tetrahedron solid elements; the tooth and bracket were connected without interference, and each tooth contacted the next at the contact point as individual elements (Fig 2, D). In this study, teeth, alveolar bones, and periodontal spaces were assumed to be isoparametric and homogeneous linear elastic bodies, and the material properties of the elements were Young's modulus and Poisson's ratio according to the studies of Tanne et al, 28 Ziegler et al, 29 and Poppe et al 30 (Table I). In the system studies, we construct the x-axis as the in-out direction, the y-axis as the labiolingual direction, and the z-axis as the upper-lower direction, and defined 1x as the left central incisor direction, 1y as the labial direction, 1z as the apical direction, and the x-y plane as the occlusal plane of the teeth (Fig 3, A and B).…”

Bilinear elastic property of the periodontal ligament for simulation using a finite element mandible model

“…The modulus of elasticity (E) and Poisson's ratio (µ) of each tissue were referred from previous studies 7,[12][13][14][15][16] and are shown in Table 1. Nine combination groups of different bilinear elastic moduli of the PDL for each phase (E1 and E2) were assumed for comparison (M1-M9, Table 2).…”

“…Nine combination groups of different bilinear elastic moduli of the PDL for each phase (E1 and E2) were assumed for comparison (M1-M9, Table 2). Values of E1 and E2 which were to be investigated were proposed on the basis of earlier papers 7,8,12,13) . In these papers E1 and E2 ranged from 0.05 MPa to 0.…”

“…Table 1 The modulus of elasticity (E) and Poisson's ratio (µ) of the tooth structures and the bone. Data were referred from previous studies 7,[10][11][12][13][14] . Table 2 Nine combination groups of different elastic moduli of the PDL for the first and second phases (E1 and E2) with strain ranges below and over ε12=0.075, respectively.…”

“…However, because non-linear analysis requires a large number of load steps compared with linear structural analysis, the non-linear solutions in a tooth model usually result in a tremendous computer running time. To overcome the disadvantages of both linear and non-linear analyses, an alternative methodology using 2 moduli for approximation of the non-linear curve was advocated 7) . Measurements of the load-displacement relationship of teeth in rats 4) and pigs 8) were approximated by bilinear models.…”