scholarly journals A multi-patient analysis of the center of rotation trajectories using finite element models of the human mandible

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259794
Author(s):  
Torkan Gholamalizadeh ◽  
Sune Darkner ◽  
Peter Lempel Søndergaard ◽  
Kenny Erleben
Keyword(s):  
Finite Element ◽  
Tooth Movement ◽  
Single Point ◽  
Constant Load ◽  
Force System ◽  
Center Of Rotation ◽  
Principal Axes ◽  
Force Systems ◽  
Position Correction ◽  
Couple Pair

Studying different types of tooth movements can help us to better understand the force systems used for tooth position correction in orthodontic treatments. This study considers a more realistic force system in tooth movement modeling across different patients and investigates the effect of the couple force direction on the position of the center of rotation (CRot). The finite-element (FE) models of human mandibles from three patients are used to investigate the position of the CRots for different patients’ teeth in 3D space. The CRot is considered a single point in a 3D coordinate system and is obtained by choosing the closest point on the axis of rotation to the center of resistance (CRes). A force system, consisting of a constant load and a couple (pair of forces), is applied to each tooth, and the corresponding CRot trajectories are examined across different patients. To perform a consistent inter-patient analysis, different patients’ teeth are registered to the corresponding reference teeth using an affine transformation. The selected directions and applied points of force on the reference teeth are then transformed into the registered teeth domains. The effect of the direction of the couple on the location of the CRot is also studied by rotating the couples about the three principal axes of a patient’s premolar. Our results indicate that similar patterns can be obtained for the CRot positions of different patients and teeth if the same load conditions are used. Moreover, equally rotating the direction of the couple about the three principal axes results in different patterns for the CRot positions, especially in labiolingual direction. The CRot trajectories follow similar patterns in the corresponding teeth, but any changes in the direction of the force and couple cause misalignment of the CRot trajectories, seen as rotations about the long axis of the tooth.

scholarly journals An Analysis of the Stress Induced in the Periodontal Ligament during Extrusion and Rotation Movements: A Finite Element Method Linear Study Part I

2015 ◽  
Vol 16 (9) ◽  
pp. 740-743 ◽  
Author(s):  
HP Raghuveer ◽  
M Hemanth ◽  
MS Rani ◽  
Chathura Hegde ◽  
B Vedavathi ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Compressive Stress ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Root Resorption ◽  
Orthodontic Tooth Movement ◽  
3D Fem ◽  
Force System ◽  
Element Method

ABSTRACT Background Orthodontic tooth movement occurs due to various biomechanical changes in the periodontium. Forces within the optimal range yield maximum tooth movement with minimum deleterious effects. Among various types of tooth movements, extrusion and rotational movements are seen to be associated with the least amount of root resorption and have not been studied in detail. Therefore in this study, the stress patterns in the periodontal ligament (PDL) were evaluated with extrusion and rotational movements using the finite element method FEM. Materials and methods A three-dimensional (3D) FEM model of the maxillary incisors was generated using SOLIDWORKS modeling software. Stresses in the PDL were evaluated with extrusive and rotational movements by a 3D FEM using ANSYS software with linear material properties. Results It was observed that with the application of extrusive load, the tensile stresses were seen at the apex, whereas the compressive stress was distributed at the cervical margin. With the application of rotational movements, maximum compressive stress was distributed at the apex and cervical third, whereas the tensile stress was distributed on cervical third of the PDL on the lingual surface. Conclusion For extrusive movements, stress values over the periodontal ligament was within the range of optimal stress value as proposed by Lee, with a given force system by Profitt as optimum forces for orthodontic tooth movement using linear properties. During rotation there are stresses concentrated at the apex, hence due to the concentration of the compressive forces at the apex a clinician must avoid placing heavy stresses during tooth movement. How to cite this article Hemanth M, Raghuveer HP, Rani MS, Hegde C, Kabbur KJ, Vedavathi B, Chaithra D. An Analysis of the Stress Induced in the Periodontal Ligament during Extrusion and Rotation Movements: A Finite Element Method Linear Study Part I. J Contemp Dent Pract 2015;16(9):740-743.

Finite Element Calculation of Bone Remodeling in Orthodontics by Using Forces and Moments

2003 ◽  
Vol 03 (02) ◽  
pp. 123-134 ◽  
Author(s):  
Martin Geiger ◽  
Juergen Schneider ◽  
Franz G. Sander
Keyword(s):  
Finite Element ◽  
Bone Remodeling ◽  
Tooth Movement ◽  
Orthodontic Appliances ◽  
Force System ◽  
Canine Retraction ◽  
Single Tooth ◽  
Linear Material ◽  
Orthodontic Devices

Orthodontic appliances induce bone remodeling by acting as systems of forces and moments onto the crown of a tooth. These forces and moments should be within low physiological range to avoid resorptions. This is often realized by the use of superelastic wires or springs. For improving the design of these devices, we use the Finite Element Method (FEM) to simulate the behavior of teeth and devices. Great advantages were made in simulating the bone remodeling during the movement of a single tooth. Due to the lack of element types implementing hysteresis in the stress/strain graph, it is difficult to simulate the non-linear material properties of the superelastic wires made of NiTi-alloys. For this reason, we integrated the measurement of the devices into the calculation of the tooth movement. In this study we simulate the orthodontic long-term tooth movement of the canine retraction, using the new hybrid retraction spring.5 This spring allows a well-defined adjustment of the acting force system. The result of this study provides an example of how this approach can be used for future comparison of different orthodontic devices.

scholarly journals Efficient Design of a Clear Aligner Attachment to Induce Bodily Tooth Movement in Orthodontic Treatment Using Finite Element Analysis

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4926
Author(s):  
Kyungjae Hong ◽  
Wonhyeon Kim ◽  
Emmanuel Eghan-Acquah ◽  
Jongho Lee ◽  
Bukyu Lee ◽  
...  
Keyword(s):  
Finite Element ◽  
Orthodontic Treatment ◽  
Tooth Movement ◽  
Axial Rotation ◽  
Tooth Surface ◽  
Central Incisor ◽  
Efficient Design ◽  
Element Analysis ◽  
Force Systems ◽  
Clear Aligner

Clear aligner technology has become the preferred choice of orthodontic treatment for malocclusions for most adult patients due to their esthetic appeal and comfortability. However, limitations exist for aligner technology, such as corrections involving complex force systems. Composite attachments on the tooth surface are intended to enable active control of tooth movements. However, unintended tooth movements still occur. In this study, we present an effective attachment design of an attachment that can efficiently induce tooth movement by comparing and analyzing the movement and rotation of teeth between a general attachment and an overhanging attachment. The 3D finite element modes were constructed from CBCT data and used to analyze the distal displacement of the central incisor using 0.5- and 0.75-mm-thick aligners without an attachment, and with general and overhanging attachments. The results show that the aligner with the overhanging attachment can effectively reduce crown tipping and prevent axial rotation for an intended distal displacement of the central incisor. In all models, an aligner with or without attachments was not capable of preventing the lingual inclination of the tooth.

scholarly journals Initial force systems during bodily tooth movement with plastic aligners and composite attachments: A three-dimensional finite element analysis

2014 ◽  
Vol 85 (3) ◽  
pp. 454-460 ◽  
Author(s):  
Juan Pablo Gomez ◽  
Fabio Marcelo Peña ◽  
Valentina Martínez ◽  
Diana C. Giraldo ◽  
Carlos Iván Cardona
Keyword(s):  
Finite Element ◽  
Tooth Movement ◽  
Three Dimensional ◽  
Root Surface ◽  
Fe Model ◽  
Force System ◽  
Bodily Movement ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Initial Force

ABSTRACT Objective:  To describe, using a three-dimensional finite element (FE) model, the initial force system generated during bodily movement of upper canines with plastic aligners with and without composite attachments. Materials and Methods:  A CAD model of an upper right canine, its alveolar bone and periodontal ligament, thermoformed plastic aligner, and two light-cured composite attachments were constructed. A FE model was used to analyze the effects of imposing a distal movement condition of 0.15 mm on the aligner (simulating the mechanics used to produce a distal bodily movement) with and without composite attachments. Results:  In terms of tension and compression stress distribution, without composite attachments a compression area in the cervical third of the distal root surface and a tension area in the apical third of the mesial surface were observed. With composite attachments, uniform compression areas in the distal root surface and uniform tension area in the mesial root surface were observed. Compression areas in the active surfaces of the composite attachments were also observed. In terms of movement patterns, an uncontrolled distal inclination, with rotation axis between the middle and cervical root thirds, was observed without composite attachment. Distal bodily movement (translation) was observed with composite attachment. Conclusions: In a three-dimensional FE analysis of a plastic aligner system biomechanically supplementary composite attachments generate the force system required to produce bodily tooth movement; the absence of biomechanically supplementary composite attachments favors the undesired inclination of the tooth during the translation movements.

scholarly journals Three-dimensional nonlinear prediction of tooth movement from the force system and root morphology

2020 ◽  
Vol 90 (6) ◽  
pp. 811-822
Author(s):  
Roberto Savignano ◽  
Rodrigo F. Viecilli ◽  
Udochukwu Oyoyo
Keyword(s):  
Tooth Movement ◽  
Three Dimensional ◽  
Cone Beam ◽  
Nonlinear Prediction ◽  
Element Analysis ◽  
Force System ◽  
Force Ratio ◽  
Force Direction ◽  
Force Systems ◽  
The Moment

ABSTRACT Objectives To determine the different impact of moment-to-force ratio (M:F) variation for each tooth and spatial plane and to develop a mathematical model to predict the orthodontic movement for every tooth. Materials and Methods Two full sets of teeth were obtained combining cone-beam computed tomography (CBCT) and optical scans for two patients. Subsequently, a finite element analysis was performed for 510 different force systems for each tooth to evaluate the centers of rotation. Results The center of CROT locations were analyzed, showing that the M:F effect was related to the spatial plane on which the moment was applied, to the force direction, and to the tooth morphology. The tooth dimensions on each plane were mathematically used to derive their influence on the tooth movement. Conclusion This study established the basis for an orthodontist to determine how the teeth move and their axes of resistance, depending on their morphology alone. The movement is controlled by a parameter (k), which depends on tooth dimensions and force system features. The k for a tooth can be calculated using a CBCT and a specific set of covariates.

scholarly journals Comparative Analysis of Stress in the Periodontal Ligament and Center of Rotation in the Tooth after Orthodontic Treatment Depending on Clear Aligner Thickness—Finite Element Analysis Study

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 324
Author(s):  
Jeong-Hee Seo ◽  
Emmanuel Eghan-Acquah ◽  
Min-Seok Kim ◽  
Jeong-Hyeon Lee ◽  
Yong-Hoon Jeong ◽  
...  
Keyword(s):  
Finite Element ◽  
Periodontal Ligament ◽  
Orthodontic Treatment ◽  
Tooth Movement ◽  
Axial Rotation ◽  
Finite Element Models ◽  
Clinical Effects ◽  
Principal Stresses ◽  
Element Analysis ◽  
Center Of Rotation

Lately, in orthodontic treatments, the use of transparent aligners for the correction of malocclusions has become prominent owing to their intrinsic advantages such as esthetics, comfort, and minimal maintenance. Attempts at improving upon this technology by varying various parameters to investigate the effects on treatments have been carried out by several researchers. Here, we aimed to investigate the biomechanical and clinical effects of aligner thickness on stress distributions in the periodontal ligament and changes in the tooth’s center of rotation. Dental finite element models comprising the cortical and cancellous bones, gingiva, teeth, and nonlinear viscoelastic periodontal ligaments were constructed, validated, and used together with aligner finite element models of different aligner thicknesses to achieve the goal of this study. The finite element analyses were conducted to simulate the actual orthodontic aligner treatment process for the correction of malocclusions by generating pre-stresses in the aligner and allowing the aligner stresses to relax to induce tooth movement. The results of the analyses showed that orthodontic treatment in lingual inclination and axial rotation with a 0.75 mm-thick aligner resulted in 6% and 0.03% higher principal stresses in the periodontal ligament than the same treatment using a 0.05 mm-thick aligner, respectively. Again, for both aligner thicknesses, the tooth’s center of rotation moved lingually and towards the root direction in lingual inclination, and diagonally from the long axis of the tooth in axial rotation. Taken together, orthodontic treatment for simple malocclusions using transparent aligners of different thicknesses will produce a similar effect on the principal stresses in the periodontal ligament and similar changes in the tooth’s center of rotation, as well as sufficient tooth movement. These findings provide orthodontists and researchers clinical and biomechanical evidence about the effect of transparent aligner thickness selection and its effect on orthodontic treatment.

Design of flexure revolute joint based on compliance and stiffness ellipsoids

2021 ◽  
pp. 095441002110169
Author(s):  
Jing Zhang ◽  
Hong-wei Guo ◽  
Juan Wu ◽  
Zi-ming Kou ◽  
Anders Eriksson
Keyword(s):  
Finite Element ◽  
Single Point ◽  
Synthesis Method ◽  
Nonlinear Finite Element ◽  
Finite Element Analyses ◽  
Rotational Stiffness ◽  
Rotational Angle ◽  
Parameterized Model ◽  
Flexure Joints ◽  
Translational Stiffness

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized model of the flexible unit was established to achieve a reasonable allocation of flexibility in different directions. Based on the single-parameter error analysis, two error models were established to evaluate the designed flexure joint. The rotational stiffness, the translational stiffness, and the maximum rotational angle of the joints were analyzed by nonlinear finite element analyses. The rotational angle of one joint can reach 25.5° in one direction. The rotational angle of the series FR joint can achieve 50° in one direction. Experiments on single and series flexure joints were carried out to verify the correctness of the design and analysis of the flexure joint.

scholarly journals Dual-section versus conventional archwire for en-masse retraction of anterior teeth with direct skeletal anchorage: a finite element analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ryo Hamanaka ◽  
Daniele Cantarella ◽  
Luca Lombardo ◽  
Lorena Karanxha ◽  
Massimo Del Fabbro ◽  
...  
Keyword(s):  
Finite Element ◽  
Tooth Movement ◽  
Occlusal Plane ◽  
Skeletal Anchorage ◽  
Element Analysis ◽  
Posterior Teeth ◽  
Posterior Portion ◽  
Anterior Teeth ◽  
Retraction Force ◽  
En Masse Retraction

Abstract Background The aim of this study is to compare the biomechanical effects of the conventional 0.019 × 0.025-in stainless steel archwire with the dual-section archwire when en-masse retraction is performed with sliding mechanics and skeletal anchorage. Methods Models of maxillary dentition equipped with the 0.019 × 0.025-in archwire and the dual-section archwire, whose anterior portion is 0.021 × 0.025-in and posterior portion is 0.018 × 0.025-in were constructed. Then, long-term tooth movement during en-masse retraction was simulated using the finite element method. Power arms of 8, 10, 12 and 14 mm length were employed to control anterior torque, and retraction forces of 2 N were applied with a direct skeletal anchorage. Results For achieving bodily movement of the incisors, power arms longer than 14 mm were required for the 0.019 × 0.025-in archwire, while between 8 and 10 mm for the dual-section archwire. The longer the power arms, the greater the counter-clockwise rotation of the occlusal plane was produced. Frictional resistance generated between the archwire and brackets and tubes on the posterior teeth was smaller than 5% of the retraction force of 2 N. Conclusions The use of dual-section archwire might bring some biomechanical advantages as it allows to apply retraction force at a considerable lower height, and with a reduced occlusal plane rotation, compared to the conventional archwire. Clinical studies are needed to confirm the present results.

scholarly journals Tooth Movement Efficacy of Retraction Spring Made of a New Low Elastic Modulus Material, Gum Metal, Evaluated by the Finite Element Method

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2934
Author(s):  
Naohiko Tamaya ◽  
Jun Kawamura ◽  
Yoshinobu Yanagi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Tooth Movement ◽  
The Finite Element Method ◽  
Bodily Movement ◽  
Anterior Teeth ◽  
Low Elastic Modulus ◽  
Space Closure ◽  
Gum Metal ◽  
Element Method

The aim of this study was to evaluate the tooth movement efficacy of retraction springs made of a new β-titanium alloy, “gum metal”, which has a low Young’s modulus and nonlinear super elasticity. Using double loop springs incorporated into an archwire made of gum metal (GUM) and titanium molybdenum alloy (TMA), the maxillary anterior teeth were moved distally to close an extraction space. The long-term movements were simulated by the finite element method. Its procedure was constructed of two steps, with the first step being the calculation of the initial tooth movement produced by elastic deformation of the periodontal ligament, and in the second step, the alveolar socket was moved by the initial tooth movement. By repeating these steps, the tooth moved by accumulating the initial tooth movement. The number of repeating calculations was equivalent to an elapsed time. In the GUM and TMA springs, the anterior teeth firstly tipped lingually, and then became upright. As a result of these movements, the canine could move bodily. The amount of space closure in GUM spring was 1.5 times that in TMA spring. The initial tipping angle of the canine in the GUM spring was larger than that in the TMA spring. The number of repeating calculations required for the bodily movement in the GUM spring was about two times that in the TMA spring. It was predicted that the speed of space closure in the GUM spring was smaller than that in the TMA spring.

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