scholarly journals Finite element study of controlling factors of anterior intrusion and torque during Temporary Skeletal Anchorage Device (TSAD) dependent en masse retraction without posterior appliances: Biocreative hybrid retractor (CH-retractor)

2019 ◽  
Vol 90 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Sung-Seo Mo ◽  
Min-Ki Noh ◽  
Seong-Hun Kim ◽  
Kyu-Rhim Chung ◽  
Gerald Nelson
Keyword(s):  
Finite Element ◽  
Anterior Segment ◽  
Two Dimensions ◽  
Element Analysis ◽  
Bodily Movement ◽  
Anterior Teeth ◽  
Temporary Skeletal Anchorage ◽  
Anterior Segments ◽  
Sophisticated Analysis ◽  
En Masse Retraction

ABSTRACT Objectives: To evaluate, using the finite element method (FEM), the factors that allow control of the anterior teeth during en masse retraction with the Biocreative hybrid retractor (CH-retractor) using different sizes of nickel-titanium (NiTi) archwires and various gable bends on the stainless-steel (SS) archwires. Materials and Methods: Using FEM, the anterior archwire section, engaged on the anterior dentition, was modeled in NiTi, and another assembly, the posterior guiding archwire, was modeled in SS. Two dimensions (0.016 × 0.022- and 0.017 × 0.025-inch NiTi) of the anterior archwires and different degrees (0°, 15°, 30°, 45°, and 60°) of the gable bends on the guiding wire were applied to the CH-retractor on the anterior segment to evaluate torque and intrusion with 100-g retraction force to TSADs. Finite element analysis permitted sophisticated analysis of anterior tooth displacement. Results: With a 0° gable bend all anterior teeth experienced extrusion. The canines showed a larger amount of extrusion than did the central and lateral incisors. With a gable bend of >15°, all anterior teeth exhibited intrusion. Bodily movement of the central incisor required a 30°∼45° gable bend when using anterior segments of 0.016 × 0.022-inch NiTi and 15°∼30° gable bend with the 0.017 × 0.025-inch NiTi. Conclusions: With the CH-retractor, varying the size of the NiTi archwire and/or varying the amount of gable bend on the SS archwire affects control of the anterior teeth during en masse retraction without a posterior appliance.

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 Characteristics and Dynamics of Full Arch Distalization Using Transpalatal Arches with Midpalatal and Interradicular Miniscrews as Temporary Anchorage Devices: A Preliminary Finite Element Analysis

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Mashallah Khanehmasjedi ◽  
Sepideh Bagheri ◽  
Vahid Rakhshan ◽  
Mojtaba Hasani
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Orthodontic Appliances ◽  
Element Analysis ◽  
Midpalatal Suture ◽  
Second Molar ◽  
Bodily Movement ◽  
Anterior Teeth ◽  
The Right

Introduction. Miniscrews have proved quite effective in fixed orthodontic treatment. They can be placed in areas like palatal interradicular zones or midpalatal suture. Despite the value of these methods and their ever-increasing use, their characteristics are not assessed before when implanted in palatal interradicular areas or in the midpalatal suture. We aimed to assess, for the first time, the dynamics of full arch distalization using such miniscrews. Methods. A 3D model of maxilla with all permanent dentition was created from a CT scan volume. Tissues were segmented and differentiated. Afterward, miniscrews and appliances were designed, and the whole model was registered within a finite element analysis software by assigning proper mechanical properties to tissues and orthodontic appliances. The full arches were distalized using transpalatal arches with miniscrews as anchorage devices (in two different models). The extents of stresses and patterns of movements of various elements (teeth, miniscrews, appliances, tissues) were estimated. Results and Conclusions. Comparing the two models, it is obvious that in both models, the stress distribution is the highest in the TPA arms and the head of the miniscrew where the spring is connected. In comparison with the displacement in the X-axis, the “mesial in” rotation is seen in the first molar of both models. But there is one exception and that is the “mesial out” rotation of the right second molar. In all measurements, the amount of movement in Model 2 (with palatal interradicular miniscrews) is more than that in Model 1 (with midpalatal miniscrew). In the Y-axis, more tipping is seen in Model 2, especially the anterior teeth (detorque) and the first molar, but in Model 1, bodily movement of the first molar is more evident. Along the Z-axis, the mesial intrusion of the first molar and the distal extrusion of this tooth can be seen in both models. Again, the displacement values are higher in the second model (with interradicular miniscrews). In comparison with micromotion and stress distribution of miniscrews, in Model 1, maximum stress and micromotion is observed at the head of the miniscrew where it is attached to the spring. Of course, this amount of micromotion increases over time. The same is true for Model 2, but with a lower micromotion. As for the amount of stress, the stress distribution in both miniscrews of both models is almost uniform and rather severe.

The Effects of Mini Implant and Anterior Arch Hook Heights on En Masse Retraction: A Finite Element Analysis

2013 ◽  
Vol 461 ◽  
pp. 993-1001
Author(s):  
Wen Wen Deng ◽  
Fang Wang ◽  
Ferdinand M. Machibya ◽  
Shang Gao ◽  
Xiao Long Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Cone Beam Ct ◽  
Three Dimensional ◽  
Cone Beam ◽  
Finite Element Models ◽  
Treatment Results ◽  
Element Analysis ◽  
Anterior Teeth ◽  
Orofacial Region ◽  
En Masse Retraction

Introduction: An en-masse retraction with mini implant (MI) anchorage may be associated with unwanted intrusion/extrusion and uncontrolled tipping of anterior teeth. An optimum combination of MIs and hooks heights is required for proper treatment results. Materials and Methods: Maxillary finite element models were constructed from a cone beam CT scan of a patient’s orofacial region. The initial tooth displacement at 200g force with 0.019 × 0.025-in stainless steel working archwires engaged in 0.022 brackets slot was assessed. The three-dimensional displacement was examined at various MI and AAH heights. Results: The lower MI position caused extrusion of the central incisors, but the teeth were intruded at higher (6- and 8-mm) MI heights. While the shorter (2- and 4-mm) hooks extruded the central incisors, the higher (6- and 8-mm) intruded the teeth. The higher MI and hooks reduced the palatal tipping of central incisors. The distobucal cusp of the first molar was intruded, while the mesiobucal cusp was extruded in all models: Nonetheless, the shorter hooks and low MI had small molar tipping effects. Conclusions: The higher MIs caused intrusion and less palatal tipping of the central incisors crowns. The increase in hook height resulted into extrusion and reduction in palatal tipping of the central incisors crowns.

Three-Dimensional Finite Element Analysis on En-Masse Retraction of the Maxillary Anterior Teeth With Quantitative Combined Loading Control

2020 ◽  
Vol 46 (3) ◽  
pp. 214-220
Author(s):  
Hui Qie ◽  
Lingliang Kong ◽  
Fan Zhang ◽  
Chenxi Li ◽  
Lin Lu ◽  
...  
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Combined Loading ◽  
Element Analysis ◽  
Sliding Method ◽  
Anterior Teeth ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
En Masse Retraction

This study aims to elucidate the biomechanical effects of combined loading of maxillary anterior and posterior implants using the sliding method on en-masse retraction of the anterior teeth and to quantify the loading ratio (LR) of anterior and posterior implants to achieve controlled retraction of the maxillary anterior teeth. A three-dimensional finite element model of the maxilla-upper dentition appliance was constructed. Implants were placed on the distal (A) and mesial (B) sides of the lateral incisors as well as on the mesial (C) side of the first molar and different amounts of force were loaded between the implants using 2- or 5-mm traction hooks. The labiolingual movement of the anterior teeth was recorded and the relationship between the LR of the implants and the movement of the central incisors was evaluated. With 2-mm traction hooks, the central incisors exhibited a translation tendency during retraction at lower A/C and B/C LR and labial or lingual crown inclination at higher values. With 5-mm traction hooks, the central incisors, lateral incisors, and canine teeth exhibited a labial crown inclination. The results of this study suggest that 2-mm traction hooks can cause labial crown inclination, translation tendency during retraction, or lingual crown inclination of the central incisors due to alterations in the LR of the anterior and posterior implants. The central incisors only exhibited labial crown inclination during combined loading of the anterior and posterior implants when 5-mm traction hooks were used.

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.

scholarly journals Finite Element Analysis of Mandibular Anterior Teeth with Healthy, but Reduced Periodontium

2021 ◽  
Vol 11 (9) ◽  
pp. 3824
Author(s):  
Ioana-Andreea Sioustis ◽  
Mihai Axinte ◽  
Marius Prelipceanu ◽  
Alexandra Martu ◽  
Diana-Cristala Kappenberg-Nitescu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Real Data ◽  
Element Analysis ◽  
Anterior Teeth ◽  
Applied Forces ◽  
Orthodontic Forces

Finite element analysis studies have been of interest in the field of orthodontics and this is due to the ability to study the stress in the bone, periodontal ligament (PDL), teeth and the displacement in the bone by using this method. Our study aimed to present a method that determines the effect of applying orthodontic forces in bodily direction on a healthy and reduced periodontium and to demonstrate the utility of finite element analysis. Using the cone-beam computed tomography (CBCT) of a patient with a healthy and reduced periodontium, we modeled the geometric construction of the contour of the elements necessary for the study. Afterwards, we applied a force of 1 N and a force of 0.8 N in order to achieve bodily movement and to analyze the stress in the bone, in the periodontal ligament and the absolute displacement. The analysis of the applied forces showed that a minimal ligament thickness is correlated with the highest value of the maximum stress in the PDL and a decreased displacement. This confirms the results obtained in previous clinical practice, confirming the validity of the simulation. During orthodontic tooth movement, the morphology of the teeth and of the periodontium should be taken into account. The effect of orthodontic forces on a particular anatomy could be studied using FEA, a method that provides real data. This is necessary for proper treatment planning and its particularization depends on the patient’s particular situation.

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