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 ◽  
...  

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.

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 324
Author(s):  
Jeong-Hee Seo ◽  
Emmanuel Eghan-Acquah ◽  
Min-Seok Kim ◽  
Jeong-Hyeon Lee ◽  
Yong-Hoon Jeong ◽  
...  

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.


2010 ◽  
Vol 1 (3) ◽  
pp. 159-162 ◽  
Author(s):  
M Hemanth ◽  
Siddharth D Lodaya

ABSTRACT This study was designed to investigate the stress pattern and magnitude in periodontal ligament of maxillary central incisor for tipping and bodily tooth movement using finite element method and to determine the optimal orthodontic force required for bodily tooth movements compared to previous clinical, histologic, and laboratory studies. The three-dimensional FEM consisting of 27000 isoparametric elements of maxillary central incisor was constructed based on the average anatomic morphology given by Wheeler. Principal stresses in PDL were determined for tipping and bodily tooth movement. On application of optimal forces for tipping and bodily tooth movement, stress value seen in PDL was less, however the distribution of stress pattern coincided with the previous studies.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ryo Hamanaka ◽  
Daniele Cantarella ◽  
Luca Lombardo ◽  
Lorena Karanxha ◽  
Massimo Del Fabbro ◽  
...  

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.


2021 ◽  
Vol 11 (9) ◽  
pp. 3824
Author(s):  
Ioana-Andreea Sioustis ◽  
Mihai Axinte ◽  
Marius Prelipceanu ◽  
Alexandra Martu ◽  
Diana-Cristala Kappenberg-Nitescu ◽  
...  

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.


2020 ◽  
Vol 12 (11) ◽  
pp. 1249-1254
Author(s):  
Long Qin ◽  
Qiao Wang ◽  
Dongliang Zhang ◽  
Xin He ◽  
Binbin Wu

The different positions and angles of attachment affecting the buccolingual movement of the maxillary molars, especially lingual tipping and negative torque movements, were biomechanically analyzed in order to determine how to better control and prevent unwanted movement of clear aligners. The aligner can be designed and placed appropriately to improve expected tooth movement. Based on mechanical principles, the force system of attachment was analyzed, and the optimum attachment position and angle for tipping and negative torque movement was determined. Attachment close to the enamel-cementum junction (ECJ) was found to achieve the best F (M/L) during negative torque movement; however, the angle should also be adjusted. Attachment close to the occlusal surface achieved greater tipping force at specific angles. When more tipping movement is required, it is recommended to place the attachment 3–5 mm from the ECJ. The angle of the attachment should be 110–120 degrees from the tooth surface. When place the attachment 4–5 mm from the ECJ, the angle of the attachment should be between 145 and 146.5 degrees.


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