Optimized Attachment to Achieve Different Buccolingual Movement of Maxillary Molars in Clear Aligner Orthodontic System: Biomechanical Analysis

2020 ◽  
Vol 12 (11) ◽  
pp. 1249-1254
Author(s):  
Long Qin ◽  
Qiao Wang ◽  
Dongliang Zhang ◽  
Xin He ◽  
Binbin Wu
Keyword(s):  
Tooth Movement ◽  
Biomechanical Analysis ◽  
Occlusal Surface ◽  
Tooth Surface ◽  
Force System ◽  
Maxillary Molars ◽  
Clear Aligner

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.

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 Expression of Nitric Oxide Synthases in Orthodontic Tooth Movement

2009 ◽  
Vol 79 (3) ◽  
pp. 502-508 ◽  
Author(s):  
Dorrin Nilforoushan ◽  
Morris Frank Manolson
Keyword(s):  
Tooth Movement ◽  
Expression Patterns ◽  
Orthodontic Tooth Movement ◽  
Pressure Side ◽  
Free Zone ◽  
Maxillary Molars ◽  
Pdl Cells ◽  
No Signaling ◽  
Nos Isoforms ◽  
Nnos Expression

Abstract Objective: To investigate differential expression of NOS isoforms in periodontal ligament (PDL) and bone in tension and pressure sides using a rat model of orthodontic tooth movement (OTM). Materials and Methods: Immunohistochemistry with NOS isoform (iNOS, eNOS, and nNOS) antibodies was performed on horizontal sections of the first maxillary molars subjected to 3 and 24 hours of OTM. The PDL and adjacent osteocytes of the distopalatal root at pressure and tension areas were analyzed for expression of these proteins. The contralateral molar served as a control. Results were analyzed with one-way ANOVA and with two-way ANOVA. Results: Expression of all isoforms was increased in the tension side. iNOS and nNOS expression in the pressure side with cell-free zone was decreased but in the pressure side without cell-free zone was increased. The number of eNOS-positive cells did not change, but the intensity of the staining was visibly increased in the tension side. Duration of OTM changed only the pattern of nNOS expression. Osteocyte NOS expression did not change significantly in response to OTM. Conclusions: All NOS isoforms are involved in OTM with different expression patterns between tension and pressure sides, with nNOS being more involved in early OTM events. NOS expression did not change in osteocytes, suggesting that PDL cells rather than osteocytes are the mechanosensors in early OTM events with regard to NO signaling.

scholarly journals Molar Uprighting: A Considerable and Safe Decision to Avoid Prosthetic Treatment

2017 ◽  
Vol 11 (1) ◽  
pp. 466-475 ◽  
Author(s):  
Taísa Boamorte Raveli ◽  
Dirceu Barnabé Raveli ◽  
Kelei Cristina de Mathias Almeida ◽  
Ary dos Santos Pinto
Keyword(s):  
Orthodontic Treatment ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Female Adult ◽  
Bone Apposition ◽  
Force System ◽  
Second Molar ◽  
Space Closure ◽  
Practical Implications ◽  
Lower Molar

Background: Tipped lower molar over edentulous space is very common in orthodontics practice when adults seek treatment. The segmented arch technique features a predictable force system that provides a controlled release of force that can produce light and continuous tooth movement. Case Description: A female adult patient, who lost a permanent lower first molar, needed correction of the position of her permanent first molar place. Instead of making space for rehabilitation, it was closed after second molar uprighting and a balanced interdigitation was created without prosthetics. The patient was successfully treated with segmented arch technique using root correction spring activated with geometry VI to promote uprighting of a tipped molar and Niti spring coil to promote space closure. Practical Implications: Segmented arch technique is known to provide predictable light and continuous forces, which is very much indicated in adult treatment. There are several things to consider when orthodontically treating adult patients. Their periodontal conditions might not be ideal, less bone apposition may occur, and side effects of orthodontic tooth movement are expected. Thus, a predictable and controlled orthodontic treatment is needed.

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.

Three-Dimensional Digitalized Surface and Volumetric Analysis of Posterior Prefabricated Zirconia Crowns for Children

2019 ◽  
Vol 43 (4) ◽  
pp. 231-238 ◽  
Author(s):  
Hyeonjong Lee ◽  
Yong Kwon Chae ◽  
Hyo-Seol Lee ◽  
Sung Chul Choi ◽  
Ok Hyung Nam
Keyword(s):  
Stainless Steel ◽  
Three Dimensional ◽  
Volumetric Analysis ◽  
Occlusal Surface ◽  
Tooth Surface ◽  
Zirconia Crowns ◽  
Tooth Preparation ◽  
3D Software ◽  
Surface Morphologies ◽  
Axial Surface

Objectives: This study was designed to compare the surface morphologies and volumes of posterior prefabricated zirconia crowns and posterior stainless steel crowns (SSCs) using digitalized three-dimensional (3D) reconstructed images. Study design: We tested prefabricated zirconia crowns (NuSmile ZR; Orthodontic Technologies, Houston, TX, USA) and SSCs (Kids Crown; Shinhung, Seoul, Korea) used to restore left maxillary and mandibular molars. A Rainbow scanner (Dentium, Seoul, Korea) was used to digitise the inner and outer surface morphologies of all crowns. The data were superimposed and evaluated using 3D software. The differences between the outer and inner surfaces and inner volume were measured. Results: The differences between the two types of crowns differed by tooth surface. At the occlusal surface, the differences were greater at the cusp tip than the fossa. At the axial level, the differences decreased toward the gingival margins. Also, relative volumetric ratios varied. Conclusions: Tooth preparation prior to placement of prefabricated zirconia crowns requires special consideration. Greater amounts of tooth reduction are necessary for posterior zirconia crowns than for SSCs. The occlusal surface requires more tooth reduction than the axial surface and the gingival margin.

Morphological analysis of the occlusal surface of maxillary molars in Koreans

2016 ◽  
Vol 67 ◽  
pp. 15-21 ◽  
Author(s):  
Hong-Il Yoo ◽  
Dong-Wook Yang ◽  
Mi-Yeon Lee ◽  
Min-Seok Kim ◽  
Sun-Hun Kim
Keyword(s):  
Morphological Analysis ◽  
Occlusal Surface ◽  
Maxillary Molars

scholarly journals Localization of ODAM, PCNA, and CK14 in regenerating junctional epithelium during orthodontic tooth movement in rats

2013 ◽  
Vol 84 (3) ◽  
pp. 534-540 ◽  
Author(s):  
Seong-Suk Jue ◽  
Ji-Youn Kim ◽  
Seung-Hoon Na ◽  
Kyung-Dal Jeon ◽  
Hee-Joon Bang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Normal Function ◽  
Nuclear Antigen ◽  
Tooth Surface ◽  
Basal Cells ◽  
Junctional Epithelium ◽  
Cell Proliferation Activity ◽  
Proliferation Activity

ABSTRACT Objective: To identify the regenerating junctional epithelium (JE) during orthodontic tooth movement in rats. Materials and Methods: Closed-coil springs were used to create a 20 g mesial force to the maxillary first molars. On days 1, 3, 7, 10, and 14 after force application, histologic changes in JE were examined by immunohistochemistry using proliferating cell nuclear antigen (PCNA), odontogenic ameloblast-associated protein (ODAM), and cytokeratin 14 (CK14). Results: On day 1, JE was destroyed and lost attachment to the tooth surface. Cell division activity was rarely observed in JE, and ODAM localization was weakly detected in damaged JE. By day 3, regenerating JE had not fully recovered. High cell proliferation activity and CK14 expression started to appear in most basal cells of JE. ODAM expression was reduced and appeared in a small area. By day 7, JE had almost recovered. Cell proliferation activity was still observed in several basal cells of JE, and ODAM expression was detected among JE cells. CK14 was hardly observed in JE except in the basal cells. By days 10 and 14, regenerated JE appeared. ODAM, PCNA, and CK14 expression was similar to that of the control. Conclusions: Damaged JE might recover rapidly during orthodontic tooth movement because basal cells of the remaining JE, which show higher proliferation activity, are involved in JE regeneration. Reduced ODAM expression during proliferation of JE cells may increase again after JE regeneration is complete. Therefore, ODAM may be associated with the normal function of JE.

scholarly journals Clear aligner orthodontic therapy of rotated mandibular round-shaped teeth: A finite element study

2019 ◽  
Vol 90 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Andrea Cortona ◽  
Gabriele Rossini ◽  
Simone Parrini ◽  
Andrea Deregibus ◽  
Tommaso Castroflorio
Keyword(s):  
Finite Element ◽  
Tooth Movement ◽  
Dental Arch ◽  
Cad Model ◽  
Rotational Movement ◽  
Finite Element Software ◽  
Displacement Pattern ◽  
Attachment Model ◽  
Clear Aligner ◽  
Periodontal Ligaments

ABSTRACT Objective: To evaluate, using the finite element method, the orthodontic rotational movement of a lower second premolar obtained with clear aligners, analyzing different staging and attachment configurations. Materials and Methods: A CAD model including a complete lower dental arch (with element 4.5 mesially rotated 30°) and the corresponding periodontal ligaments, attachments, and aligner was designed and imported to finite element software. Starting from the CAD model, six projects were created to simulate the following therapeutic combinations for correcting element 4.5 position: (1) without attachments, (2) single attachment placed on the buccal surface of element 4.5, (3) three attachments placed on the buccal surfaces of teeth 4.4 to 4.6. For each project, both 1.2° and 3° of aligner activation were considered. Results: All the analyzed configurations revealed a clockwise rotation movement of element 4.5 on the horizontal plane. Models with attachments showed a greater tooth displacement pattern than models without attachments. Simulations with attachments and 3° of aligner activation exhibited the best performance concerning tooth movement but registered high stresses in the periodontal ligaments, far from the ideal stress levels able to produce tooth rotational movement. Conclusions: The model with a single attachment and 1.2° of aligner activation was the most efficient, followed by the three attachment model with the same degree of activation. Aligner activation should not exceed 1.2° to achieve better control of movement and reasonable stress in periodontal structures.

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.

Sign in / Sign up

Export Citation Format

Share Document