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Xiao T, Su JY, Lei J, Zhang X, Yu J, Nie XP, Ying QH, Hou JX, Guo J. Effectiveness of different intrusion modes of maxillary anterior teeth with mini-implants in clear aligner treatment: a three-dimensional finite element analysis. BMC Oral Health 2024; 24:758. [PMID: 38956625 PMCID: PMC11218253 DOI: 10.1186/s12903-024-04537-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 06/26/2024] [Indexed: 07/04/2024] Open
Abstract
BACKGROUND The intrusion of maxillary anterior teeth is often required and there are various intrusion modes with mini-implants in clear aligner treatment. The objective of this study was to evaluate the effectiveness of maxillary anterior teeth intrusion with different intrusion modes, aiming to provide references for precise and safe intrusion movements in clinical practice. METHODS Cone-beam computed tomography and intraoral optical scanning data of a patient were collected. Finite element models of the maxilla, maxillary dentition, periodontal ligaments (PDLs), clear aligner (CA), attachments, and mini-implants were established. Different intrusion modes of the maxillary anterior teeth were simulated by changing the mini-implant site (between central incisors, between central and lateral incisor, between lateral incisor and canine), loading site (between central incisors, on central incisor, between central and lateral incisor, between lateral incisor and canine), and loading mode (labial loading and labiolingual loading). Ten conditions were generated and intrusive forces of 100 g were applied totally. Then displacement tendency of the maxillary anterior teeth and CA, and stress of the PDLs were analyzed. RESULTS For the central incisor under condition L14 and for the canine under conditions L11, L13, L23, and L33, the intrusion amount was negative. Under other conditions, the intrusion amount was positive. The labiolingual angulation of maxillary anterior teeth exhibited positive changes under all conditions, with greater changes under linguoincisal loading. The mesiodistal angulation of canine exhibited positive changes under labial loading, while negative changes under linguoincisal loading except for condition L14. CONCLUSIONS The intrusion amount, labiolingual and mesiodistal angulations of the maxillary anterior teeth were affected by the mini-implant site, loading site, and loading mode. Labial and linguoincisal loading may have opposite effects on the intrusion amount of maxillary anterior teeth and the mesiodistal angulation of canine. The labiolingual angulation of the maxillary incisors would increase under all intrusion modes, with greater increases under linguoincisal loading.
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Affiliation(s)
- Tian Xiao
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Shandong University, No.44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Jing-Yuan Su
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Shandong University, No.44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Jie Lei
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Shandong University, No.44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Xin Zhang
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Shandong University, No.44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Jian Yu
- Department of Radiology, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Shandong University, No.44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Xiu-Ping Nie
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Shandong University, No.44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Qiao-Hui Ying
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Shandong University, No.44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Jun-Xiang Hou
- R&D center, Wuxi EA Medical Instruments Technologies Ltd, Wuxi, 214174, China
| | - Jie Guo
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Shandong University, No.44-1 Wenhua Road West, Jinan, Shandong, 250012, China.
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Ciklacandir S, Gokce Kara G, Isler Y. A biomechanical investigation of miniscrews placed on a mandible for temporary anchorage; a patient-specific finite element analysis. Comput Methods Biomech Biomed Engin 2024:1-10. [PMID: 38907647 DOI: 10.1080/10255842.2024.2365909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 06/04/2024] [Indexed: 06/24/2024]
Abstract
Miniscrews are temporary skeletal anchorage devices that are widely used in orthodontic treatment, and their success depends on the placement area, angle, technique, and screw dimensions. This study aimed to investigate the effects of miniscrew lengths, insertion angles, and force directions on a mandible model consisting of teeth, cortical and cancellous bones. One Dental Volumetric Tomography (DVT) scan from a patient who had miniscrews were used for mandibular bone modeling to perform finite element analysis. The model variables included miniscrew lengths (6, 8, and 10 mm), insertion angles (-15°, 45°, 60°, and 90°), and force directions (30°, 45°, and 60°). The minimum and maximum stresses were calculated as 18.61 and 37.11 MPa at 6 mm and 10 mm, respectively. According to the insertion angles, the lowest stress was observed at 60°, while the highest stress was found at 15° in the ventral direction. At force directions, the lowest stress was at 60°, and the highest stress was at 45°. However, there were no significant differences in insertion angles and force directions. A statistically significant difference was determined in miniscrew length. As a result, the best result was calculated to be 6 mm inserted at a 60° angle, which could induce the lowest stress. Increasing the miniscrew length will increase the stress on the mandible. In addition, because of the higher force direction, stress decreases with shorter power arms.
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Affiliation(s)
- Samet Ciklacandir
- Department of Biomedical Engineering, Izmir Katip Celebi University, Izmir, Turkey
| | - Gokcenur Gokce Kara
- Faculty of Dentistry, Department of Orthodontics, Marmara University, Istanbul, Turkey
| | - Yalcin Isler
- Department of Biomedical Engineering, Izmir Katip Celebi University, Izmir, Turkey
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Caragiuli M, Candelari M, Zalunardo F, Bruno G, De Stefani A, Brunzini A, Mandolini M. Effects of Oral Appliances for Obstructive Sleep Apnoea in Reduced Periodontium: A Finite Element Analysis. Int Dent J 2024:S0020-6539(24)00139-4. [PMID: 38839530 DOI: 10.1016/j.identj.2024.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 04/21/2024] [Accepted: 05/07/2024] [Indexed: 06/07/2024] Open
Abstract
BACKGROUND AND OBJECTIVE In the literature, no studies correlate the effects of mandibular advancement devices (MADs) with different titration systems to periodontitis. Through a finite element analysis (FEA), this study investigates the effects generated on periodontal ligaments (PDLs) and teeth by four commercial MADs in periodontal health and with 15% bone resorption. METHODS Four MADs (Somnodent Flex™, Somnodent Avant™, Orthoapnea™, and Herbst™) were digitalised starting from the impressions of a patient's dental arches. A force of 11.18 N, representing an advancement of 9.5 mm, was applied, and a FEA was subsequently performed. After measuring the stresses and displacements on the PDLs and teeth in healthy periodontal conditions, the vertical dimension of the alveolar bone was reduced by 15%, and measurements were repeated. RESULTS In terms of PDL stress, Herbst™ is the device which guarantees a more uniform increment in case of the first stage of periodontitis (+7% for mandibular and maxillary PDLs compared to the healthy condition). For Somnodent™ devices, the PDLs stress increment is almost null for mandibular PDLs but much higher than Herbst™ for maxillary PDLs (+17% and +21% for Flex™ and Avant™). Orthoapnea™ determines a PDL stress augmentation between the other devices (+16% and +7%, respectively, for maxillary and mandibular PDLs). Concerning teeth movement, Herbst™ and Orthoapnea™ determine a lower and more uniform displacement than Somnodent devices. CONCLUSIONS The stress distribution and teeth displacement are strictly related to MAD geometry. Since its minor effects on teeth and PDLs, the Herbst™ could be more appropriate in patients with periodontitis.
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Affiliation(s)
- Manila Caragiuli
- Department of Industrial Engineering and Mathematical Sciences, Università Politecnica delle Marche, Ancona, Italy.
| | - Mara Candelari
- Department of Industrial Engineering and Mathematical Sciences, Università Politecnica delle Marche, Ancona, Italy
| | - Francesca Zalunardo
- Department of Neuroscience, Dental Clinic, Section of Dentistry, University of Padua, Padua, Italy
| | - Giovanni Bruno
- Department of Neuroscience, Dental Clinic, Section of Dentistry, University of Padua, Padua, Italy; Department of Industrial Engineering, University Tor Vergata, Rome, Italy
| | - Alberto De Stefani
- Department of Neuroscience, Dental Clinic, Section of Dentistry, University of Padua, Padua, Italy; Department of Pharmacological Sciences, University of Padua, Padua, Italy
| | - Agnese Brunzini
- Department of Industrial Engineering and Mathematical Sciences, Università Politecnica delle Marche, Ancona, Italy
| | - Marco Mandolini
- Department of Industrial Engineering and Mathematical Sciences, Università Politecnica delle Marche, Ancona, Italy
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Elshazly TM, Bourauel C, Chavanne P, Elattar H, Keilig L. Numerical biomechanical finite element analysis of different trimming line designs of orthodontic aligners: An in silico study. J World Fed Orthod 2024; 13:65-71. [PMID: 38395726 DOI: 10.1016/j.ejwf.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 12/23/2023] [Accepted: 01/03/2024] [Indexed: 02/25/2024]
Abstract
BACKGROUND A finite element model was used to investigate the effect of different designs and thicknesses of orthodontic aligner margins on their biomechanical behavior. METHODS A three-dimensional data set of an upper jaw was imported into the 3-matic software. The upper right central incisor tooth (Tooth 11) was separated from the remaining model, and its periodontal ligament and surrounding bone were designed. Aligners were designed with four different trimming lines (scalloped, straight, scalloped extended, straight extended), each with four different thicknesses (0.3, 0.4, 0.5, and 0.6 mm). The models were imported into a finite element package (Marc/Mentat). A linear elastic constitutive material model was applied. A facial 0.2 mm bodily malalignment of tooth 11 was simulated. RESULTS The maximum resultant force was in the range of 1.0 N to 2.2 N. The straight trimming designs deliver higher resultant forces compared with scalloped trimming designs. Increasing the aligner thickness and/or extending the aligner edge beyond the gingival line leads to an increase in the resultant force. All designs showed an uneven distribution of the normal contact forces over the tooth surface with a predominant concentration toward the cervical third and distal third, particularly with the extended trimming designs. All designs showed uncontrolled tipping of the tooth. CONCLUSIONS Based on the current model outcomes, the use of a straight extended trimming line design for aligners is favored because of its positive impact on force distribution and, consequently, the control of tooth movement. CLINICAL RELEVANCE These findings provide aligner companies and orthodontists a valuable biomechanical evidence and guidance to enhance control over tooth movement and therefore optimize treatment outcomes. This can be achieved by trimming the edges of aligners with a straight extended design and selecting the appropriate aligner thickness.
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Affiliation(s)
- Tarek M Elshazly
- Oral Technology, Dental School, University Hospital Bonn, Bonn, Germany.
| | | | | | - Hanaa Elattar
- Orthodontic Department, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt
| | - Ludger Keilig
- Oral Technology, Dental School, University Hospital Bonn, Bonn, Germany; Department of Dental Prosthetics, Propaedeutics and Materials Science, Dental School, University Hospital Bonn, Bonn, Germany
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Martin L, Jain P, Ferguson Z, Gholamalizadeh T, Moshfeghifar F, Erleben K, Panozzo D, Abramowitch S, Schneider T. A systematic comparison between FEBio and PolyFEM for biomechanical systems. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 244:107938. [PMID: 38056313 PMCID: PMC10843651 DOI: 10.1016/j.cmpb.2023.107938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 10/30/2023] [Accepted: 11/20/2023] [Indexed: 12/08/2023]
Abstract
BACKGROUND AND OBJECTIVES Finite element simulations are widely employed as a non-invasive and cost-effective approach for predicting outcomes in biomechanical simulations. However, traditional finite element software, primarily designed for engineering materials, often encountered limitations in contact detection and enforcement, leading to simulation failure when dealing with complex biomechanical configurations. Currently, a lot of model tuning is required to get physically accurate finite element simulations without failures. This adds significant human interaction to each iteration of a biomechanical model. This study addressed these issues by introducing PolyFEM, a novel finite element solver that guarantees inversion- and intersection-free solutions with completely automatic collision detection. The objective of this research is to validate PolyFEM's capabilities by comparing its results with those obtained from a well-established finite element solver, FEBio. METHODS To achieve this goal, five comparison scenarios were formulated to assess and validate PolyFEM's performance. The simulations were reproduced using both PolyFEM and FEBio, and the final results were compared. The five comparison scenarios included: (1) reproducing simulations from the FEBio test suite, consisting of static, dynamic, and contact-driven simulations; (2) replicating simulations from the verification paper published alongside the original release of FEBio; (3) a biomechanically based contact problem; (4) creating a custom simulation involving high-energy collisions between soft materials to highlight the difference in collision methods between the two solvers; and (5) performing biomechanical simulations of biting and quasi-stance. RESULTS We found that PolyFEM was capable of replicating all simulations previously conducted in FEBio. Particularly noteworthy is PolyFEM's superiority in high-energy contact simulations, where FEBio fell short, unable to complete over half of the simulations in Scenario 4. Although some of the simulations required significantly more simulation time in PolyFEM compared to FEBio, it is important to highlight that PolyFEM achieved these results without the need for any additional model tuning or contact declaration. DISCUSSION Despite being in the early stages of development, PolyFEM currently provides verified solutions for hyperelastic materials that are consistent with FEBio, both in previously published workflows and novel finite element scenarios. PolyFEM exhibited the ability to tackle challenging biomechanical problems where other solvers fell short, thus offering the potential to enhance the accuracy and realism of future finite element analyses.
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Affiliation(s)
- Liam Martin
- University of Pittsburgh Swanson School of Engineering, USA
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Jin X, Tian X, Lee Zhi Hui V, Zheng Y, Song J, Han X. The effect of enhanced structure in the posterior segment of clear aligners during anterior retraction: a three-dimensional finite element and experimental model analysis. Prog Orthod 2024; 25:3. [PMID: 38221549 PMCID: PMC10788328 DOI: 10.1186/s40510-023-00502-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 11/21/2023] [Indexed: 01/16/2024] Open
Abstract
BACKGROUND Mesial tipping of posterior teeth occurs frequently during space closure with clear aligners (CAs). In this study, we proposed a new modification of CA by localized thickening of the aligner to form the enhanced structure and investigate its biomechanical effect during anterior retraction. METHODS Two methods were employed in this study. First, a finite element (FE) model was constructed, which included alveolar bone, the first premolars extracted maxillary dentition, periodontal ligaments (PDL), attachments and aligners. The second method involved an experimental model-a measuring device using multi-axis transducers and vacuum thermoforming aligners. Two groups were formed: (1) The control group used common CAs and (2) the enhanced structure group used partially thickened CAs. RESULTS FE model revealed that the enhanced structure improved the biomechanics during anterior retraction. Specifically, the second premolar, which had a smaller PDL area, experienced a smaller protraction force and moment, making it less likely to tip mesially. In the same vein, the molars could resist movement due to their larger PDL area even though they were applied larger forces. The resultant force of the posterior tooth was closer to the center of resistance, reducing the tipping moment. The canine was applied a larger retraction force and moment, resulting in sufficient retraction of anterior teeth. The experimental model demonstrated a similar trend in force variation as the FE model. CONCLUSIONS Enhanced structure allowed force distribution more in accordance with optimal principles of biomechanics during the extraction space closure while permitting less mesial tipping and anchorage loss of posterior teeth and better retraction of anterior teeth. Thus, enhanced structure alleviated the roller coaster effect associated with extraction cases and offered a new possibility for anchorage reinforcement in clear aligner therapy.
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Affiliation(s)
- Xiaohan Jin
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, 14# 3Rd Section of Ren Min Nan Road, Chengdu, 610041, Sichuan Province, China
| | - Xue Tian
- Jiangmen Municipal Stomatology Hospital, Yongli Street, Shengli Road, Jiangmen, 529000, Guangdong Province, China
| | - Victoria Lee Zhi Hui
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, 14# 3Rd Section of Ren Min Nan Road, Chengdu, 610041, Sichuan Province, China
| | - Yikan Zheng
- R&D Center, EA Medical Center Device Technologies Co., Ltd, Middle Branch Road, Wuxi, 214174, Jiangsu Province, China
| | - Jinlin Song
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital of Chongqing Medical University, Chongqing Medical University, 426# Songshibei Road, Chongqing, China
| | - Xianglong Han
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, 14# 3Rd Section of Ren Min Nan Road, Chengdu, 610041, Sichuan Province, China.
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Xia Q, Wang W, Wang C, Feng G, Wang C, Song J, Fan Y. Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study. BMC Oral Health 2024; 24:80. [PMID: 38218801 PMCID: PMC10787995 DOI: 10.1186/s12903-023-03704-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/22/2023] [Indexed: 01/15/2024] Open
Abstract
BACKGROUND The aim of this study is to conduct a comparative evaluation of different designs of clear aligners and examine the disparities between clear aligners and fixed appliances. METHODS 3D digital models were created, consisting of a maxillary dentition without first premolars, maxilla, periodontal ligaments, attachments, micro-implant, 3D printed lingual retractor, brackets, archwire and clear aligner. The study involved the creation of five design models for clear aligner maxillary anterior internal retraction and one design model for fixed appliance maxillary anterior internal retraction, which were subsequently subjected to finite element analysis. These design models included: (1) Model C0 Control, (2) Model C1 Posterior Micro-implant, (3) Model C2 Anterior Micro-implant, (4) Model C3 Palatal Plate, (5) Model C4 Lingual Retractor, and (6) Model F0 Fixed Appliance. RESULTS In the clear aligner models, a consistent pattern of tooth movement was observed. Notably, among all tested models, the modified clear aligner Model C3 exhibited the smallest differences in sagittal displacement of the crown-root of the central incisor, vertical displacement of the central incisor, sagittal displacement of the second premolar and second molar, as well as vertical displacement of posterior teeth. However, distinct variations in tooth movement trends were observed between the clear aligner models and the fixed appliance model. Furthermore, compared to the fixed appliance model, significant increases in tooth displacement were achieved with the use of clear aligner models. CONCLUSIONS In the clear aligner models, the movement trend of the teeth remained consistent, but there were variations in the amount of tooth displacement. Overall, the Model C3 exhibited better torque control and provided greater protection for posterior anchorage teeth compared to the other four clear aligner models. On the other hand, the fixed appliance model provides superior anterior torque control and better protection of the posterior anchorage teeth compared to clear aligner models. The clear aligner approach and the fixed appliance approach still exhibit a disparity; nevertheless, this study offers a developmental direction and establishes a theoretical foundation for future non-invasive, aesthetically pleasing, comfortable, and efficient modalities of clear aligner treatment.
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Affiliation(s)
- Qian Xia
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Weixu Wang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Chunjuan Wang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Ge Feng
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Chao Wang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China.
- Key Laboratory of Biomechanics and Mechanobiology, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, State Key Laboratory of Virtual Reality Technology and Systems, Ministry of Education, Beihang University, No.37, Xueyuan Road, Beijing, 100083, China.
| | - Jinlin Song
- Stomatological Hospital of Chongqing Medical University, Chongqing, China.
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China.
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China.
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, State Key Laboratory of Virtual Reality Technology and Systems, Ministry of Education, Beihang University, No.37, Xueyuan Road, Beijing, 100083, China
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Sen Yavuz B, Yilmaz A, Haznedaroglu E, Sezer B, Okutan AE, Sezgin BI, Ozcelik M, Sezgin GI, Ugurlu F, Mentes A. Retrospective evaluation of traction time for impacted dilacerated maxillary central incisors in mixed dentition. JOURNAL OF STOMATOLOGY, ORAL AND MAXILLOFACIAL SURGERY 2023; 124:101485. [PMID: 37116703 DOI: 10.1016/j.jormas.2023.101485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/09/2023] [Accepted: 04/24/2023] [Indexed: 04/30/2023]
Abstract
PURPOSES This study aimed to contribute to understanding the factors affecting the time of traction treatment of impacted dilacerated maxillary central incisors. METHODS This retrospective study included children aged 8 - 11 years with a history of trauma, who applied to the pediatric dentistry clinics of Marmara University, School of Dentistry, between December 2013 and December 2019, and were treated for unilateral impacted dilacerated maxillary upper central incisors. Children's age, sex, digital panoramic radiographs, cone-beam computed tomography, and intraoral photographs were retrieved from electronic dental health records. The effects of children's age, sex, the direction of impacted teeth, distance of the teeth to the top of the alveolar crest, and root dilaceration level on traction time were analyzed by Mann-Whitney U test and Spearman's rank correlation coefficient test. RESULTS The inverse position of the incisors significantly increased the traction time (P = 0.012). However, the traction time did not differ according to the sex of the children (P = 0.707) or the level of root dilaceration (P = 0.429). No correlation was observed between the traction time and the age of children (P = 0.644) or the distance of the incisors from the top of the alveolar crest (P = 0.397). CONCLUSIONS In cases of the forced eruption of for the impacted dilacerated maxillary central incisors, the direction of the teeth should be evaluated when deciding on the treatment plan, as it may affect the treatment time.
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Affiliation(s)
- Betul Sen Yavuz
- Department of Pediatric Dentistry, School of Dentistry, Marmara University, Istanbul, Turkey.
| | - Ahu Yilmaz
- Department of Pediatric Dentistry, School of Dentistry, Marmara University, Istanbul, Turkey
| | - Eda Haznedaroglu
- Department of Pediatric Dentistry, School of Dentistry, Marmara University, Istanbul, Turkey
| | - Berkant Sezer
- Department of Pediatric Dentistry, School of Dentistry, Çanakkale Onsekiz Mart University, Çanakkale, Turkey
| | - Alev Eda Okutan
- Department of Pediatric Dentistry, School of Dentistry, Istanbul Atlas University, Istanbul, Turkey
| | - Batin Ilgit Sezgin
- Department of Pediatric Dentistry, School of Dentistry, Istanbul Kent University, Istanbul, Turkey
| | - Mert Ozcelik
- Department of Pediatric Dentistry, School of Dentistry, Istanbul Istinye University, Istanbul, Turkey
| | | | - Faysal Ugurlu
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Marmara University, Istanbul, Turkey
| | - Ali Mentes
- Department of Pediatric Dentistry, School of Dentistry, Marmara University, Istanbul, Turkey
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Liu X, Wu J, Cheng Y, Gao J, Wen Y, Zhang Y, Luo H, Jin Z, Ma Y. Effective contribution ratio of the molar during sequential distalization using clear aligners and micro-implant anchorage: a finite element study. Prog Orthod 2023; 24:35. [PMID: 37806991 PMCID: PMC10560653 DOI: 10.1186/s40510-023-00485-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 08/03/2023] [Indexed: 10/10/2023] Open
Abstract
INTRODUCTION This study aims to investigate the biomechanical effects of anchorage reinforcement using clear aligners (CAs) with microimplants during molar distalization. And also explores potential clinical strategies for enhancing anchorage in the sequential distalization process. METHODS Finite element models were established to simulate the CAs, microimplants, upper dentition, periodontal ligament (PDL), and alveolar bone. In group set I, the 2nd molars underwent a distal movement of 0.25 mm in group set II, the 1st molars were distalized by 0.25 mm after the 2nd molars had been placed to a target position. Each group set consisted of three models: Model A served as the control model, Model B simulated the use of microimplants attached to the aligner through precision cuts, and Model C simulated the use of microimplants attached by buttons. Models B and C were subjected to a series of traction forces. We analyzed the effective contribution ratios of molar distalization, PDL hydrostatic stress, and von Mises stress of alveolar bone. RESULTS The distalization of the 2nd molars accounted for a mere 52.86% of the 0.25-mm step distance without any reinforcement of anchorage. The remaining percentage was attributed to the mesial movement of anchorage teeth and other undesired movements. Models B and C exhibited an increased effective contribution ratio of molar distalization and a decreased loss of anchorage. However, there was a slight increase in the undesired movement of molar tipping and rotation. In group set II, the 2nd molar displayed a phenomenon of mesial relapse due to the reciprocal force produced by the 1st molar distalization. Moreover, the efficacy of molar distalization in terms of contribution ratio was found to be positively correlated with the magnitude of force applied. In cases where stronger anchorage reinforcement is required, precision cuts is the superior method. CONCLUSIONS The utilization of microimplants in conjunction with CAs can facilitate the effective contribution ratio of molar distalization. However, it is important to note that complete elimination of anchorage loss is not achievable. To mitigate undesired movement, careful planning of anchorage preparation and overcorrection is recommended.
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Affiliation(s)
- Xulin Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, 710032, China
| | - Junjie Wu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, 710032, China
| | - Yuxun Cheng
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, 710032, China
| | - Jie Gao
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, 710032, China
| | - Yi Wen
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, 710032, China
| | - Yubohan Zhang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, 710032, China
| | - Houzhuo Luo
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, 710032, China
| | - Zuolin Jin
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, 710032, China.
| | - Yanning Ma
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, 710032, China.
- Shanxi Medical University School and Hospital of Stomatology, Taiyuan, 030001, China.
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Liu X, Wang W, Gao J, Qin W, Wen Y, Luo H, Ma Y, Jin Z. Actual contribution ratio of maxillary and mandibular molars for total molar relationship correction during maxillary molar sequential distalization using clear aligners with Class II elastics: A finite element analysis. Am J Orthod Dentofacial Orthop 2023; 164:e106-e120. [PMID: 37610384 DOI: 10.1016/j.ajodo.2023.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 07/01/2023] [Accepted: 07/01/2023] [Indexed: 08/24/2023]
Abstract
INTRODUCTION Class II elastics, in combination with clear aligners (CA), are efficient for molar distalization. However, the effects of this combination on intermaxillary molar relationship correction have yet to be investigated. This study aimed to investigate the actual contribution ratio of the maxillary and mandibular molars for total molar relationship correction during maxillary molar distalization using Class II elastics with CA and further explore therapeutic recommendations for clinical practice. METHODS Finite element models (FEMs) were established, including the distalization of the second molars (Set I), followed by the distalization of the first molars (Set II). Model A simulated elastics attached by precision cutting, whereas Model B simulated elastics attached to buttons. Force magnitudes of 100 g, 150 g, and 200 g of force were applied. We recorded the contribution ratio of the maxillary and mandibular molars for total molar relationship correction, effective distalizing distance in 0.25 mm step distance, tipping and rotation angles, and the hydrostatic stress in the periodontal ligament. RESULTS During maxillary molar distalization, mesialization of the mandibular molar had a notable contribution ratio for molar relationship correction. The mandibular first molar was mesialized with mesiolingual rotation tendency. Approximately half of the 0.25 mm step distance was occupied by maxillary molar distalization; the remainder was occupied by anchorage teeth mesialization and tipping or rotation. When traction forces increased, the total molar relationship correction and effective distalization increased; the mandibular molars mesialization contribution ratio also increased, as did rotation and inclination tendency. Precision cutting had a higher total molar relationship correction and more effective distalization than a button but also had a larger contribution ratio of mandibular molar mesialization and inclination or rotation. CONCLUSIONS Mandibular molar mesialization should be considered when correcting the molar relationship using CA with intermaxillary elastics during maxillary molar distalization. It is also important to consider the anchorage teeth mesialization and undesired tipping or rotation.
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Affiliation(s)
- Xulin Liu
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, China
| | - Wei Wang
- Shanxi Medical University School and Hospital of Stomatology, Taiyuan, China
| | - Jie Gao
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, China
| | - Wen Qin
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, China
| | - Yi Wen
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, China
| | - Houzhuo Luo
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, China
| | - Yanning Ma
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, China; Shanxi Medical University School and Hospital of Stomatology, Taiyuan, China.
| | - Zuolin Jin
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, China.
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Dotzer B, Stocker T, Wichelhaus A, Janjic Rankovic M, Sabbagh H. Biomechanical simulation of forces and moments of initial orthodontic tooth movement in dependence on the used archwire system by ROSS (Robot Orthodontic Measurement & Simulation System). J Mech Behav Biomed Mater 2023; 144:105960. [PMID: 37348170 DOI: 10.1016/j.jmbbm.2023.105960] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/24/2023]
Abstract
OBJECTIVES Aim of this study was to determine the forces and moments during simulated initial orthodontic tooth movements using a novel biomechanical test setup. METHODS The test setup consisted of an industrial precision robot with a force-torque sensor, a maxillary model and a control computer and software. Forces and moments acting on the corresponding experimental tooth during the motion simulations were dynamically measured for two 0.016" NiTi round archwires (Sentalloy Light/Sentalloy Medium). Intrusive (#1), rotational (#2) and angular (#3) tooth movements were simulated by a control program based on the principle of force control and executed by the robot. The results were statistically analysed using K-S-test and Mann-Whitney U test with a significance level of α = 5%. RESULTS Sentalloy Medium archwires generated higher forces and moments than the Sentalloy Light archwires in all simulations. In simulation #1 the mean initial forces/moments reached 1.442 N/6.781 Nmm for the Light archwires and 1.637 N/9.609 Nmm for the Medium archwires. In movement #2 Light archwires generated mean initial forces/moments of 0.302 N/-8.271 Nmm whereas Medium archwires generated 0.432 N/-9.653 Nmm. Simulation #3 showed mean initial forces/moments of -0.122 N/8.477 Nmm from the Light archwires compared to -0.300 N/11.486 Nmm for the Medium archwires. SIGNIFICANCE The measured forces and moments were suitable for initial orthodontic tooth movement in simulations #2 and #3, however inadequate in simulation #1. Reduced archwire dimensions (<0.016″) should be selected for initial leveling of vertical malocclusions.
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Affiliation(s)
- Benedikt Dotzer
- Department of Orthodontics and Dentofacial Orthopedics, University Hospital, LMU Munich, Goethestrasse 70, Munich 80336, Germany
| | - Thomas Stocker
- Department of Orthodontics and Dentofacial Orthopedics, University Hospital, LMU Munich, Goethestrasse 70, Munich 80336, Germany
| | - Andrea Wichelhaus
- Department of Orthodontics and Dentofacial Orthopedics, University Hospital, LMU Munich, Goethestrasse 70, Munich 80336, Germany
| | - Mila Janjic Rankovic
- Department of Orthodontics and Dentofacial Orthopedics, University Hospital, LMU Munich, Goethestrasse 70, Munich 80336, Germany
| | - Hisham Sabbagh
- Department of Orthodontics and Dentofacial Orthopedics, University Hospital, LMU Munich, Goethestrasse 70, Munich 80336, Germany.
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Mao B, Tian Y, Xiao Y, Li J, Zhou Y. The effect of maxillary molar distalization with clear aligner: a 4D finite-element study with staging simulation. Prog Orthod 2023; 24:16. [PMID: 37183221 PMCID: PMC10183381 DOI: 10.1186/s40510-023-00468-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 04/08/2023] [Indexed: 05/16/2023] Open
Abstract
INTRODUCTION Long-term simulation of tooth movement is crucial for clear aligner (CA) treatment. This study aimed to investigate the effect of maxillary molar distalization with CA via an automatic staging simulation. METHOD A finite-element method (FEM) model of maxillary dentition, periodontal ligaments, attachments, and corresponding CA was established, and a prescribed 2-mm distalization with 0.1 mm each step of the second molar was simulated. The long-term tooth movement under orthodontic force was simulated with an iterative computation method. The morphologic changes of CA during staging were simulated with the thermal expansion method. RESULTS Twenty steps of molar distalization were simulated. Significant distal tilting of the second molar was revealed, along with the proclination of anterior teeth, which caused the 'reversed bow effect'. For the second molar, 4.63°distal tilting at the 20th step was revealed. The intrusion of the incisors and the second molar were 0.43 mm, 0.39 mm, and 0.45 mm, respectively, at step 20. All the anterior teeth showed a proclination of approximately 1.41°-2.01° at the 20th step. The expression rate of the designed distalization of the second molar was relatively low (approximately 68%) compared to the high efficacy of interdental space opening between molars with CA (approximately 89%). CONCLUSION A novel method of simulating long-term molar distalization with CA with FEM was developed. The FEM results suggested distal tilting of the second molar and the proclination of anterior teeth during the molar distalization.
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Affiliation(s)
- Bochun Mao
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health, No.22 Zhongguancun South Avenue, Haidian District, Beijing, 100081, People's Republic of China
| | - Yajing Tian
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health, No.22 Zhongguancun South Avenue, Haidian District, Beijing, 100081, People's Republic of China
| | - Yujia Xiao
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health, No.22 Zhongguancun South Avenue, Haidian District, Beijing, 100081, People's Republic of China
| | - Jing Li
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health, No.22 Zhongguancun South Avenue, Haidian District, Beijing, 100081, People's Republic of China.
| | - Yanheng Zhou
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health, No.22 Zhongguancun South Avenue, Haidian District, Beijing, 100081, People's Republic of China
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Yang Y, Yang R, Liu L, Zhang X, Jiang Q, Fan Q, Zhang H, Long H, Lai W. The effects of aligner anchorage preparation on mandibular first molars during premolar-extraction space closure with clear aligners: A finite element study. Am J Orthod Dentofacial Orthop 2023:S0889-5406(23)00098-7. [PMID: 37024337 DOI: 10.1016/j.ajodo.2022.12.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 12/01/2022] [Accepted: 12/01/2022] [Indexed: 04/08/2023]
Abstract
INTRODUCTION This study aimed to determine the effectiveness of different aligner anchorage preparations on mandibular first molars during premolar-extraction space closure with clear aligners and to assess the effects of different modes of Class II elastics on mandibular first molars. METHODS Finite element models were constructed on the basis of cone-beam computed tomography data from an orthodontic patient. The models comprised maxilla, mandible, maxillary and mandibular teeth without first premolars, periodontal ligaments, attachments and aligners. Tooth displacement tendencies were calculated using different aligner anchorage preparations and Class II elastics on the models from the same patient. Three group sets were designed on the basis of the positions of aligner cutouts and buttons (mesiobuccal, distobuccal and lingual). Four groups were established in each of the 3 group sets. Four groups were created: (1) no elastic traction + no anchorage preparation, (2) anchorage preparation only, (3) elastic traction only, and (4) elastic traction + anchorage preparation. Different aligner anchorage preparations (0°, 1°, 2°, 3°) were applied on mandibular second premolars and molars. The Class II traction force was set to 100 g. RESULTS With clear aligners, mandibular first molars were subject to mesial tipping, lingual tipping and intrusion. In the condition of no elastic traction, aligner anchorage preparation resulted in distal tipping, buccal tipping, and extrusion effect on mandibular first molars. Aligner anchorage preparation was more effective in the distal and lingual cutout groups than in the mesial cutout group. In the condition of Class II elastic traction, the bodily movement of mandibular first molars was achieved with a 3° anchorage preparation for the mesial cutout group and a 1.7° anchorage preparation for distal and lingual cutout groups. Absolute maximal anchorage was achieved with a 2° anchorage preparation for distal and lingual cutout groups. CONCLUSIONS Clear aligner therapy caused mesial tipping, lingual tipping and intrusion of mandibular first molars during premolar-extraction space closure. Aligner anchorage preparation effectively prevented mesial and lingual tipping of mandibular molars. Distal and lingual cutout modes were more effective than mesial cutout modes in aligner anchorage preparation. For each aligner stage (0.25 mm), 1.7° aligner anchorage preparation and Class II elastics with distal or lingual cutouts led to the bodily movement of mandibular first molars, whereas 2° anchorage preparation reached absolute maximal anchorage.
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Affiliation(s)
- Yi Yang
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ruicong Yang
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China
| | - Lu Liu
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xiaoqi Zhang
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qingsong Jiang
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qi Fan
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Haoxin Zhang
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hu Long
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
| | - Wenli Lai
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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Analysis for Predictors of Failure of Orthodontic Mini-implant Using Patient-Specific Finite Element Models. Ann Biomed Eng 2023; 51:594-603. [PMID: 36167866 DOI: 10.1007/s10439-022-03067-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 08/27/2022] [Indexed: 11/01/2022]
Abstract
In this study, we analyzed the clinical factors and mechanical parameters for predicting orthodontic mini-implant (OMI) failure in the mandible, which has different properties from the maxilla. A patient-specific finite element analysis was applied to 32 OMIs (6 failures and 26 successes) implanted between the mandibular second premolars and first molars used for anchorage. The peak stress and strain parameters were calculated for each sample. A logistic regression of the failure (vs. success) of OMIs on the mechanical parameters in the models was conducted. In addition, the influence of clinical factors on the mechanical parameters considered to be related to OMI failure was examined by a regression analysis. The mechanical parameter which best predicts OMI failure in the mandible was found to be a minimum principal strain of between 0.5 to 1.0 mm from the OMI surface (R2 = 0.8033). The results indicate the patient's bone density, distance between the OMIs and adjacent root, and vertical implantation angle of the OMIs are potential clinical predictors of OMI failure in the mandible.
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Ritchie C, McGregor S, Bearn DR. Temporary anchorage devices and the forces and effects on the dentition and surrounding structures during orthodontic treatment: a scoping review. Eur J Orthod 2023; 45:324-337. [PMID: 36763546 DOI: 10.1093/ejo/cjac072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
BACKGROUND Temporary anchorage devices (TADs) offer the clinician an immediate temporary source of skeletal anchorage for a range of orthodontic interventions. It is important to understand forces involved in using TADs and the effects on the dentition and surrounding structures, to improve clinical outcomes. OBJECTIVE To examine and qualitatively synthesize literature on the forces involved with the use of TADs and the effects on the dentition and surrounding structures in orthodontic tooth movement, to provide better understanding of the complex interactions and the clinical implications. SEARCH METHODS Electronic databases searched included: Cochrane Library [including Central Register of Controlled Trials (CENTRAL)], Embase via OVID, Pubmed, and Scopus. Study screening and selection were conducted in duplicate. SELECTION CRITERIA Studies selected were clinical studies, simulation studies (computer or laboratory-based), or animal studies with no restriction over gender, age, study type (excluding case reports), or setting. Studies focusing on the forces involved with the use of TADs in orthodontic treatment and their effects on the dentition and surrounding structures were included. DATA COLLECTION AND ANALYSIS A data charting form was piloted and refined. Data charting was performed independently and in duplicate. This consisted of key fields with predetermined options and free text. The extracted data were collated, and a narrative synthesis conducted. RESULTS The results from 203 included studies were grouped into seven TAD based interventions combining the clinical, simulation, and animal studies. They were: En masse retraction of anterior teeth, intrusion, movement of a single tooth, orthopaedic interventions, distalisation, maxillary expansion and other types. The forces involved with the use of TADs, and their effects on the dentition and surrounding structures, were presented in descriptive and tabular formats. LIMITATIONS This review restricted study language to English. Formal appraisal of the quality of evidence is not a required feature of scoping reviews, as per the PRISMA-ScR guidelines, however it was evident that a proportion of clinical studies were of high risk of bias and low quality and therefore any proposed changes the reader may consider to their clinical practice should be contextualized in light of this. CONCLUSIONS Across the seven types of TAD based interventions the effects on the dentition and surrounding structures are described providing a better understanding of the complex interactions. A guide to the level and direction of forces in each type of intervention is provided to aid clinicians in achieving high quality outcomes. IMPLICATIONS There is a need to validate future FEA simulation studies by comparing to clinical data. It is also recommended that future scoping reviews incorporate a formal critical appraisal of studies to facilitate the translation of the results into clinical practice. Development of a standard set of terms for TADs is recommended to facilitate future research. REGISTRATION Registration of a scoping review is not possible with PROSPERO. FUNDING None to declare.
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Affiliation(s)
- Colin Ritchie
- Orthodontic Department, Dundee Dental Hospital and Research School, University of Dundee, Scotland
| | - Scott McGregor
- Library & Learning Centre, University of Dundee, Scotland
| | - David R Bearn
- Orthodontic Department, University of Dundee, Scotland
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Jia L, Wang C, Li L, He Y, Wang C, Song J, Wang L, Fan Y. The effects of lingual buttons, precision cuts, and patient-specific attachments during maxillary molar distalization with clear aligners: Comparison of finite element analysis. Am J Orthod Dentofacial Orthop 2023; 163:e1-e12. [PMID: 36435687 DOI: 10.1016/j.ajodo.2022.10.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 09/16/2022] [Accepted: 10/10/2022] [Indexed: 11/25/2022]
Abstract
INTRODUCTION This study aimed to analyze the biomechanical effects of the combined use of clear aligners (CA) and auxiliaries (precision cuts, lingual buttons, and patient-specific attachments) on mesial tipping and extrusion of the premolars during maxillary molars distalization. METHODS Three-dimensional finite element method was employed to simulate clinical scenarios of CA with different auxiliaries for molar distalization. As such, 200 g of distal force was applied to the microimplants from the notches, lingual buttons, and hooks. Orthodontic tooth movement and the hydrostatic pressure in the periodontal ligament were compared. RESULTS Adding auxiliaries can provide the maxillary arch anchorage and promote the distal tipping of premolars and retroclination of maxillary incisors. In contrast, this effect was more pronounced in patient-specific attachment applications than in other types of auxiliaries. The independent application of the CA caused mesial tipping and extrusion of the premolar and also caused the incisor proclination. CONCLUSIONS The anchorage loss caused by the CA alone could be alleviated with the assistance of auxiliaries. Notably, patient-specific attachments further reinforce the anchorage of the anterior arch by incorporating anchor teeth as 1 anchorage unit.
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Affiliation(s)
- Lurong Jia
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China; Stomatological Hospital of Chongqing Medical University, Chongqing, China; Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Chunjuan Wang
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China; Stomatological Hospital of Chongqing Medical University, Chongqing, China; Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Lingjie Li
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China; Stomatological Hospital of Chongqing Medical University, Chongqing, China; Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Yao He
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China; Stomatological Hospital of Chongqing Medical University, Chongqing, China; Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Chao Wang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China; Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, China.
| | - Jinlin Song
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China; Stomatological Hospital of Chongqing Medical University, Chongqing, China; Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China.
| | - Lizhen Wang
- Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, China
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, China
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Gil-Marques B, Pallarés-Sabater A, Brizuela-Velasco A, Sánchez Lasheras F, Lázaro-Calvo P, Gómez-Adrián MD, Larrazábal-Morón C. A Biomechanical Analysis of the Influence of the Morfology of the Bone Blocks Grafts on the Transfer of Tension or Load to the Soft Tissue by Means of the Finite Elements Method. MATERIALS (BASEL, SWITZERLAND) 2022; 15:9039. [PMID: 36556844 PMCID: PMC9786190 DOI: 10.3390/ma15249039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/06/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Edentulism produces resorption of alveolar bone processes, which can complicate placement of dental implants. Guided bone regeneration techniques aim to recover the volume of bone. These treatments are susceptible to the surgical technique employed, the design of the autologous block or the tension of the suture. These factors can relate to major complications as the lack of primary closure and dehiscence. The present study, using finite element analysis, aimed to determine differences in terms of displacement of the oral mucosa, transferred stress according to Von Mises and deformation of soft tissue when two block graft designs (right-angled and rounded) and two levels of suture tension (0.05 and 0.2 N) were combined. The results showed that all the variables analyzed were greater with 0.2 N. Regarding the design of the block, no difference was found in the transferred stress and deformation of the soft tissue. However, displacement was related to a tendency to dehiscence (25% greater in the right-angled/chamfer design). In conclusion different biomechanical behavior was observed in the block graft depending on the design and suture tension, so it is recommended to use low suture tension and rounded design. A novel finite element analysis model is presented for future investigations.
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Affiliation(s)
- Blanca Gil-Marques
- Doctoral School, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain
- School of Dentistry, Departament Medical and Surgery, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain
| | - Antonio Pallarés-Sabater
- Departament Endodonthics, School of Dentistry, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain
| | | | - Fernando Sánchez Lasheras
- Department of Mathematics, Faculty of Sciences, University of Oviedo, 33007 Oviedo, Spain
- Institute of Space Sciences and Technologies of Asturias (ICTEA), University of Oviedo, 33004 Oviedo, Spain
| | - Pedro Lázaro-Calvo
- Departament of Periodonticx, Complutense University, 28004 Madrid, Spain
| | - María Dolores Gómez-Adrián
- School of Dentistry, Departament Medical and Surgery, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain
| | - Carolina Larrazábal-Morón
- School of Dentistry, Departament Medical and Surgery, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain
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Liu X, Cheng Y, Qin W, Fang S, Wang W, Ma Y, Jin Z. Effects of upper-molar distalization using clear aligners in combination with Class II elastics: a three-dimensional finite element analysis. BMC Oral Health 2022; 22:546. [PMID: 36456944 PMCID: PMC9714146 DOI: 10.1186/s12903-022-02526-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 10/21/2022] [Indexed: 12/03/2022] Open
Abstract
INTRODUCTION The effects of upper-molar distalization using clear aligners in combination with Class II elastics for anchorage reinforcement have not been fully investigated yet. The objective of this study is to analyze the movement and stress of the whole dentition and further explore guidelines for the selection of traction methods. METHODS Three-dimensional (3D) finite element models are established to simulate the sequential molar distalization process, including the initial distalization of the 2nd molar (Set I) and the initial distalization of the 1st molar (Set II). Each group set features three models: a control model without Class II elastics (model A), Class II elastics attached to the tooth by buttons (model B), and Class II elastics attached to the aligner by precision cutting (model C). The 3D displacements, proclination angles, periodontal ligament (PDL) hydrostatic stress and alveolar bone von Mises stress in the anterior area are recorded. RESULTS In all of the models, the maxillary anterior teeth are labial and mesial proclined, whereas the distal moving molars exhibit distal buccal inclination with an extrusion tendency. With the combination of Class II elastics, the anchorage was effectively reinforced; model C demonstrates superior anchorage reinforcement with lower stress distribution in comparison with model B. The upper canines in model B present an extrusion tendency. Meanwhile, the mandibular dentition in models B and C experience undesired movement tendencies with little discrepancy from each other. CONCLUSIONS Class II elastics are generally effective for anchorage reinforcement as the upper-molar distalization is performed with clear aligners. Class II elastics attached to an aligner by precision cutting is a superior alternative for maxillary anchorage control in cases that the proclination of upper incisors and extrusion of upper canines are unwanted.
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Affiliation(s)
- Xulin Liu
- grid.233520.50000 0004 1761 4404Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Air Force Medical University, Xi’an, 710032 China
| | - Yuxun Cheng
- grid.233520.50000 0004 1761 4404Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Air Force Medical University, Xi’an, 710032 China
| | - Wen Qin
- grid.233520.50000 0004 1761 4404Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Air Force Medical University, Xi’an, 710032 China
| | - Shishu Fang
- grid.233520.50000 0004 1761 4404Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Air Force Medical University, Xi’an, 710032 China
| | - Wei Wang
- Urumql DW Innovation InfoTech Co.Ltd, Xinjiang, 830000 China
| | - Yanning Ma
- grid.263452.40000 0004 1798 4018Shanxi Medical University School and Hospital of Stomatology, Taiyuan, 030001 China
| | - Zuolin Jin
- grid.233520.50000 0004 1761 4404Department of Orthodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Air Force Medical University, Xi’an, 710032 China
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Efficacy of Er, Cr: YSGG laser phosphoric acid gel and Riboflavin activated by Photodynamic therapy on enamel reconditioning rebonded to metallic brackets: An Invitro study. Photodiagnosis Photodyn Ther 2022; 40:103043. [PMID: 35921974 DOI: 10.1016/j.pdpdt.2022.103043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 07/25/2022] [Accepted: 07/28/2022] [Indexed: 12/14/2022]
Abstract
AIM To evaluate the shear bond strength (SBS) and failure percentage of rebonded metallic brackets after employing various enamel-reconditioning methods (37% phosphoric acid, sandblasting, Er, Cr: YSGG laser, and Riboflavin (RF). MATERIAL AND METHODS After sample size calculation, a sum of 40 non-carious, non-traumatically extracted and sound human premolar teeth were collected and the enamel surface was prepped by etching, washing, and drying. The enamel surface was primed with a bonding agent and light cured, later brackets were bonded via composite. After bonding, bracket debonding was begun using a Weingart plier and the enamel surface was reconditioned before rebonding. Samples were divided into four (n=10) reconditioning groups at random and subjected to SB with 90-μm alumina particles group 1, Er, Cr: YSGG laser group 2, 37% PA (control) group 3, and RF group 4 respectively. After reconditioning, brackets were rebonded to the enamel surface via an adhesive system and composite. Later, samples were exposed to the universal testing machine for SBS analysis, and bond failure analysis was performed by using an adhesive remnant index (ARI). Statistical analysis was executed by one-way ANOVA and Post Hoc Tukey multiple comparison tests at a statistically significant level of p ˂ 0.05. RESULTS The SBS analysis showed that the highest SBS of rebounded brackets was exhibited by 37% phosphoric acid (control) and the lowest SBS by sandblasting enamel surface with 90-μm alumina particles for enamel prior rebonding. However, Er, Cr: YSGG laser and RF activated by PDT validated comparable SBS results to control (p>0.05). Contrarily, sandblasting with 90-μm alumina particles showed a statistically significant difference from other analyzed reconditioning groups (p<0.05). Deliberating failure rate analysis by ARI index, the most eminent failures predicted among groups were scored between 0 and 1 except for sandblasting which majorly resulted in a score of 2 showing cohesive type failure. CONCLUSION Chromium-doped erbium, yttrium-scandium-gallium-garnet (Er, Cr: YSGG) laser, and Riboflavin activated by photodynamic therapy have the potential to be used as an alternative to 37% phosphoric acid for enamel surface reconditioning before the rebonding metallic bracket.
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3D Finite Element Study of the Physiological Anchorage Control Concept on Anchorage Molars in Lingual Orthodontics. JOURNAL OF HEALTHCARE ENGINEERING 2022; 2022:1421586. [DOI: 10.1155/2022/1421586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/18/2022] [Accepted: 10/26/2022] [Indexed: 11/23/2022]
Abstract
Objective. To study the effect of the physiological anchorage control concept on anchorage molars in lingual and labial orthodontic techniques. Methods. Three-dimensional finite element models, including the right maxillary first molar, periodontal ligament, alveolar bone, and buccal tube, were established. The models were divided into the McLaughlin–Bennett–Trevisi (MBT™) straight-wire model with 0-degree maxillary first molar axial inclination and the physiologic anchorage Speewire system (PASS) model with −7-degree maxillary first molar axial inclination. Simulated sliding retraction forces (1 N, 1.5 N, and 2 N) were loaded on the buccal side and lingual side, and retraction forces (0.5 N, 0.75 N, and 1 N) were loaded on the buccal and lingual sides simultaneously. The displacements, principal stresses, and von Mises stresses of the periodontal ligament under different conditions were derived. Results. The anchorage molars showed different degrees of rotation, tipping, intrusion, and extrusion. As the force increased, these displacement trends also increased. The mesial displacement of the buccal + lingual force loading was less than that of the other two groups. Under the same force load method, the mesial displacement of the PASS group was less than that of the MBT group. Tilt movement increases the tensile stress of the distal cervical margin and root mesial apical third and the compressive stress of the mesial cervical margin and root distal apical third. The maximum stress of the periodontal ligament was less than that of the other two groups when the lingual force was loaded. Conclusion. The physiological anchorage control concept in lingual orthodontics provides better sagittal anchorage control than in labial orthodontics, but there is no significant difference numerically. Attention should be given to the control of torsion, torque, and arch width. Tilt movement increases the PDL stress of the cervical margin and root apical third. The sliding retraction force should be loaded lingually to maintain the force value of 1∼1.5 N.
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Singh H, Khanna M, Walia C, Khatria H, Fatima A, Kaur N. Displacement Pattern, Stress Distribution, and Archwire Play Dimensions during En-masse Retraction of Anterior Teeth using Sliding Mechanics: A FEM Study. Int J Clin Pediatr Dent 2022; 15:739-744. [PMID: 36866138 PMCID: PMC9973075 DOI: 10.5005/jp-journals-10005-2463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Aims This finite element study was undertaken to evaluate the pattern of stress distribution around the implant and anterior teeth during en-masse retraction in the premolar extraction case. Displacement of the teeth and play of wire in the bracket slot were also evaluated to determine the most favorable height of the power arm attached to the arch-wire. Materials and methods A three-dimensional (3D) finite element model of the maxilla was constructed using computed tomography (CT) scan. A total of 12 models were fabricated with different heights of power arms placed distal to the canine. A retraction force of 1.5 N was applied from the implant placed between the roots of the second premolar and first molar, and the response was predicted using Analysis of Systems (ANSYS) software. Results When power-arm height was near the center of resistance of the anterior segment, stability in the stress distribution around the implant site and anterior teeth was observed. Displacement of the teeth varied along the three planes of space with the change in power-arm height. Conclusion For en-masse retraction, power-arm height should be kept at a level of the center of resistance. Play in the bracket slot and the archwire show a negative role in the bodily movement of anterior teeth. Clinical significance For efficient en-masse retraction of anterior teeth, it is imperative to study the most effective site of application of force. Therefore, our study recommends certain key points to keep in mind during the attachment of the power arm and engaging wire in the bracket slot, which could benefit the orthodontist immensely. How to cite this article Singh H, Khanna M, Walia C, et al. Displacement Pattern, Stress Distribution, and Archwire Play Dimensions during En-masse Retraction of Anterior Teeth using Sliding Mechanics: A FEM Study. Int J Clin Pediatr Dent 2022;15(6):739-744.
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Affiliation(s)
- Harvinder Singh
- Department of Orthodontics & Dentofacial Orthopaedics, National Dental College and Hospital, Dera Bassi, Punjab, India
| | - Mannu Khanna
- Department of Orthodontics & Dentofacial Orthopaedics, Teerthanker Mahaveer Dental College & Research Centre, Teerthanker Mahaveer University, Moradabad, Uttar Pradesh, India
| | - Chanjyot Walia
- Department of Orthodontics & Dentofacial Orthopaedics, Maharishi Markandeshwar College of Dental Sciences & Research, Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala, Haryana, India
| | - Harjoy Khatria
- Department of Orthodontics & Dentofacial Orthopaedics, Maharishi Markandeshwar College of Dental Sciences & Research, Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala, Haryana, India
| | - Asiya Fatima
- Department of Orthodontics & Dentofacial Orthopaedics, Maharishi Markandeshwar College of Dental Sciences & Research, Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala, Haryana, India
| | - Navjot Kaur
- Department of Oral & Maxillofacial Surgery, Rayat Bahra Dental College and Hospital, Mohali, Punjab, India
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Wu C, Liu X, Zhang H, Zhang Q, Ding S, Jin S, Zheng X, Fu C, Han Q, Shen J, Xu J, Ye N, Jiang F, Wu T. Response of human periodontal ligament to orthodontic force using superb microvascular imaging. Am J Orthod Dentofacial Orthop 2022; 162:e257-e266. [PMID: 36089442 DOI: 10.1016/j.ajodo.2022.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 08/01/2022] [Accepted: 08/01/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Remodeling of the periodontal ligament (PDL) during orthodontic tooth movement is closely related to the vascularity of the PDL, which has not been thoroughly investigated in humans. This study aimed to measure the width and vascular parameters of human PDL using superb microvascular imaging for the first time. METHODS Patients aged 18-25 years were selected for participation. The intervention was randomly allocated from the maxillary canines to the first molars on both sides using 50 g or 150 g of force. The width and vascular parameters of the PDL were measured using superb microvascular imaging at different time intervals (baseline, 30 minutes, and 1, 3, 7, and 14 days). RESULTS Before the intervention, the width of the PDL ranged from 0.14 to 0.25 mm, and the vascular index ranged from 9.40% to 13.54%. After applying orthodontic forces, the cervical and middle PDL widths increased. The vascular index decreased slightly in 30 minutes, decreased to a minimum value after 1 day, increased to the maximum in 3-7 days, and returned to baseline values in 14 days. The values of other vascular parameters showed similar trends. CONCLUSIONS The width and vascular parameters of the PDL changed slightly after force application, underwent changes in the period of reconstruction for 3-7 days, and eventually returned to baseline in 14 days.
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Affiliation(s)
- Chuan Wu
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China
| | - Xiaoyu Liu
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China
| | - Huan Zhang
- Department of Medical Ultrasound, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Qunyan Zhang
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China
| | - Siqi Ding
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China
| | - Shiyu Jin
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China
| | - Xiuyun Zheng
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China
| | - Chunfeng Fu
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China
| | - Quancheng Han
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China
| | - Jun Shen
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China
| | - Jianguang Xu
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China
| | | | - Fan Jiang
- Department of Medical Ultrasound, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
| | - Tingting Wu
- Department of Orthodontics, School and Hospital of Stomatology, Anhui Medical University, Anhui Provincial Key Laboratory of Oral Diseases, Hefei, Anhui, China.
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Sheng C, Wang L, Huang Z, Wang T, Guo Y, Hou W, Xu L, Wang J, Yan X. Transformer-Based Deep Learning Network for Tooth Segmentation on Panoramic Radiographs. JOURNAL OF SYSTEMS SCIENCE AND COMPLEXITY 2022; 36:257-272. [PMID: 36258771 PMCID: PMC9561331 DOI: 10.1007/s11424-022-2057-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/23/2022] [Indexed: 05/28/2023]
Abstract
Panoramic radiographs can assist dentist to quickly evaluate patients' overall oral health status. The accurate detection and localization of tooth tissue on panoramic radiographs is the first step to identify pathology, and also plays a key role in an automatic diagnosis system. However, the evaluation of panoramic radiographs depends on the clinical experience and knowledge of dentist, while the interpretation of panoramic radiographs might lead misdiagnosis. Therefore, it is of great significance to use artificial intelligence to segment teeth on panoramic radiographs. In this study, SWin-Unet, the transformer-based Ushaped encoder-decoder architecture with skip-connections, is introduced to perform panoramic radiograph segmentation. To well evaluate the tooth segmentation performance of SWin-Unet, the PLAGH-BH dataset is introduced for the research purpose. The performance is evaluated by F1 score, mean intersection and Union (IoU) and Acc, Compared with U-Net, Link-Net and FPN baselines, SWin-Unet performs much better in PLAGH-BH tooth segmentation dataset. These results indicate that SWin-Unet is more feasible on panoramic radiograph segmentation, and is valuable for the potential clinical application.
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Affiliation(s)
- Chen Sheng
- Medical School of Chinese PLA, Beijing, 100853 China
- Department of Stomatology, the first Medical Centre, Chinese PLA General Hospital, Beijing, 100853 China
| | - Lin Wang
- Medical School of Chinese PLA, Beijing, 100853 China
- Department of Stomatology, the first Medical Centre, Chinese PLA General Hospital, Beijing, 100853 China
- Beihang University, Beijing, 100191 China
| | - Zhenhuan Huang
- Medical School of Chinese PLA, Beijing, 100853 China
- Department of Stomatology, the first Medical Centre, Chinese PLA General Hospital, Beijing, 100853 China
- Beihang University, Beijing, 100191 China
| | - Tian Wang
- Medical School of Chinese PLA, Beijing, 100853 China
- Department of Stomatology, the first Medical Centre, Chinese PLA General Hospital, Beijing, 100853 China
- Beihang University, Beijing, 100191 China
| | - Yalin Guo
- Medical School of Chinese PLA, Beijing, 100853 China
- Department of Stomatology, the first Medical Centre, Chinese PLA General Hospital, Beijing, 100853 China
- Beihang University, Beijing, 100191 China
| | - Wenjie Hou
- Medical School of Chinese PLA, Beijing, 100853 China
- Department of Stomatology, the first Medical Centre, Chinese PLA General Hospital, Beijing, 100853 China
- Beihang University, Beijing, 100191 China
| | - Laiqing Xu
- Medical School of Chinese PLA, Beijing, 100853 China
- Department of Stomatology, the first Medical Centre, Chinese PLA General Hospital, Beijing, 100853 China
- Beihang University, Beijing, 100191 China
| | - Jiazhu Wang
- Medical School of Chinese PLA, Beijing, 100853 China
- Department of Stomatology, the first Medical Centre, Chinese PLA General Hospital, Beijing, 100853 China
- Beihang University, Beijing, 100191 China
| | - Xue Yan
- Medical School of Chinese PLA, Beijing, 100853 China
- Department of Stomatology, the first Medical Centre, Chinese PLA General Hospital, Beijing, 100853 China
- Beihang University, Beijing, 100191 China
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Xia Q, He Y, Jia L, Wang C, Wang W, Wang C, Song J, Fan Y. Assessment of labially impacted canines traction mode with clear aligners vs. fixed appliance: A comparative study based on 3D finite element analysis. Front Bioeng Biotechnol 2022; 10:1004223. [PMID: 36277381 PMCID: PMC9579379 DOI: 10.3389/fbioe.2022.1004223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/21/2022] [Indexed: 12/05/2022] Open
Abstract
Purpose: The objective of this study was to evaluate and compare the biomechanical differences between clear aligner and fixed appliance in the traction of labially impacted canines based on 3D finite element analysis. Methods: A series of patient-oriented finite element models were constructed, including a maxillary dentition with a right labially canine, maxilla, periodontal ligaments, traction attachments, and clear aligners. The two most common clinical scenarios were investigated: Scenario A: impacted canine (distal) and Scenario B: impacted canine (mesial). For each clinical scenario, three traction models with clear aligners and one fixed appliance model were established. Results: In all four models, the impacted canines exhibited similar initial displacement tendencies of mesially rotated in Scenario A and distally rotated in Scenario B, and with small differences in periodontal ligament stress magnitude. However, the sum of the periodontal ligament stresses of the anchorage teeth in the clear aligner mode was in the range of 56.28–76.21 kPa and in the fixed appliance mode was in the range of 6.61–7.22 kPa. The maximum value of initial displacement of the anchorage teeth in the clear aligner mode was in the range of 13.71–19.72 μm, while in the fixed appliance mode was 3.10–3.92 μm. Conclusion: For impacted canines, clear aligner mode and fixed appliance mode have little difference in biomechanical effect. However, the anchorage teeth in the clear aligner mode endure higher stress and show a more pronounced displacement tendency. In addition, the biomechanical effects of different clear aligner traction models are various but not obvious.
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Affiliation(s)
- Qian Xia
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Yao He
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Lurong Jia
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Chunjuan Wang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Weixu Wang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Chao Wang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, China
- *Correspondence: Jinlin Song, ; Chao Wang,
| | - Jinlin Song
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
- *Correspondence: Jinlin Song, ; Chao Wang,
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, China
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Torqued and conventional cantilever for uprighting mesially impacted molars: A 3-dimensional finite element analysis. Am J Orthod Dentofacial Orthop 2022; 162:e203-e215. [PMID: 35999156 DOI: 10.1016/j.ajodo.2022.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 07/01/2022] [Accepted: 07/01/2022] [Indexed: 11/22/2022]
Abstract
INTRODUCTION The objective of this study was to evaluate the effects of the torqued cantilever (TC) and conventional tip-back cantilever (CC) made of stainless steel (SS) and titanium-molybdenum alloy (TMA) on the uprighting of mesially impacted mandibular molars using three-dimensional finite element analysis. METHODS The 3-dimensional mandibular model included part of the mandible with mesially tipped and impacted mandibular second molar, periodontal ligament (PDL), molar tube, mini-implant, and cantilevers. Four finite element method models (TC-SS, TC-TMA, CC-SS, and CC-TMA) were created to simulate different skeletally anchored uprighting mechanics. CC mechanics involved a known 0.019 × 0.025-in helical cantilever acting on a buccal molar tube. TC mechanics included a 0.019 × 0.025-in cantilever capable of producing mesial root torque by acting on a tube positioned on the molar disto-occlusal surface with the slot in a buccolingual direction. Three-dimensional molar displacement and stress distribution on the molar PDL were recorded. RESULTS The SS cantilever produced almost twice as much molar displacement as the TMA. TC mechanics showed more evident mesial displacement of the molar root apexes. CC mechanics had greater molar rotation. TC uprighting moment produced greater molar mesial extrusion and greater intrusion of the distal root apex. The dual deflection system of the TC mechanics induced the lowest stress on the PDL, regardless of the metallic alloy. CONCLUSIONS TC delivered a more efficient uprighting moment to the molar with less unwanted tooth movement and stress on the PDL and a more accessible site for bonding the molar tube.
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Lahoud P, Jacobs R, Boisse P, EzEldeen M, Ducret M, Richert R. Precision medicine using patient-specific modelling: state of the art and perspectives in dental practice. Clin Oral Investig 2022; 26:5117-5128. [PMID: 35687196 DOI: 10.1007/s00784-022-04572-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 05/30/2022] [Indexed: 12/25/2022]
Abstract
The dental practice has largely evolved in the last 50 years following a better understanding of the biomechanical behaviour of teeth and its supporting structures, as well as developments in the fields of imaging and biomaterials. However, many patients still encounter treatment failures; this is related to the complex nature of evaluating the biomechanical aspects of each clinical situation due to the numerous patient-specific parameters, such as occlusion and root anatomy. In parallel, the advent of cone beam computed tomography enabled researchers in the field of odontology as well as clinicians to gather and model patient data with sufficient accuracy using image processing and finite element technologies. These developments gave rise to a new precision medicine concept that proposes to individually assess anatomical and biomechanical characteristics and adapt treatment options accordingly. While this approach is already applied in maxillofacial surgery, its implementation in dentistry is still restricted. However, recent advancements in artificial intelligence make it possible to automate several parts of the laborious modelling task, bringing such user-assisted decision-support tools closer to both clinicians and researchers. Therefore, the present narrative review aimed to present and discuss the current literature investigating patient-specific modelling in dentistry, its state-of-the-art applications, and research perspectives.
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Affiliation(s)
- Pierre Lahoud
- OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU, Leuven, Belgium.,Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium.,Periodontology and Oral Microbiology, Department of Oral Health Sciences, KU Leuven, Leuven, Belgium
| | - Reinhilde Jacobs
- OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU, Leuven, Belgium.,Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium.,Department of Dental Medicine, Karolinska Institute, Stockholm, Sweden
| | - Philippe Boisse
- Laboratoire de Mécanique Des Contacts Et Structures, UMR 5259, CNRS/INSA, Villeurbanne, France
| | - Mostafa EzEldeen
- OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU, Leuven, Belgium.,Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium.,Department of Oral Health Sciences, KU Leuven and Paediatric Dentistry and Special Dental Care, University Hospitals Leuven, Leuven, Belgium
| | - Maxime Ducret
- Hospices Civils de Lyon, PAM d'Odontologie, Lyon, France.,Faculty of Odontology, Lyon 1 University, Lyon, France.,Laboratoire de Biologie Tissulaire Et Ingénierie Thérapeutique, UMR5305 CNRS/UCBL, Lyon, France
| | - Raphael Richert
- Laboratoire de Mécanique Des Contacts Et Structures, UMR 5259, CNRS/INSA, Villeurbanne, France. .,Hospices Civils de Lyon, PAM d'Odontologie, Lyon, France. .,Faculty of Odontology, Lyon 1 University, Lyon, France.
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Johal A, Bourauel C, Moghanchi S, Dickerson T, Gaudin P, Elliott EL. The Tip and Torque adjustable bracket as a new concept in design. Angle Orthod 2022; 92:380-387. [PMID: 35061018 PMCID: PMC9020388 DOI: 10.2319/061421-474.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 11/01/2021] [Indexed: 05/22/2024] Open
Abstract
OBJECTIVES To test a new concept in bracket design-the tip and torque adjustable bracket (TTAB)-to identify its integral ability to change both tip and torque. MATERIALS AND METHODS The newly designed TTAB underwent independent testing using the orthodontic measurement and simulation system. The TTAB incorporated Roth tip and torque prescription values, with the unique quality of the bracket to enhance or reduce the innate prescribed values of tip (by either +10° or -10°) and torque (by either +7.5° or -7.5°). The TTAB was tested using both the incorporated standard Roth prescription on the rate of canine retraction (sliding mechanics), using 0.018-inch stainless-steel (SS) arch wire, and with alteration of tip values (-10° and +10°). Similarly, frictional measurements and torque evaluations using 0.019 × 0.025-inch SS arch wire were undertaken with the standard prescription and altered torque (+7.5° and -7.5°). In addition, a number of control investigations were performed. Differences were analyzed using analysis of variance. RESULTS The rate of observed tooth movement for the TTAB with its prescribed baseline values was comparable to that of the control brackets. Importantly, the alteration of TTAB tip to -10° and +10° significantly (P < .001) increased and reduced, respectively, the rates of canine retraction. In the alteration of torque, at +7.5° and -7.5°, the bracket delivered a moment of +9.3 (2.8) Nmm and -11.9 (3.8) Nmm, respectively, to the lateral incisor (P < .001). CONCLUSIONS This in vitro study demonstrates a new concept in preadjusted edgewise bracket design, offering adjustable tip and torque, with the potential for expanded clinical scope.
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Liu L, Song Q, Zhou J, Kuang Q, Yan X, Zhang X, Shan Y, Li X, Long H, Lai W. The effects of aligner overtreatment on torque control and intrusion of incisors for anterior retraction with clear aligners: A finite-element study. Am J Orthod Dentofacial Orthop 2022; 162:33-41. [DOI: 10.1016/j.ajodo.2021.02.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 01/22/2023]
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Liu L, Zhan Q, Zhou J, Kuang Q, Yan X, Zhang X, Shan Y, Li X, Lai W, Long H. Effectiveness of an anterior mini-screw in achieving incisor intrusion and palatal root torque for anterior retraction with clear aligners. Angle Orthod 2021; 91:794-803. [PMID: 34061964 DOI: 10.2319/120420-982.1] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 04/01/2021] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES To analyze the biomechanical system of anterior retraction with clear aligner therapy (CAT) with and without an anterior mini-screw and elastics. MATERIALS AND METHODS Models including a maxillary dentition (without first premolars), maxilla, periodontal ligaments (PDLs), attachments, and aligners were constructed and imported to finite element software. Three model groups were created: (1) control (CAT alone), (2) labial elastics (CAT with elastics between the anterior mini-screw and buttons on central incisors), and (3) linguoincisal elastics (CAT with elastics between the anterior mini-screw and precision cuts on the lingual sides of the aligner). Elastic forces (0-300 g, in 50 g increments) were applied. RESULTS CAT alone caused lingual tipping and extrusion of the incisors. Labial elastics caused palatal root torquing and intrusion and mesial tipping of the central incisors, while linguoincisal elastics produced palatal root torquing and intrusion of both central and lateral incisors. Second premolars were intruded in all three groups, with less intrusion in the linguoincisal elastics group. For the control group, stress was concentrated on both labial and lingual root surfaces, alveolar ridge, and cervical and apical PDLs. Stress was more concentrated in the labial elastics group and less concentrated in the linguoincisal elastics group. CONCLUSIONS CAT produced lingual tipping and extrusion of incisors during anterior retraction. Anterior mini-screws and elastics can achieve incisor intrusion and palatal root torquing. Linguoincisal elastics are superior to labial elastics with a lower likelihood of buccal open bite. Root resorption and alveolar defects may occur in CAT, more likely for labial elastics and less likely for linguoincisal elastics.
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Oliveira PLE, Soares KEM, Andrade RMD, Oliveira GCD, Pithon MM, Araújo MTDS, Sant'anna EF. Stress and displacement of mini-implants and appliance in Mini-implant Assisted Rapid Palatal Expansion: analysis by finite element method. Dental Press J Orthod 2021; 26:e21203. [PMID: 34468562 PMCID: PMC8405139 DOI: 10.1590/2177-6709.26.4.e21203.oar] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/24/2020] [Indexed: 11/21/2022] Open
Abstract
Objective: In this study, simulations were performed by the finite element method (FEM) to determine the tension and displacement in mini-implants and in expander appliance during rapid maxillary expansion, by varying the number and location of the mini-implants. Methods: For the computational simulation, a three-dimensional mesh was used for the maxilla, mini-implants and expander appliance. Comparisons were made on six different Mini-implant Assisted Rapid Palatal Expander (MARPE) configurations, by varying the amount and location of mini-implants. A closed suture was design and received two activations of 0.25 mm, and an open suture had a 0.5-mm aperture that received 20 activations, also of 0.25 mm. Results: For the closed suture, the maximum displacement values in the mini-implants were between 0.253 and 0.280 mm, and stress was between 1,348.9 and 2,948.2 MPa; in the expander appliance, the displacement values were between 0.256 and 0.281 mm, and stress was between 738.52 and 1,207.6 MPa. For the open suture, the maximum displacement values in the mini-implants were between 2.57 and 2.79 mm, and stress was between 5,765.3 and 10,366 MPa; in the appliance, the maximum displacements was between 2.53 and 2.89 mm, and stress was between 4,859.7 and 9,157.4 MPa. Conclusions: There were higher stress concentrations in the mini-implant than in the expander arm. In the simulations with a configuration of three mini-implants, stress overload was observed in the isolated mini-implant. Displacements of the mini-implants and arms of the appliance were similar in all simulations.
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Affiliation(s)
- Pedro Lima Emmerich Oliveira
- Universidade Federal do Rio de Janeiro, Departamento de Ortodontia e Odontologia Pediátrica (Rio de Janeiro/RJ, Brazil)
| | | | | | | | - Matheus Melo Pithon
- Universidade Estadual do Sudoeste da Bahia, Departamento de Ortodontia e Odontologia Pediátrica (Vitória da Conquista/BA, Brazil)
| | - Mônica Tirre de Souza Araújo
- Universidade Federal do Rio de Janeiro, Departamento de Ortodontia e Odontologia Pediátrica (Rio de Janeiro/RJ, Brazil)
| | - Eduardo Franzotti Sant'anna
- Universidade Federal do Rio de Janeiro, Departamento de Ortodontia e Odontologia Pediátrica (Rio de Janeiro/RJ, Brazil)
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Ovy EG, Romanyk DL, Flores Mir C, Westover L. Modelling and evaluating periodontal ligament mechanical behaviour and properties: A scoping review of current approaches and limitations. Orthod Craniofac Res 2021; 25:199-211. [PMID: 34355507 DOI: 10.1111/ocr.12527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 11/29/2022]
Abstract
This scoping review is intended to synthesize the techniques proposed to model the tooth-periodontal ligament-bone complex (TPBC), while also evaluating the suggested periodontal ligament (PDL) material properties. It is concentrated on the recent advancements on the PDL and TPBC models, while identifying the advantages and limitations of the proposed approaches. Systematic searches were conducted up to December 2020 for articles that proposed PDL models to assess orthodontic tooth movement in Compendex, Web of Science, EMBASE, MEDLINE, PubMed, ScienceDirect, Google Scholar and Scopus databases. Although there have been many studies focused on the evaluation of PDL material properties through numerous modelling approaches, only a handful of approaches have been identified to investigate the interface properties of the PDL as a complete dynamical system (TPBC models). Past reviews on the analytical and experimental determination of the PDL properties already show a concerning range in reported output values-some nearly six orders of magnitude in difference-that strongly suggested the need for further investigation. Surprisingly, it has not yet been possible to determine a narrower range of values for the PDL material properties. Moreover, very few scientific approaches address the TPBC as an integrated complex system model. In consequence, current methods for capturing the PDL material behaviour in a clinical setting are limited and inconclusive. This synthesis encourages more systematic, pragmatic and phenomenological research in this area.
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Affiliation(s)
- Enaiyat Ghani Ovy
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Dan L Romanyk
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Carlos Flores Mir
- Department of Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Lindsey Westover
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
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Using FEM to Assess the Effect of Orthodontic Forces on Affected Periodontium. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11167183] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Orthodontic treatment in patients with no periodontal tissue breakdown vs. horizontal bone loss should be approached with caution even though it can bring significant benefits in terms of periodontal recovery and long-term success. We used the finite element method (FEM) to simulate various clinical scenarios regarding the periodontal involvement: healthy with no horizontal bone loss, moderate periodontal damage (33%) and severe horizontal bone loss (66%). Afterwards, forces of different magnitudes (0.25 N, 1 N, 3 N, and 5 N) were applied in order to observe the behavioral patterns. Through mathematical modeling, we recorded the maximum equivalent stresses (σ ech), the stresses on the direction of force application (σ c) and the displacements produced (f) in the whole tooth–periodontal ligament–alveolar bone complex with various degrees of periodontal damage. The magnitude of lingualization forces in the lower anterior teeth influences primarily the values of equivalent tension, then those of the tensions in the direction in which the force is applied, and lastly those of the displacement of the lower central incisor. However, in the case of the lower lateral incisor, it influences primarily the values of the tensions in the direction in which the force is applied, then those of equivalent tensions, and lastly those of displacement. Anatomical particularities should also be considered since they may contribute to increased periodontal risk in case of lingualization of the LLI compared to that of the LCI, with a potential emergence of the “wedge effect”. To minimize periodontal hazards, the orthodontic force applied on anterior teeth with affected periodontium should not exceed 1 N.
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Biomechanical Effect of Orthodontic Treatment of Canine Retraction by Using Metallic Orthodontic Mini-Implant (OMI) Covered with Various Angles of Revolving Cap. Appl Bionics Biomech 2021; 2021:9952392. [PMID: 34335874 PMCID: PMC8315870 DOI: 10.1155/2021/9952392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/21/2021] [Indexed: 12/01/2022] Open
Abstract
Objective This study evaluated the biomechanical effects of a metallic orthodontic mini-implant (OMI) covered with various types of angled revolving cap on the peri-OMI bone and the canine periodontal ligament (PDL) by finite element (FE) analyses. Materials and Methods Three-dimensional FE models included comprised cortical bone and cancellous bone of the maxilla, and the OMIs were created. The forces (0.98 N) pulled in both the canine hook and the revolving cap, pulling towards each other in both directions as loading conditions. The upper surface of the maxilla was fixed as a boundary condition. Results The bone stresses were increasing in the models by using OMI covered with a revolving cap as compared with that in the conventional model (in which only the OMI was placed). However, no obvious differences in bone stresses were observed among the models with various types of angled revolving cap. The minimum principal strain in the canine PDL was highest for condition 180T, followed by condition 180L. However, the maximum differences in the values between each experimental model and the conventional model were around 5%. Conclusion This study showed no obvious effects in decreasing or increasing stress/strain in bone and PDL by using various types of angled revolving cap covered metallic mini-implant in orthodontic treatment of canine retraction.
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Hirai Y, Watanabe K, Deguchi T, Ueda K, Hamada K, Tanaka E. Influence of insertion depth on stress distribution in orthodontic miniscrew and the surrounding bone by finite element analysis. Dent Mater J 2021; 40:1270-1276. [PMID: 34193725 DOI: 10.4012/dmj.2020-400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We aimed to elucidate stress distribution in miniscrews and the surrounding bone when miniscrews inserted at different depths were implanted vertically or obliquely. The distributions of the equivalent stress on the screw surface and the minimum principal stress in the surrounding bone were calculated using finite element models. When the miniscrews were inserted vertically and obliquely, screw head displacement, greatest equivalent stress on the miniscrew surface, and absolute value of minimum principal stresses in the surrounding bone decreased with increasing insertion depth. Stresses in the obliquely inserted miniscrew with upward traction were smaller than in other insertion conditions, irrespective of insertion depth. With the application of orthodontic force, stress distribution around the miniscrew and surrounding bone is closely related to the insertion depth and insertion angle, which mutually affect each other. In particular, the obliquely inserted miniscrew with upward traction might be the most secure against screw failure and fracture.
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Affiliation(s)
- Yuzo Hirai
- Department of Orthodontics and Dentofacial Orthopedics, Tokushima University Graduate School of Oral Sciences.,Department of Oral and Maxillofacial Surgery, Kobe City Nishi-Kobe Medical Center
| | - Keiichiro Watanabe
- Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School.,Division of Orthodontics, The Ohio State University College of Dentistry
| | - Toru Deguchi
- Division of Orthodontics, The Ohio State University College of Dentistry
| | | | - Kenichi Hamada
- Department of Biomaterials and Bioengineering, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Eiji Tanaka
- Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School
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Jain A, Prasantha GS, Mathew S, Sabrish S. Analysis of stress in periodontium associated with orthodontic tooth movement: a three dimensional finite element analysis. Comput Methods Biomech Biomed Engin 2021; 24:1841-1853. [PMID: 33982607 DOI: 10.1080/10255842.2021.1925255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
It is well known that the initiating factor for the biologic changes is the stress induced in the periodontal tissue; but as of now there is no gauge to measure the stress in the PDL directly. Therefore finite element model can be used to study the stress-strain relation through simulation of the PDL. The aim of the study was to simulate the stress response in the periodontium for different moment to farce ratios induced by tipping, translation, rotation, intrusion, extrusion and root torque by means of finite element method. The three-dimensional finite element model of the mandibular first molar was constructed. The pattern of Von misses stress and the maximum displacement of the mandibular molar was recorded on application of different combination of moment to force ratio. The periodontium was sensitive to changes in the load values. The stress pattern in the periodontal ligament for a lingually directed force without counterbalancing moments showed high concentration at the cervical level of the root. With addition of counter-tipping and counter-rotation moments, a relatively even distribution of stress throughout PDL was obtained. Additionally, high stress concentration was observed on the root surface at the furcation level for forces applied parallel to the long axis. Translation type of tooth movement showed relatively even distribution of the stress in the PDL and makes the tooth less susceptible to root resorption.
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Affiliation(s)
- Ankita Jain
- Department of Orthodontics, Faculty of Dental Sciences, M.S. Ramaiah University of Applied Sciences, Bangalore, India
| | - G S Prasantha
- Department of Orthodontics, Faculty of Dental Sciences, M.S. Ramaiah University of Applied Sciences, Bangalore, India
| | - Silju Mathew
- Department of Orthodontics, Faculty of Dental Sciences, M.S. Ramaiah University of Applied Sciences, Bangalore, India
| | - Sharanya Sabrish
- Department of Orthodontics, Faculty of Dental Sciences, M.S. Ramaiah University of Applied Sciences, Bangalore, India
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Khan J, Goyal M, Kumar M, Kushwah A, Kaur A, Sharma M. Comparative evaluation of displacement and stress distribution pattern during maxillary arch distalization with Infra Zygomatic Screw- A three dimensional finite element study. Int Orthod 2021; 19:291-300. [PMID: 33875363 DOI: 10.1016/j.ortho.2021.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/19/2021] [Accepted: 03/20/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVE This study aimed to evaluate and compare the distribution of stress and displacement of teeth during maxillary arch distalization with IZC (Infra zygomatic crest) screw with two maxillary positions and different lever arm heights. SETTINGS AND DESIGN Six three-dimensional finite element models of the maxillary arch were constructed with third molars extracted. Models 1, 2 and 3: IZC 6 (mesial to mesiobuccal root of first molar, 6) with 0mm, 4mm and 8mm lever arm height; Models 4, 5 and 6: IZC 7 (mesial to mesiobuccal root of second molar, 7) with 0mm, 4mm and 8mm, respectively. MATERIAL AND METHODS MBT preadjusted Brackets (slot size 0.022×0.028") were placed over the clinical crown's centre with 0.019×0.025" stainless steel archwire on all six models. Retraction force of 4N was applied with different combinations of IZC screws and lever arm bilaterally using Nickel-Titanium (NiTi) closed coil spring. Then, evaluation of stress distribution, von Mises stress and maxillary teeth displacement were performed using ANSYS 12.1 software. RESULTS In this study, maximum von Mises stress in alveolar bone (cortical bone) was observed in Model 4 (107.79MPa) at the screw fixation site that was within the optimum limit (135MPa). Different extents of displacements like labiolingual tipping of crown, labiolingual tipping of root, extrusion and intrusion were noticed. The models with 0mm and 4mm lever arm height (models1, 2, 4 and 5) showed more controlled crown and root movements in comparison to 8mm long lever arm models (models 3 and 6). In model 5, a maximum distal movement compared to all other five models was observed. CONCLUSIONS IZC 7 position showed the most favourable results (maximum distalization) with the lever arm height of 4mm. Therefore, the nearer the force to the centre of resistance of the tooth, the greater is distalization. Stresses on the IZC screw decreases when lever arm height increases, in all the models.
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Affiliation(s)
- Junaid Khan
- Department of Orthodontics and Dentofacial Orthopaedics, Teerthanker Mahaveer Dental College, Moradabad, Uttar Pradesh, India.
| | - Manish Goyal
- Department of Orthodontics and Dentofacial Orthopaedics, Teerthanker Mahaveer Dental College, Moradabad, Uttar Pradesh, India
| | - Mukesh Kumar
- Department of Orthodontics and Dentofacial Orthopaedics, Teerthanker Mahaveer Dental College, Moradabad, Uttar Pradesh, India
| | - Ashish Kushwah
- Department of Orthodontics and Dentofacial Orthopaedics, Institute of Dental Education & Advanced Studies, Gwalior, Madhya Pradesh, India
| | - Amandeep Kaur
- Department of Orthodontics and Dentofacial Orthopaedics, Teerthanker Mahaveer Dental College, Moradabad, Uttar Pradesh, India
| | - Madhur Sharma
- Department of Orthodontics and Dentofacial Orthopaedics, Teerthanker Mahaveer Dental College, Moradabad, Uttar Pradesh, India
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Sana S, Reddy R, Talapaneni AK, Hussain A, Bangi SL, Fatima A. Evaluation of stability of three different mini-implants, based on thread shape factor and numerical analysis of stress around mini-implants with different insertion angle, with relation to en-masse retraction force. Dental Press J Orthod 2021; 25:59-68. [PMID: 33503126 PMCID: PMC7869798 DOI: 10.1590/2177-6709.25.6.059-068.oar] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 02/03/2020] [Indexed: 11/22/2022] Open
Abstract
Objectives: Assess the stability of three different mini-implants, based on thread shape
factor (TSF), and evaluate stresses at the mini-implant site and surrounding
cortical bone on application of retraction force, at two different insertion
angles. Methods: Mini-implants of three different diameters (M1 - Orthoimplant, 1.8mm), (M2 -
Tomas, 1.6mm) and (M3 - Vector TAS, 1.4mm) and length of 8mm were used.
Using scanning electronic microscopy, the mean thread depth, pitch and
relationship between the two (TSF) were calculated. The mini-implants were
loaded into a synthetic bone block and the pull-out strength was tested. One
way ANOVA and Tukey post-hoc tests were used to compare the
pull-out strength of mini-implants. P values < 0.05 were considered
statistically significant. Finite element models (FEM) were constructed with
insertion angulation at 90° and 60°, with retraction force of 150 g. The
results were analyzed using ANSYS software. Results: Statistically significant difference was found among all the three
mini-implants for thread depth and pitch (< 0.001). Statistically
significant higher pull-out force value was seen for Orthoimplant. The
stress distribution level in mini-implant and surrounding bone was observed
to be smaller for Orthoimplant. Conclusion: Orthoimplant mini-implants have more favorable geometric characteristics
among the three types, and less stress with 90°angulation.
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Affiliation(s)
- Safiya Sana
- Al-Badar Rural Dental College & Hospital, Department of Orthodontics & Dentofacial Orthopaedics (Gulbarga/KA, India)
| | - Rekha Reddy
- Al-Badar Rural Dental College & Hospital, Department of Orthodontics & Dentofacial Orthopaedics (Gulbarga/KA, India)
| | - Ashok Kumar Talapaneni
- Al-Badar Rural Dental College & Hospital, Department of Orthodontics & Dentofacial Orthopaedics (Gulbarga/KA, India)
| | - Arshad Hussain
- Al-Badar Rural Dental College & Hospital, Department of Orthodontics & Dentofacial Orthopaedics (Gulbarga/KA, India)
| | - Sayeeda Laegue Bangi
- Al-Badar Rural Dental College & Hospital, Department of Orthodontics & Dentofacial Orthopaedics (Gulbarga/KA, India)
| | - Asma Fatima
- Al-Badar Rural Dental College & Hospital, Department of Orthodontics & Dentofacial Orthopaedics (Gulbarga/KA, India)
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Bachiri A, Djebbar N, Boutabout B, Serier B. Effect of different impactor designs on biomechanical behavior in the interface bone-implant: A comparative biomechanics study. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 197:105723. [PMID: 32877819 DOI: 10.1016/j.cmpb.2020.105723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVE The implant makes it possible to replace a missing tooth in a very esthetic way with a very comfortable result because the tooth is fixed and independent of its neighbors, like a natural tooth. Titanium alloy grade 5 or Ti-6AI-4V, has excellent properties mechanical and an interesting modulus of elasticity. It is known to be biocompatible and remains the material of choice for the medical sector: orthopedic, dental implants and maxillofacial surgery. The objective of this study was to analyze the influence on the biomechanical behavior of dental implants with a variable velocity at the implant/bone contact area and to compare the differences EQV stress between spherical and conical impactor. METHODS We chose a dental implant located in the lower jaw, in the region of the second premolar. The assembly consists of six parts: Feldsphatic porcelain crown, cobalt-chrome alloy framework, titanium alloy implant abutment and the jaw is composed of cancellous bone and cortical bone. The width and height of cortical bone model were 15.8 mm and 23.5 mm, respectively. The thickness of its upper part was 2 mm. The implant and its components were modeled using SolidWorks 2016 software and then exported to Abaqus program 6.13 using the finite element method. The geometry of the solid implant is presented in form of cylinder screw of length 8 mm and diameter 4.8 mm. The sizes of the abutment are: length l = 7.2 mm, lower diameter d1= 2.6 mm and great diameter d2 = 3.6 mm. RESULTS Maximum von Mises stress generated by spherical impactor are lower than those obtained by conical impactor. For big velocity of the impactor, the stresses may be critical since the mechanical properties of the implant material and the cortical and cancellous bone could not withstand stress magnitudes recorded in this analysis. CONCLUSIONS A conical projectile leads to an equivalent stress greater than that generated by a spherical projectile. Whatever the projectile shape, the stress intensity increases in the different components of the dental prosthesis with increasing the impact velocity.
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Affiliation(s)
- Abdessamed Bachiri
- Mechanical Physic Laboratory of Materials (LMPM), Department of Mechanical Engineering, University of Sidi Bel Abbes, BP 89, Ben M'hidi City, Sidi Bel Abbes 22000, Algeria
| | - Noureddine Djebbar
- Mechanical Physic Laboratory of Materials (LMPM), Department of Mechanical Engineering, University of Hassiba Benbouali, Hay Salem, N 19 National road, Chlef 02000, Algeria.
| | - Benali Boutabout
- Mechanical Physic Laboratory of Materials (LMPM), Department of Mechanical Engineering, University of Sidi Bel Abbes, BP 89, Ben M'hidi City, Sidi Bel Abbes 22000, Algeria
| | - Boualem Serier
- Mechanical Physic Laboratory of Materials (LMPM), Department of Mechanical Engineering, University of Sidi Bel Abbes, BP 89, Ben M'hidi City, Sidi Bel Abbes 22000, Algeria
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Popa A, Dehelean C, Calniceanu H, Watz C, Brad S, Sinescu C, Marcu OA, Popa CS, Avram S, Nicolov M, Szuhanek CA. A Custom-Made Orthodontic Mini-Implant-Effect of Insertion Angle and Cortical Bone Thickness on Stress Distribution with a Complex In Vitro and In Vivo Biosafety Profile. MATERIALS 2020; 13:ma13214789. [PMID: 33120951 PMCID: PMC7663474 DOI: 10.3390/ma13214789] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Orthodontic mini-implant failure is a debatable subject in clinical practice. However, the most important parameter to evaluate the success rate of mini-implant is the primary stability, which is mainly influenced by cortical bone thickness (CBT) and insertion angle. MATERIALS AND METHODS Three-dimensional finite element models of the maxilla were created and a custom-made, self-drilling, tapered mini-implant was designed. For the pull-out test, 12 simulations were performed, sequentially increasing the thickness of the cortical bone (1, 1.5 and 2 mm) and the insertion angle (30°, 60°, 90°, 120°). For the force analysis, 24 simulations were performed using an experimental orthodontic traction force of 2 N both in the horizontal and vertical axis. RESULTS Insertion angle and CBT have significant impact on force reaction values (p < 0.05). Cortical bone stress had the lowest value when the mini-implant had a 30° insertion angle and the highest value when the implant had a 120° insertion angle, while the CBT was 1 mm. Cortical bone stress had the lowest value with an insertion angle of 90° and the highest value when the implant was inserted at an angle of 30°, while the CBT was 2 mm independent of the force direction. Regarding the biosafety profile of the mini-implant alloy, the present results reveal that the custom-made mini-implant presents good biocompatibility. CONCLUSIONS When the CBT is reduced, we recommend inclined insertion while, when the CBT is appropriate, perpendicular insertion is advised.
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Affiliation(s)
- Adelina Popa
- 2nd Department of Orthodontics, Faculty of Dental Medicine, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania; (A.P.); (C.A.S.)
| | - Cristina Dehelean
- 2nd Department of Toxicology and Drug Industry, Faculty of Pharmacy, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania;
| | - Horia Calniceanu
- 1st Department/Periodontology, Faculty of Dental Medicine, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania
- Correspondence: (H.C.); (C.W.); Tel.: +40-745-322-649 (H.C.); +40-746-227-217 (C.W.)
| | - Claudia Watz
- 1st Department of Pharmaceutical Physics and Biophysics, Faculty of Pharmacy, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania;
- Correspondence: (H.C.); (C.W.); Tel.: +40-745-322-649 (H.C.); +40-746-227-217 (C.W.)
| | - Silviu Brad
- 2nd Department of Radiology, Faculty of Dental Medicine, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania;
| | - Cosmin Sinescu
- 2nd Department of Prostheses Technology and Dental Material, Faculty of Dental Medicine, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania;
| | - Olivia A. Marcu
- Dental Medicine Department, Faculty of Medicine and Pharmacy, University of Oradea, 410087 Oradea, Romania;
| | | | - Stefana Avram
- 2nd Department of Pharmacognosy, Faculty of Pharmacy, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania;
| | - Mirela Nicolov
- 1st Department of Pharmaceutical Physics and Biophysics, Faculty of Pharmacy, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania;
| | - Camelia A. Szuhanek
- 2nd Department of Orthodontics, Faculty of Dental Medicine, Victor Babes University of Medicine and Pharmacy, 300041 Timisoara, Romania; (A.P.); (C.A.S.)
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Benaissa A, Merdji A, Bendjaballah MZ, Ngan P, Mukdadi OM. Stress influence on orthodontic system components under simulated treatment loadings. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 195:105569. [PMID: 32505974 DOI: 10.1016/j.cmpb.2020.105569] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 05/15/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVE Mini-implants have been developed and effectively used by clinicians as anchorage for orthodontic tooth movement. The objective of this study was to elucidate the stress response of orthodontic forces on the periodontal system, bone tissues, mini-implant and the bracket-enamel interface. METHODS Computer tomography images of a commercially available mini-implant, an orthodontic bracket bonded to a central incisor, and jawbone section models were used to reconstruct three dimensional computer models. These models were exported and meshed in an ABAQUSⓇ finite-element package. Material properties, multi-segment interactions, boundary and loading conditions were then applied to each component. Finite-element analyses were conducted to elucidate the effect of orthodontic force on the equivalent von Mises stress response within the simulated orthodontic system. RESULTS The highest stress values in the orthodontic system were predicted at the mini-implant neck, at the interface of the cortical bone, and gradually decreased in the internal apical direction of the miniscrew. On the alveolar bone, the maximum stress values were located in the alveolar cortical bone near the cervical areas of the mini-implant, which is in line with clinical findings of area where bone loss was found post orthodontic tooth treatment. Another peak of von Mises stress response was found in the enamel bracket junction with a maximum up to 186.05 MPa. To ensure good bonding between the enamel and bracket, it is vital to select carefully the type and amount of bonding materials used in the bracket-enamel interface to assure an appropriate load distribution between the teeth and alveolar bone. The results also revealed the significance of the periodontal ligaments, acting as an intermediate cushion element, in the load transfer mechanism. CONCLUSIONS This study is sought to identify the stress response in a simulated orthodontic system to minimize the failure rate of mini-implants and bracket loss during orthodontic treatment.
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Affiliation(s)
- Ali Benaissa
- Laboratory LSTE, Faculty of Science and Technology, University of Mascara, Mascara 29000, Algeria
| | - Ali Merdji
- Department of Mechanical Engineering, Faculty of Science and Technology, University of Mascara, Mascara 29000, Algeria
| | | | - Peter Ngan
- Department of Orthodontics, West Virginia University Health Sciences Center, Morgantown, WV26506, United States
| | - Osama M Mukdadi
- Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV26506, United States.
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Prados-Privado M, Martínez-Martínez C, Gehrke SA, Prados-Frutos JC. Influence of Bone Definition and Finite Element Parameters in Bone and Dental Implants Stress: A Literature Review. BIOLOGY 2020; 9:biology9080224. [PMID: 32823884 PMCID: PMC7464638 DOI: 10.3390/biology9080224] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/11/2020] [Accepted: 08/11/2020] [Indexed: 12/21/2022]
Abstract
Bone plays an important role in dental implant treatment success. The goal of this literature review is to analyze the influence of bone definition and finite element parameters on stress in dental implants and bone in numerical studies. A search was conducted of Pubmed, Science Direct and LILACS, and two independent reviewers performed the data extraction. The quality of the selected studies was assessed using the Cochrane Handbook tool for clinical trials. Seventeen studies were included. Titanium was the most commonly-used material in dental implants. The magnitude of the applied loads varied from 15 to 300 N with a mean of 182 N. Complete osseointegration was the most common boundary condition. Evidence from this review suggests that bone is commonly defined as an isotropic material, despite being an anisotropic tissue, and that it is analyzed as a ductile material, instead of as a fragile material. In addition, and in view of the data analyzed in this review, it can be concluded that there is no standardization for conducting finite element studies in the field of dentistry. Convergence criteria are only detailed in two of the studies included in this review, although they are a key factor in obtaining accurate results in numerical studies. It is therefore necessary to implement a methodology that indicates which parameters a numerical simulation must include, as well as how the results should be analyzed.
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Affiliation(s)
- María Prados-Privado
- Asisa Dental, Research Department, C/José Abascal, 32, 28003 Madrid, Spain;
- Department of Signal Theory and Communications, Higher Polytechnic School, Universidad de Alcalá de Henares, Ctra. Madrid-Barcelona, Km. 33,600, Alcalá de Henares, 28805 Madrid, Spain
- Department Continuum Mechanics and Structural Analysis, Higher Polytechnic School, Carlos III University, Avenida de la Universidad 30, Leganés, 28911 Madrid, Spain
- IDIBO GROUP (Group of High-Performance Research, Development and Innovation in Dental Biomaterials of Rey Juan Carlos University), Avenida de Atenas s/n, Alcorcón, 28922 Madrid, Spain
- Correspondence:
| | | | - Sergio A. Gehrke
- Department of Research, Biotecnos, Cuareim 1483, Montevideo CP 11100, Uruguay;
| | - Juan Carlos Prados-Frutos
- Department of Medicine Specialties and Public Health, Faculty of Health Sciences, Rey Juan Carlos University, Avenida de Atenas s/n, Alcorcón, 28922 Madrid, Spain;
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Karimi Dastgerdi A, Rouhi G, Dehghan MM, Farzad-Mohajeri S, Barikani HR. Linear Momenta Transferred to the Dental Implant-Bone and Natural Tooth-PDL-Bone Constructs Under Impact Loading: A Comparative in-vitro and in-silico Study. Front Bioeng Biotechnol 2020; 8:544. [PMID: 32596223 PMCID: PMC7303479 DOI: 10.3389/fbioe.2020.00544] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 05/06/2020] [Indexed: 11/16/2022] Open
Abstract
During dental trauma, periodontal ligament (PDL) contributes to the stability of the tooth-PDL-bone structure. When a dental implant is inserted into the bone, the dental implant-bone construct will be more prone to mechanical damage, caused by impact loading, than the tooth-PDL-bone construct. In spite of the prevalence of such traumas, the behavioral differences between these two constructs have not been well-understood yet. The main goal of this study was to compare the momentum transferred to the tooth-PDL-bone and dental implant-bone constructs under impact loading. First, mechanical impact tests were performed on six canine mandibles of intact (N = 3) and implanted (N = 3) specimens using a custom-made drop tower apparatus, from release heights of 1, 2, and 3 cm. Next, computed tomography-based finite element models were developed for both constructs, and the transferred momenta were calculated. The experimental results indicated that, for the release heights of 1, 2, and 3 cm, the linear momenta transferred to the dental implant-bone construct were 33.1, 31.0, and 27.5% greater than those of the tooth-PDL-bone construct, respectively. Moreover, results of finite element simulations were in agreement with those of the experimental tests (error <7.5%). This work tried to elucidate the effects of impact loading on the dental implant-bone and tooth-PDL-bone constructs using both in-vitro tests and validated in-silico simulations. The findings can be employed to modify design of the current generation of dental implants, based on the lessons one can take from the biomechanical behavior of a natural tooth structure.
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Affiliation(s)
| | - Gholamreza Rouhi
- Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Mohammad Mehdi Dehghan
- Department of Surgery and Radiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
- Institute of Biomedical Research, University of Tehran, Tehran, Iran
| | | | - Hamid Reza Barikani
- Dental Implant Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
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Lee Y, Chun Y. An investigation into structural behaviors of skulls chewing food in different occlusal relationships using FEM. Clin Exp Dent Res 2020; 6:277-285. [PMID: 32558315 PMCID: PMC7301394 DOI: 10.1002/cre2.273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 11/29/2019] [Accepted: 11/29/2019] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES This study aims to investigate the effect of different occlusal relationships on skull structural and mechanical behaviors through simulation of chewing food. METHODS Finite element (FE) skull models of occlusion for Class I, end-on Class II, and full-cusp Class II were generated. End-on Class II and full-cusp Class II were chosen as mild and severe Class II occlusions, respectively. A simplified food bolus was introduced between the upper and lower dentition of the right molars. Chewing food was simulated in the skulls by moving the mandible. An experiment was conducted to measure strains at selective locations and compared them to the analytical results for validation. RESULTS In the early stages of mandibular movement, masticatory forces predicted from the skull models without food were lower than the skull models with food but increased drastically after occluding teeth full enough. As a result, the relationship between masticatory force and mandible movement shows that there is no significant difference between the skull models with food and without food in the range of human masticatory force, approximately 250 N. In all the cases of skulls including a food bolus, stress was similarly propagated from the mandible to the maxilla and concentrated in the same regions, including the mandibular notch and alveolar bone around the lower molars. CONCLUSION It is predicted that there is no significant difference of bite force-mandible movement relationships and stress distributions of skull and teeth, between end-on Class II and full-cusp Class II models. When simulating chewing activities on candy and carrot, it is also found that there is no difference of masticatory performance between Class II occlusions, from structural as well as mechanical perspectives.
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Affiliation(s)
- Yeo‐Kyeong Lee
- Architectural and Urban System Engineering, Division of Sustainable Systems Engineering, ELTEC College of EngineeringEwha Womans UniversitySeoulSouth Korea
| | - Youn‐Sic Chun
- Orthodontics & dentofacial orthopedics, School of MedicineEwha Womans UniversitySeoulSouth Korea
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Thakkar U, Patil NS, Thakkar AP, Chitko SS, Jaltare P. Study of the Stress Distribution Around the Mini-implant During Maxillary Anterior Intrusion Under Different Conditions: A 3-Dimensional Finite Element Analysis. JOURNAL OF INDIAN ORTHODONTIC SOCIETY 2020. [DOI: 10.1177/0301574219896027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Introduction: Correction of deep bite is one of the major challenges of orthodontic treatment. Mini-implants provide stable intra-oral anchorage and facilitate the maxillary incisors to be intruded without the usual side. The purpose of this finite element study was to evaluate the stress distribution around the mini-implant during maxillary anterior intrusion under different conditions of different angulations and different positions of implant. Material and Methods: Finite element analysis was carried out. Stress under the following 4 conditions was analyzed: (a) single central implant placed at 90°, (b) single central implant placed at 120°, (c) bilaterally placed implant at 90°, and (d) bilaterally placed implant at 120°. Results: The displacement seen with 90° angulation in the single implant case is less compared with the 120° angulation case for all the 6 maxillary anterior teeth. Also, in the bilateral implant case, the Von Mises stress is less when the 90° angulation case is compared to 120° angulation case. But in bilaterally placed implant, the stress gets distributed evenly in the anterior region. The stress in 90° angulation cases seems to be concentrated at the center. Conclusion: Stresses measured on the teeth are less and distributed more evenly when the point of force application is bilateral. It was also observed that the stress increases with increase in the angulation of the implant. As the contact between the implant and the bone increases, the stability increases. Hence, the implant should be obliquely inserted into the bone. Concentrated stresses are not favorable as they can increase the risk of bone and root resorption.
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Affiliation(s)
- Udita Thakkar
- Manubhai Patel Dental College and Hospital, Vadodara, Gujarat, India
| | | | | | | | - Pratik Jaltare
- Senior lecturer, Department of Orthodontics, Swargiya Dadasaheb Kalmegh Smruti Dental College and Hospital, Nagpur, Maharashtra, India
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Two distalization methods compared in a novel patient-specific finite element analysis. Am J Orthod Dentofacial Orthop 2019; 156:326-336. [PMID: 31474262 DOI: 10.1016/j.ajodo.2018.09.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 09/01/2018] [Accepted: 09/01/2018] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Orthodontic mini-implants aid in the correction of distocclusions via direct anchorage (pull from mini-implant to teeth) and indirect anchorage (teeth pulled against other teeth anchored by the mini-implant). The aim of this study was to compare stress levels on the periodontal ligament (PDL) of maxillary buccal teeth in direct and indirect distalization against orthodontic mini-implants and accounting for individual variation in maxillary anatomy and biomechanical characteristics of the compact bone. METHODS A 3D model of the maxilla containing the different components (teeth, PDL, trabecular and cortical bones) was generated from a computed tomographic scan. Cortical bone was divided into several areas according to previously defined zones. Bone stiffness and thickness data, obtained from 11 and 12 cadavers, respectively, were incorporated into the initial model to simulate the individual cortical bone variation at the different locations. Subsequently, a finite element analysis was used to simulate the distalization modalities. RESULTS Stresses at the buccal, palatal, mesial, and distal surfaces were significantly different between adjacent teeth under stiffness but not thickness variation. In both distalization modalities, low or no significant correlations were found between stress values and corresponding cortical bone thicknesses. High significant and inverted correlations were observed at the first molar between stress amounts and cortical bone stiffness (direct modality: -0.68 < r < -0.72; indirect modality: -0.80 < r < -0.82; P <0.05). CONCLUSIONS With the use of a novel finite element approach that integrated human data on variations in bone properties, findings suggested that cortical bone stiffness may influence tooth movement more than bone thickness. Significant clinical implications could be related to these findings.
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López Gualdrón CI, Bravo Ibarra ER, Murillo Bohórquez AP, Garnica Bohórquez I. Present and future for technologies to develop patient-specific medical devices: a systematic review approach. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2019; 12:253-273. [PMID: 31496840 PMCID: PMC6689557 DOI: 10.2147/mder.s215947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 07/08/2019] [Indexed: 01/25/2023] Open
Abstract
The main purpose of this investigation was to systematically review the literature regarding case studies on patient-specific implants and devices, with the goal of analyzing the process of developing custom-made medical devices. A content analysis was performed to identify design processes and methodologies implemented to develop devices such as implants adapted to bone geometries. Reverse engineering, computer-aided design, simulation of assets, and rapid prototyping technologies were selected according to their interoperability in a process framework for developing new products. Finally, results from the case studies and process stages identified in the consulted research were analyzed. These results showed a relationship between the scope and complexity of the process and the stage of technology integration of the patient-specific device development. The analyzed case studies were characterized by technical, scientific, and multidisciplinary components to achieve research goals. Likewise, integration of technologies using patient-specific technologies is needed for product development that converges into designing devices, such as implants, biomodels, and cutting drilling guides.
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Affiliation(s)
| | - Edna-Rocío Bravo Ibarra
- Industrial and Business Studies School, Universidad Industrial de Santander, Bucaramanga, Colombia
| | | | - Israel Garnica Bohórquez
- Industrial and Business Studies School, Universidad Industrial de Santander, Bucaramanga, Colombia
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Zhou X, Gan Y, Zhao Q, Xiong J, Xia Z. Simulation of orthodontic force of archwire applied to full dentition using virtual bracket displacement method. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3189. [PMID: 30790479 DOI: 10.1002/cnm.3189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 10/31/2018] [Accepted: 02/16/2019] [Indexed: 06/09/2023]
Abstract
OBJECTIVE Orthodontic force simulation of tooth provides important guidance for clinical orthodontic treatment. However, previous studies did not involve the simulation of orthodontic force of archwire applied to full dentition. This study aimed to develop a method to simulate orthodontic force of tooth produced by loading a continuous archwire to full dentition using finite element method. METHOD A three-dimensional tooth-periodontal ligament-bone complex model of mandible was reconstructed from computed tomography images, and models of brackets and archwire were built. The simulation was completed through two steps. First, node displacements of archwire before and after loading were estimated through moving virtual brackets to drive archwire deformation. Second, the obtained node displacements were loaded to implement the loading of archwire, and orthodontic force was calculated. An orthodontic force tester (OFT) was used to measure orthodontic force in vitro for the validation. RESULTS After the simulation convergence, archwire was successfully loaded to brackets, and orthodontic force of teeth was obtained. Compared with the measured orthodontic force using the OFT, the absolute difference of the simulation results ranged from 0.5 to 22.7 cN for force component and ranged from 2.2 to 80.0 cN•mm for moment component, respectively. The relative difference of the simulation results ranged from 2.5% to 11.0% for force component, and ranged from 0.6% to 14.7% for moment component, respectively. CONCLUSIONS The developed orthodontic force simulation method based on virtual bracket displacement can be used to simulate orthodontic force provided by the archwire applied to full dentition.
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Affiliation(s)
- Xinwen Zhou
- Department of Automation, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Yangzhou Gan
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, People's Republic of China
- CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Shenzhen, 518055, People's Republic of China
| | - Qunfei Zhao
- Department of Automation, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Jing Xiong
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, People's Republic of China
| | - Zeyang Xia
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, People's Republic of China
- CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Shenzhen, 518055, People's Republic of China
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Three-dimensional finite element analysis to evaluate biomechanical effects of different alveolar decortication approaches on rate of canine retraction. Int Orthod 2019; 17:216-226. [PMID: 31000446 DOI: 10.1016/j.ortho.2019.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION The aim of this study was to compare different corticotomy approaches and determine their biomechanical effects on rate of canine displacement when compared to conventional orthodontics. METHOD Three-dimensional Finite Element Models with conventional non-corticotomy approach (model 1) and three corticotomy approaches ensuing buccal and palatal vertical cuts (model 2), interseptal bone reduction (model 3), buccal vertical cuts (model 4) were fabricated. Displacement of the canine and von Mises stresses in the canine and trabecular bone were calculated and compared under a distal retraction force of 1.5N. RESULTS The maximum displacement of canine with minimum anchorage loss was seen in model 3 followed by model 2, model 4 and model 1. The maximum equivalent (von Mises) stress was concentrated mainly on the distal side of canine in model 3 and had a uniform distribution of stresses on entire root surface. CONCLUSIONS Corticotomy approaches effectively accelerated maxillary canine retraction, exhibiting twice the rate of canine movement with minimum anchorage loss when compared to non-corticotomy approach. Corticotomy with interseptal bone reduction was most effective in terms of canine displacement and stress distribution.
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Bonab MF, Mojra A, Shirazi M. A numerical-experimental study on thermal evaluation of orthodontic tooth movement during initial phase of treatment. J Therm Biol 2019; 80:45-55. [PMID: 30784487 DOI: 10.1016/j.jtherbio.2019.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 01/02/2019] [Accepted: 01/06/2019] [Indexed: 10/27/2022]
Abstract
The most desired target of orthodontic treatment is tooth movement as a result of application of efficient force system. In this study, effect of tooth loading is studied on temperature profile around the tooth at early stages of treatment. The basis of temperature variation is increase of cell number and activities in periodontium as a result of compression and tension of this layer. Highest cellular activities occur in the beginning of loading procedure and aim to reduce mechanical stress in the periodontium which finally ends up with orthodontic tooth movement during couple of years. To find out the correlation between temperature variation and the applied force, in vivo experiments are conducted on ten rats and temperature is measured in specific time periods. It is observed that temperature is higher in direction of the net force about 0.3℃. Next, numerical finite element analysis is carried out on the rat tooth model. Mechanical stress results show that regions with compressive stress have rather high temperature in the experiments. Mechanical stress on periodontium-bone interface is multiplied by a coefficient to simulate cellular activities on this boundary as a heat source and thermal analysis is carried out to obtain temperature profile. The thermo-mechanical coefficient is identified for each rat by imposing the experimental temperatures on numerical outputs. For assessment of a treatment efficiency and deduction of the applied force, temperatures could be measured experimentally and compared with the corresponding numerical analysis temperature result obtained by employing the thermo-mechanical coefficient found earlier for each rat.
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Affiliation(s)
- M Fakhimi Bonab
- Department of Mechanical Engineering, K. N. Toosi University of Technology, 15 Pardis St., Tehran 1991943344, Iran.
| | - A Mojra
- Department of Mechanical Engineering, K. N. Toosi University of Technology, 15 Pardis St., Tehran 1991943344, Iran.
| | - M Shirazi
- Department of Orthodontics and Dental Research Centre, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
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Wang S, Sun J, Yu YY. [Influence of three-wall osseous defects on periodontal ligament stress with three-dimensional finite element analysis]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2019; 37:42-47. [PMID: 30854817 DOI: 10.7518/hxkq.2019.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVE This study aims to explore the influence of three-wall osseous defects on periodontal ligament stress under normal occlusal forces. METHODS A finite element model for mandibular total dentition, periodontal ligament and alveolar bone was created based on cone beam computed tomography (CBCT) DICOM images. Mesial or distal proximal three-wall osseous defects at varying depths (namely, 1/3, 2/3 and 3/3 of the root) were simulated by modifying the elastic modulus of elements within the defects area. Occlusal forces with an angle of 45° to the long axis of the tooth were applied to the finite element model. In addition, the equivalent stresses of the periodontal ligament were analysed. RESULTS In the case of no bone defect, the mean value of the periodontal ligament equivalent stress of 14 teeth was 5.71 MPa. The equivalent stresses of the periodontal ligament at different depths (namely, 1/3, 2/3 and 3/3 of the root) were 6.61, 7.14 and 7.42 MPa, respectively. With increasing depth of the osseous defects, stress on the periodontal ligament increased considerably, and the initial stress increment was greater than that of a later stage. Periodontal ligament stresses with mesial proximal three-wall osseous defects (at depths of 1/3, 2/3 and 3/3 of the root) were 6.62, 7.19 and 7.51 MPa respectively. Periodontal ligament stresses with distal proximal three-wall osseous defects (at depths of 1/3, 2/3 and 3/3 of the root) were 6.60, 7.10 and 7.33 MPa, respectively. For three-wall osseous defects located in the mesial surface and distal surface, a significant difference in periodontal ligament stress was lacking. In the case of the same absorption depth, the size relationship of periodontal ligament stress was in the following order: premolars>molars>incisors>canines. CONCLUSIONS Shallow three-wall osseous defects will likely cause a notable loss in strength of the periodontal ligament. Therefore, teeth with three-wall osseous defects should become the focus of clinical research. Treatment for these teeth should be administered as early as possible.
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Affiliation(s)
- Shuang Wang
- Dept. of Periodontics, Dalian Stomatological Hospital, Dalian 116021, China
| | - Jiang Sun
- Dept. of Periodontics, Dalian Stomatological Hospital, Dalian 116021, China
| | - Yan-Yun Yu
- Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116023, China
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