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Dong L, Huang W, Wu H, Yu S, Zheng Y, Zhang Q, Ren D, Wu W, Yan X, Lv T, Yuan X. Evaluating stress and displacement in the craniomandibular complex using Twin Block appliances at varied angles: A finite element study. J Mech Behav Biomed Mater 2024; 156:106603. [PMID: 38815434 DOI: 10.1016/j.jmbbm.2024.106603] [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: 02/22/2024] [Revised: 05/07/2024] [Accepted: 05/25/2024] [Indexed: 06/01/2024]
Abstract
OBJECTIVES The objective of this investigation was to assess the stress and displacement pattern of the craniomandibular complex by employing finite element methodology to simulate diverse angulations of inclined planes that are incorporated in the Twin Block appliance. METHODS A 3D finite element representation was established by use of Cone Beam Computed Tomography (CBCT) scans. This comprehensive structure included craniofacial skeletal components, the articular disc, a posterior disc elastic layer, dental elements, periodontal ligaments, and a Twin Block appliance. This investigation is the first to incorporated inclined planes featuring three distinct angulations (45, 60, and 70°) as the study models. Mechanical impacts were evaluated within the glenoid fossa, tooth, condylar, and articular disc regions. RESULTS In all simulations, the stress generated by the Twin Block appliance was distributed across teeth and periodontal ligament, facilitating the anterior movement of mandibular teeth and the posterior displacement of maxillary teeth. Within the temporomandibular joint region, compressive forces on the superior and posterior facets of the condyle diminished, coinciding with the stress configuration that fosters condylar and mandibular growth. Stress dispersion homogenized in the condylar anterior facet and articular disc, with considerable tensile stress in the glenoid fossa's posterior aspect conforming to stress distribution that promote fossa reconfiguration. The 70° inclined plane exerts the highest force on the tissues. The condyle's maximum and minimum principal stresses are 0.36 MPa and -0.15 MPa, respectively, while those of the glenoid fossa are 0.54 MPa and -0.23 MPa. CONCLUSION Three angled appliances serve the purpose of advancing the mandible. A 45° inclined plane relative to the occlusal plane exerts balanced anteroposterior and vertical forces on the mandibular arch. Steeper angles yield greater horizontal forces, which may enhance forward growth and efficient repositioning.
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Affiliation(s)
- Lirong Dong
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China; School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Wenli Huang
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China; School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Haoting Wu
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China; School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Shaoyang Yu
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China; School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Yao Zheng
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China; School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Qiang Zhang
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China; School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - DaPeng Ren
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China; School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Wei Wu
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China; School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Xiao Yan
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China; School of Stomatology, Qingdao University, Qingdao, 266023, China
| | - Tao Lv
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, Jinan, China.
| | - Xiao Yuan
- Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China; School of Stomatology, Qingdao University, Qingdao, 266023, China.
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Murali S, Kannan A, Kailasam V. Cervical spine changes with functional appliance treatment: A systematic review and meta-analysis. J Oral Biol Craniofac Res 2024; 14:446-454. [PMID: 38855038 PMCID: PMC11157267 DOI: 10.1016/j.jobcr.2024.05.015] [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] [Received: 01/22/2024] [Revised: 04/24/2024] [Accepted: 05/18/2024] [Indexed: 06/11/2024] Open
Abstract
Objective Cervical spine posture is related to craniofacial morphology, airway, gait and body posture. This posture may be influenced by the changes in the mandibular position brought about by functional appliance therapy. Therefore, this systematic review aimed to assess the changes in the cervical spine posture with functional appliance treatment in Skeletal Class II subjects. Methods A search of studies in six electronic databases - Medline (via Pubmed), the Cochrane Library, OVID, LILACS, Scopus and Web of Science were performed until January 18, 2024 without any restriction in date or language of publication. Eligibility screening, study selection, and data extraction were performed by two reviewers independently. The risk of bias assessment of the included studies was performed with the Newcastle Ottawa scale and Cochrane RoB 2.0. Meta-analysis was performed using random effects model for assessment of changes in the cervical spine with removable and fixed functional appliances. Results Twelve articles that satisfied the eligibility criteria were included for systematic review and nine articles for meta-analysis. Five studies showed a low risk of bias, one as moderate and six as high risk of bias. GRADE assessment revealed a low quality evidence. Meta-analysis revealed a decrease of the upper cervical inclination by 1.16° (95 % CI of -2.68 to 0.35, I2 = 6 %), an increase of the middle cervical inclination by 2.20° (95 % CI of 0.46-3.94, I2 = 49 %), an increase in cervical curvature angle by 1.60° (95 % CI of 0.12-3.09, I2 = 89 %) and a decrease in cervical lordosis angle by 1.54° (95 % CI of -4.16 to 1.08, I2 = 0 %). Conclusions Minimal uprighting of the cervical spine was noted with functional appliances. Fixed functional appliances exerted a greater effect than removable functional appliances. Cervical hyperlordosis was reduced with removable functional appliance treatment. Though these changes are minimal, the clinical orthodontist should be aware that functional therapy also influences cervical spine posture. Due to the heterogeneity and low quality of evidence, the results are to be considered critically.
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Affiliation(s)
- Sandhya Murali
- Department of Orthodontics and Dentofacial Orthopedics, Sri Ramachandra Dental College & Hospital, Sri Ramachandra Institute of Higher Education and Research (DU), Porur, Chennai, 600116, India
| | - Annapurna Kannan
- Department of Orthodontics and Dentofacial Orthopedics, Sri Ramachandra Dental College & Hospital, Sri Ramachandra Institute of Higher Education and Research (DU), Porur, Chennai, 600116, India
| | - Vignesh Kailasam
- Department of Orthodontics and Dentofacial Orthopedics, Sri Ramachandra Dental College & Hospital, Sri Ramachandra Institute of Higher Education and Research (DU), Porur, Chennai, 600116, India
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Madian AM, Elfouly D. Cephalometric changes in pharyngeal airway dimensions after functional treatment with twin block versus myobrace appliances in developing skeletal class II patients: a randomized clinical trial. BMC Oral Health 2023; 23:998. [PMID: 38093237 PMCID: PMC10720117 DOI: 10.1186/s12903-023-03701-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND Several appliances have been used for correction of developing skeletal Class II, including different myofunctional appliances as Twin block (TB)as well as the new pre-fabricated Myobrace (MB) appliance. However, the effects of these devices on the pharyngeal airways have not been compared in the literature. Thus, the aim of this study was to compare the effects of two Class II correction appliances; TB and MB on the sagittal pharyngeal airway dimension (SPAD), including the nasopharyngeal airway area (NPAA), the oropharyngeal airway area (OPAA), and the laryngopharyngeal airway area (LPAA). METHODS This is a two parallel arms randomized comparative clinical trial. Twenty-six children of 9-12 years with Skeletal Class II malocclusion due to mandibular deficiency and normal maxillary growth as confirmed by lateral cephalometric X-ray readings (ANB angle > 4° and SNB angle < 78) and Cervical vertebral maturational index (CVMI) 1 or 2 were randomly assigned into two equal groups. Group I: TB, Group II: MB (prefabricated functional appliance, Myofunctional Research Co., Australia). Lateral cephalograms were taken for all patients in both groups before treatment (T1) and after treatment (6 months later) (T2). The primary aim was to assess pre and post treatment changes in the SPAD in each group, and compare between the two study groups. The secondary aim was to evaluate the sagittal skeletal measurements such as the SNA, SNB, ANB, Wits appraisal, as well as vertical skeletal measurements represented by the Frankfurt-mandibular plane angle (FMA) measured pre- and post-treatment. The independent samples t-test was used to compare the two study groups, and the mean difference and 95% confidence intervals (CI) were computed. The paired samples t-test was used to compare various parameters between T1 and T2 within each group. The cutoff for significance was p-value < 0.05. Data were analyzed using IBM SPSS for Windows (Version 26.0). RESULTS By Comparing changes in airway measurements within each group, it was found that NPAA, OPAA, and LPAA increased significantly after treatment within each group of MB and TB. TB group showed significantly higher mean difference (T2-T1) in both NPAA and OPAA than MB group with 28.39 (± 56.75) and 40.46 (± 52.16) respectively. The increase in LPAA values was not statistically significant at (T2-T1) between both groups. Regarding skeletal changes, there was a significant increase in the SNB values between T1 and T2 within each group with 2.82 (± 3.32) for MB group and 3.79 (± 3.06) for TB group Moreover, there was a significant decrease in the ANB values between T1 and T2 within each group by 2.42 (± 2.70) for MB group and 3.06 (± 1.14) for TB group. Similarly, there was a significant decrease in the ANB values between T1 and T2 within each group by -2.13 (± 0.62) for MB group and - 2.46 (± 0.72) for TB group. No significant differences were found between both groups in SNA, SNB, ANB and Wits appraisal at p = 0.06, p = 0.45, p = 0.43 and p = 0.22 respectively. FMA did not show significant difference between T1 and T2 within each group, nor showed a significant mean difference between both groups at T2-T1. CONCLUSIONS TB was more effective than MB in improving the upper (NPAA) and middle (OPAA) airways, while no difference was found regarding the lower airway (LPAA). Both TB and MB reduced the severity of developing skeletal class II due to mandibular retrognathism by forward posturing of the mandible. Thus, patients with airway problems would benefit more from TB than MB.
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Affiliation(s)
- Ahmed M Madian
- Department of Orthodontics, Faculty of Dentistry, Alexandria University, Champollion St., P.O. Box 21521, Azarita, Alexandria, Egypt
| | - Dina Elfouly
- Department of Orthodontics, Faculty of Dentistry, Alexandria University, Champollion St., P.O. Box 21521, Azarita, Alexandria, Egypt.
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Shen Y, Li X, Feng X, Yu L, Weng L, Zhang C, Shang Y, Lin J. Differences in the effects of orthodontic treatment on airway-craniocervical functional environment in adult and adolescent patients with skeletal class II high-angle: a retrospective pilot study. BMC Oral Health 2023; 23:605. [PMID: 37644470 PMCID: PMC10464110 DOI: 10.1186/s12903-023-03328-w] [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: 04/10/2023] [Accepted: 08/18/2023] [Indexed: 08/31/2023] Open
Abstract
INTRODUCTION This retrospective cohort study aimed to compare the change in upper airway and craniocervical posture after orthodontic treatment between adolescent and adult patients with Class II high-angle malocclusion. METHODS A total of 12 adolescent (mean ± standard deviation age = 13.0 ± 2.0 years) and 12 adult patients with Class II high-angle malocclusion (mean ± standard deviation age = 23.7 ± 6.4 years) were selected in this study. The lateral cephalograms and cone beam computed tomography images of adolescent and adult patients were taken before and after treatment, which can be employed to evaluate the variables of craniofacial morphology, upper airway, and craniocervical posture through paired t tests, respectively. An independent sample t test was performed to observe the differences between two groups after orthodontic intervention. For adults and adolescents, the correlation between craniofacial morphology, upper airway, and craniocervical posture was determined through Pearson correlation analysis. RESULTS In all subjects, the improvements in vertical and sagittal facial morphology after treatment were observed. Anterior and inferior movements of the hyoid bone, an increase of upper airway dimension, posterior tipping of the head and a reduction of cervical inclination in the lower and middle segments post-treatment were identified in adolescence (P < 0.05). Adults displayed anterior movements of the hyoid bone, whereas no significant difference was observed in upper airway dimension and craniocervical posture (P < 0.05). Notable differences were identified in the change of hyoid position and airway volume between two groups (P > 0.05). Mandibular plane inclination, growth pattern, occlusal plane inclination, and chin position were all significantly correlated with craniocervical posture in adolescent patients. Besides, the mandibular growth pattern and chin position in adult patients were significantly correlated with craniocervical posture (P < 0.05). CONCLUSIONS Orthodontic treatment is capable of enhancing the facial profile of patients with skeletal class II high-angle while improving their upper airway morphology and craniocervical posture, where adolescents and adults differ substantially in that the former exhibit a more favorable alteration in the airway-craniocervical functional environment.
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Affiliation(s)
- Yiyang Shen
- Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, Zhejiang, China
| | - Xin Li
- Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, Zhejiang, China
| | - Xiaoyan Feng
- Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, Zhejiang, China
| | - Lan Yu
- The Affiliated Lihuili Hospital, Ningbo University, Ningbo, Zhejiang, China
| | - Luxi Weng
- Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, Zhejiang, China
| | - Chenxing Zhang
- Department of Stomatology, Hangzhou Geriatric Hospital, Hangzhou, Zhejiang, China
| | - Yufeng Shang
- Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, Zhejiang, China
| | - Jun Lin
- Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
- Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, Zhejiang, China.
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