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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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Zou Y, Lin H, Cai J, Xie Q, Chen W, Lu YG, Xu L. Effects of functional mandibular lateral shift on craniofacial growth and development in growing rats. J Oral Rehabil 2022; 49:915-923. [PMID: 35583904 DOI: 10.1111/joor.13341] [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: 08/04/2021] [Revised: 03/29/2022] [Accepted: 05/09/2022] [Indexed: 11/26/2022]
Abstract
BACKGROUND Unilateral posterior crossbite, one of the most frequent malocclusions, is often associated with functional lateral shift of the mandible. Although the effects of functional lateral shift on the mandible and temporomandibular joint have been examined in various animal experiments, cranial and maxillary changes have received less attention. OBJECTIVE This study investigated the effects of functional lateral shift on the craniofacial complex in growing rats. METHODS Eighty 5-week-old male Sprague-Dawley rats were randomly. divided into an experimental group (n=40), which received an oblique guide appliance that shifted the mandible to the left during closure, and a control group (n=40). The rats were scanned by cone-beam computed tomography at 3 days and 1, 2, 4, and 8 weeks. The dimensions of the mandibular bone, condyle, maxilla and cranium were measured. RESULTS The mandibles of rats in the experimental group were smaller than those of the rats in the control group and were asymmetrical. The condyles of the rats in the experimental group were thinner than those of the control rats. The condylar length on the ipsilateral side was shorter and wider than that on the contralateral side from 4 to 8 weeks. No significant differences in cranial length or height were observed between the experimental and control groups. The height of the upper first molar and alveolar bone on the contralateral side was significantly smaller than that on the ipsilateral side and in the controls from 4 to 8 weeks. CONCLUSION Functional shift in the mandible produces morphological asymmetries in the mandible and maxillary region and may cause bilateral condylar degenerative changes.
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Affiliation(s)
- Yuchun Zou
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, China.,Orthodontics Department, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, 350001, China
| | - Hanyu Lin
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, China.,Orthodontics Department, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, 350001, China
| | - Jingwen Cai
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, China.,Orthodontics Department, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, 350001, China.,Institute of Stomatology & Research Center of Dental and Craniofacial Implants, School and Hospital of Stomatology, Fujian Medical University, China
| | - Qingqi Xie
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, China.,Orthodontics Department, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, 350001, China
| | - Weijia Chen
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, China.,Orthodontics Department, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, 350001, China
| | - You-Guang Lu
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, China.,Department of Preventive Dentistry, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, 350001, China
| | - Linyu Xu
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, China.,Orthodontics Department, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, 350001, China
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Lyros I, Ferdianakis E, Halazonetis D, Lykogeorgos T, Alexiou A, Alexiou KE, Georgaki M, Vardas E, Yfanti Z, Tsolakis AI. Three-Dimensional Analysis of Posterior Mandibular Displacement in Rats. Vet Sci 2022; 9:vetsci9030144. [PMID: 35324872 PMCID: PMC8953185 DOI: 10.3390/vetsci9030144] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 03/15/2022] [Accepted: 03/18/2022] [Indexed: 12/16/2022] Open
Abstract
Mandibular protrusion and its treatment is challenging for the orthodontist. The aim of the present research was to identify macroscopic changes in the mandible, based on three-dimensional Cone Beam Computed Tomography analysis. Seventy-two male Wistar rats were divided into two equal groups, experimental (group A) and control (group B). Each consisted of three equal subgroups of 12 rats (A1, A2, A3, B1, B2, B3). Full-cast orthodontic intraoral devices were attached to the maxillary incisors of the experimental animals, and effected functional posterior mandibular displacement. Throughout the experimental period, all animals were fed with mashed food. Animals were sacrificed at 30 days (A1, B1), 60 days (A2, B2) and 90 days (A3, B3). At the 60th day of the experiment, the orthodontic devices were removed from the remaining experimental subgroup A3. Measurements revealed significant differences in the anteroposterior dimensions between experimental and control subgroups. However, the observed changes in the vertical dimensions, Condylion/Go’–Menton and the Intercondylar distance proved insignificant. Posterior mandibular displacement of the mandible in growing rats affects the morphology of the mandible and culminates in the development of a smaller mandible at a grown age.
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Affiliation(s)
- Ioannis Lyros
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (E.F.); (D.H.); (A.A.); (A.I.T.)
- Correspondence:
| | - Efstratios Ferdianakis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (E.F.); (D.H.); (A.A.); (A.I.T.)
| | - Demetrios Halazonetis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (E.F.); (D.H.); (A.A.); (A.I.T.)
| | | | - Antigoni Alexiou
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (E.F.); (D.H.); (A.A.); (A.I.T.)
| | - Konstantina-Eleni Alexiou
- Department of Oral Diagnosis & Radiology, School of Dentistry, National and Kapodistrian University of Athens, 10679 Athens, Greece; (K.-E.A.); (Z.Y.)
| | - Maria Georgaki
- Department of Oral Medicine & Pathology and Hospital Dentistry, School of Dentistry, National and Kapodistrian University of Athens, 10679 Athens, Greece; (M.G.); (E.V.)
| | - Emmanouil Vardas
- Department of Oral Medicine & Pathology and Hospital Dentistry, School of Dentistry, National and Kapodistrian University of Athens, 10679 Athens, Greece; (M.G.); (E.V.)
| | - Zafeiroula Yfanti
- Department of Oral Diagnosis & Radiology, School of Dentistry, National and Kapodistrian University of Athens, 10679 Athens, Greece; (K.-E.A.); (Z.Y.)
| | - Apostolos I. Tsolakis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (E.F.); (D.H.); (A.A.); (A.I.T.)
- Department of Orthodontics, Case Western Reserve University, Cleveland, OH 44106, USA
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Lyros I, Makrygiannakis MA, Lykogeorgos T, Ferdianakis E, Tsolakis AI. Posterior Mandibular Displacement-A Systematic Review Based on Animal Studies. Animals (Basel) 2021; 11:ani11030823. [PMID: 33804016 PMCID: PMC8000001 DOI: 10.3390/ani11030823] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/04/2021] [Accepted: 03/12/2021] [Indexed: 12/31/2022] Open
Abstract
Treating extreme mandibular growth is challenging. The mandible is pushed backwards to address itsprotrusion. Nevertheless, conclusions after such displacement in animals have been contradictory. The aim of the present review is to present measurable alterations of the mandible and the condyle following retractionin healthy rats or rabbits. PubMed, Scopus and Web of Science were accessed for relevant studies up to October 2020. Eligibility was determined by the PICOS process, while the risk of bias was estimated with SYRCLE's risk of bias tool. Retraction resulted in a more distal molar occlusion and the condyle rested more posteriorly. Mandibular anteroposterior bilateral growth restriction was achieved, the condylar process measured smaller and its angulation increased. The condylar neck thickened, its posterior surface flattened, the coronoid process was measured longer, and enlarged retromolar density was registered. Differences in the ramus height and the intercondylar distance were insignificant. Changes persisted for the period of study and subsequently the mandible resumed its inherited growth pattern. The timing of mandibular shaping and TMJ outcomes might depend on the properties of the applied force. Stability is of concern and well-structured, long-term studies are expected to resolve the issue and further clarify the results of posterior mandibular displacement.
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Affiliation(s)
- Ioannis Lyros
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (M.A.M.); (E.F.); (A.I.T.)
- Correspondence:
| | - Miltiadis A. Makrygiannakis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (M.A.M.); (E.F.); (A.I.T.)
| | - Theodoros Lykogeorgos
- Paediatric Dentist, “Hatzikosta” General Hospital of Messolonghi, 30200 Messolonghi, Greece;
| | - Efstratios Ferdianakis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (M.A.M.); (E.F.); (A.I.T.)
| | - Apostolos I. Tsolakis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (M.A.M.); (E.F.); (A.I.T.)
- Department of Orthodontics, Case Western Reserve University, Cleveland, OH 44106, USA
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Zoller G, Hahn H, Di Girolamo N. Technological Advances in Diagnostic Imaging in Exotic Pet Medicine. Vet Clin North Am Exot Anim Pract 2019; 22:397-417. [PMID: 31395322 DOI: 10.1016/j.cvex.2019.05.002] [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] [Indexed: 12/21/2022]
Abstract
Diagnostic imaging relies on interpretation of interactions between the body tissue and various energies, such as x-rays, ultrasound, and magnetic or nuclear energies, to differentiate normal from abnormal tissues. Major technological improvements regarding emission and detection of the energetic waves, as well as reconstruction and interpretation of the images, have occurred. These advances made possible visualization of smaller structures, quantitative evaluation of functional processes, and development of unique imaging-guided procedures. This article reviews the technological advances that allowed development of cone beam computed tomography, dual-energy x-ray absorptiometry, and contrast-enhanced ultrasonography, which all could have applications in exotic pet medicine.
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Affiliation(s)
- Graham Zoller
- Exotic Pet Department, Centre Hospitalier Vétérinaire Frégis, 43 Avenue Aristide Briand, Arcueil 94110, France.
| | - Harriet Hahn
- Diagnostic Imaging Department, Centre Hospitalier Vétérinaire Frégis, 43 Avenue Aristide Briand, Arcueil 94110, France
| | - Nicola Di Girolamo
- Tai Wai Small Animal and Exotic Hospital, 69-75 Chik Shun Street, Tai Wai, Sha Tin, New Territories, Hong Kong
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The influence of altered occlusion on pro-inflammatory cytokine levels in the TMJ synovial tissues of rats. Arch Oral Biol 2014; 59:1164-71. [PMID: 25103542 DOI: 10.1016/j.archoralbio.2014.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 06/17/2014] [Accepted: 07/13/2014] [Indexed: 11/20/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate whether altered occlusion affects both the condylar cartilage thickness and the cytokine levels of the TMJs of rats. DESIGN Thirty adult-male rats (n=30) were randomly assigned to three experimental conditions: a control group that underwent sham operations with unaltered occlusion; an FPDM group that underwent functional posterior displacement of the mandible that was induced by an incisor guiding appliance; and an iOVD group in which the increased occlusal vertical dimension was induced in the molars. The rats were subjected to the FPDM or iOVD model for 14 days and then killed. Both the right and left TMJs were removed and randomly assigned to examination with staining or immunoassay techniques. Toluidine blue staining was used to measure the thicknesses of the four layers of the articular cartilage (i.e., the fibrous, proliferating, mature, and hypertrophic layers). ELISA assays were used to assess the concentrations of the pro-inflammatory cytokines IL-1α, IL-1β, IL-6, and tumour necrosis factor (TNF-α). The measurements of the articular cartilage layers and cytokine concentrations were analyzed with ANOVA and Tukey's tests and Kruskal-Wallis and Dunn tests, respectively (α=5%). RESULTS The thickness of articular cartilage in the FPDM group (0.3±0.03mm) was significantly greater than those of the control (0.2±0.01mm) and iOVD (0.25±0.03mm) groups. No significant difference was observed between the control and iOVD groups. The four articular cartilage layers were thicker in the FPDM group than in the control and iOVD groups, and the latter two groups did not differ one from each other. Both the FPDM and iOVD groups exhibited higher cytokine levels than did the control (p<0.05) group. Compared to the FPDM group, the iOVD group exhibited significantly higher levels of IL-1β and TNF-α. CONCLUSION Both models induced inflammation in the TMJ and caused significant structural changes in the TMJ and surrounding tissues.
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