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Gross A, Buschang PH, Shakya A, Jing Y. Short-term effects of mechanical loading on the transdifferentiation of condylar chondrocytes. Am J Orthod Dentofacial Orthop 2023; 164:201-214. [PMID: 36922241 PMCID: PMC10659147 DOI: 10.1016/j.ajodo.2022.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 12/01/2022] [Accepted: 12/01/2022] [Indexed: 03/14/2023]
Abstract
INTRODUCTION Transdifferentiation of chondrocytes into bone cells explains most of the prenatal and early postnatal condylar growth, but its role during later postnatal growth and the mechanisms regulating transdifferentiation remain unknown. This study aimed to quantify the effects of mechanical loading on chondrocyte-derived osteogenesis during late postnatal condylar growth using a short-term mandibular laterotrusion model. METHODS Thirty 4-week-old Aggrecan-CreERT2, R26RtdTomato, and 2.3Col1a1-GFP compound mice received tamoxifen injections and were divided into control and experimental groups. Appliances were bonded to shift the mandibles of the experimental mice for 5 days, causing protrusion and retrusion of the right and left condyles, respectively. Radiographic, microcomputed tomographic, and histomorphometric analyses were performed. RESULTS The experimental and control groups showed substantial transdifferentiation of chondrocytes into bone cells. The experimental mice developed asymmetric mandibles, with the protrusive side significantly longer than the retrusive side. The protrusive condyles showed significantly increased chondrogenesis and greater numbers of chondrocyte-derived osteogenic cells, especially in the posterior third. The opposite effects were seen on the retrusive side. CONCLUSIONS Transdifferentiation of chondrocytes into bone cells occurs during late postnatal condylar growth. Laterotrusion regulates condylar chondrogenesis and chondrocyte transdifferentiation, which alters the amount and direction of condylar growth. Our study demonstrated that chondrocytes are key players in condylar bone formation and should be the focus of studies to control and further understand condylar growth.
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Affiliation(s)
- Amanda Gross
- Department of Orthodontics, Texas A&M University School of Dentistry, Dallas, Tex
| | - Peter H Buschang
- Department of Orthodontics, Texas A&M University School of Dentistry, Dallas, Tex
| | - Ajay Shakya
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, Dallas, Tex
| | - Yan Jing
- Department of Orthodontics, Texas A&M University School of Dentistry, Dallas, Tex.
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Guan H, Yonemitsu I, Ikeda Y, Ono T. Reversible Effects of Functional Mandibular Lateral Shift on Masticatory Muscles in Growing Rats. Biomedicines 2023; 11:2126. [PMID: 37626623 PMCID: PMC10452155 DOI: 10.3390/biomedicines11082126] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 07/22/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
In this study, we aimed to determine the effects of functional mandibular lateral shift (FMLS) on the muscle mass, fiber size, myosin heavy chain fiber type, and related gene expression in masticatory muscles (masseter and temporalis), as well as whether the baseline levels could be recovered after FMLS correction in growing rats. The FMLS appliance was placed to shift the mandible leftward by approximately 2 mm. After FMLS placement for 2 and 4 weeks, the muscles on the left side had significantly lower wet weight, mean cross-sectional area, and proportion of type IIa fibers than those on the right side or in the control groups (p < 0.05), with downregulation and upregulation of IGF-1 and GDF-8 gene expression, respectively (p < 0.05). Following 2 weeks devoted to recovery from FMLS, the muscle parameters in the recovery group were not significantly different to those of the control group, and IGF-1 expression in the left-side muscles was enhanced and GDF-8 expression was simultaneously suppressed. These findings indicate that the masticatory muscle changes induced via FMLS tend to revert to normal conditions if the intervention is eliminated at an early stage. Therefore, appropriate orthodontic treatment for FMLS during the growth period is advisable to prevent asymmetric alterations in masticatory muscles.
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Affiliation(s)
| | - Ikuo Yonemitsu
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo 113-8549, Japan
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De Carli E, Lagou A, Kiliaridis S, Denes BJ. Mandibular condyle changes in rats with unilateral masticatory function. Orthod Craniofac Res 2023; 26:37-45. [PMID: 35347850 PMCID: PMC10084257 DOI: 10.1111/ocr.12575] [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: 02/06/2022] [Revised: 03/20/2022] [Accepted: 03/24/2022] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Certain malocclusions or unilateral tooth loss can lead to asymmetric functional load of the two mandibular sides during mastication and induce skeletal asymmetries to the condylar process of growing individuals. However, in adults, asymmetric function may have a different impact. The aim of the present study was to investigate three-dimensionally the effects of unilateral masticatory function on the condylar process morphology in growing and adult rats and the adaptive processes to differential condylar loading. MATERIALS AND METHODS Fifty-six growing and adult Wistar rats aged 4 and 26 weeks respectively were obtained. The maxillary right molars of the experimental animals were extracted and all animals were followed for 12 weeks. Three-dimensional images were obtained by an in-vivo microcomputed tomography (micro-CT) examination. The following measurements were studied: condylar process height, condylar base width, and condylar cross-sectional surface. RESULTS While no differences were found with regards to condylar process height and base width, the cross-section of the condyle on the extraction side did not increase during growth in the young rats. No such differences were found in adults. Young rats had statistically significantly shorter condylar height, base width and cross-sectional surface than the adult rats and showed significant growth of these structures during the experimental period. CONCLUSION Condylar height and base width growth are not hindered by reduced occlusal function, contrary to the average cross-sectional surface, which implies that the condyle form of growing individuals becomes thinner while maintaining its length, in the absence of occlusal stimuli. The condyle of adult rats with extractions is less affected by occlusion changes.
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Affiliation(s)
- Enrico De Carli
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Aikaterini Lagou
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Stavros Kiliaridis
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Department of Orthodontics and Dentofacial Orthopedics, Dental School/Medical Faculty, University of Bern, Bern, Switzerland
| | - Balazs J Denes
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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Analysis of the Volumetric Asymmetry of the Mandibular Condyles Using CBCT. Int Dent J 2022; 72:797-804. [PMID: 35931561 PMCID: PMC9676531 DOI: 10.1016/j.identj.2022.06.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/21/2022] [Accepted: 06/24/2022] [Indexed: 12/04/2022] Open
Abstract
Objectives The aim of this study was to analyse volumetric asymmetries between the right and left condyles in relation to age, gender, and dental status. Materials and methods A retrospective analysis of 150 cone beam computed tomography (CBCT) scans was conducted. A single investigator performed the volumetric analysis of the CBCT scans using Vesalius 3D software. The volumetric data were analysed in relation to the gender, age, and dental status. Results The mean right condylar volume was significantly higher (P < .01) than the left condylar volume. Right and left condylar volumes were significantly higher (P < .01) in male study participants when compared to female study participants. There was no significant difference (P = .47) in the volumetric asymmetry between the male and female study participants. The volumetric asymmetry was significantly higher (P < .01) in the older age groups when compared to the younger age groups. The volumetric asymmetry was significantly higher (P < .01) in the partially and completely edentulous patients when compared to the dentate study participants. The condylar volume on the side having a partially edentulous area was significantly lower than the condylar volume of the contralateral dentate side (P < .001). Conclusions The volumetric asymmetry between the right and left condyle significantly increases with age and edentulousness. The result of the study encourages the clinicians to perform volumetric evaluation of the condyles in cases of radiographically evident condylar asymmetries to obtain a more accurate diagnosis.
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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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Zou Y, Cai S, Lin H, Cai J, Zheng DL, Lu YG, Xu L. Experimental functional shift-induced osteoarthritis-like changes at the TMJ and altered integrin expression in a rat model. Ann N Y Acad Sci 2022; 1511:210-227. [PMID: 35188225 DOI: 10.1111/nyas.14741] [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: 07/09/2021] [Accepted: 12/01/2021] [Indexed: 12/13/2022]
Abstract
Mandibular deviation affects the biomechanical environment of the temporomandibular joint (TMJ) and causes thinning of cartilage on the deviated side. We aimed to evaluate, using a rat model, the effect of mandibular functional deviation on the TMJ in relation to the functional roles of integrin β family members. The effects of experimental functional deviation on the TMJ of 6-week-old Sprague-Dawley female rats, randomly assigned to control (n = 42) and experimental groups (n = 42), were evaluated at 3 days and 1, 2, 4, and 8 weeks by histological staining, immunofluorescence, real-time quantitative polymerase chain reaction, and micro-computed tomography. The results showed that the experimental functional shift changed the shape of condyles, thinned the cartilage, and increased the proportion of the hypertrophic layer on the deviated sides of condyles. In addition, the extracellular matrix of the condyle cartilage exhibited degradation at 1 week and subchondral trabecular bone was lost at 4 and 8 weeks. Osteoarthritis (OA)-like changes occurred in the left and right condyles of rats in the experimental group and were aggravated over time. Integrin β family expression, especially integrin β2 , was altered from week 1, possibly related to the OA-like changes. These data may provide insight into the onset of TMJ OA.
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Affiliation(s)
- Yuchun Zou
- Fujian Key Laboratory of Oral Diseases, School of Stomatology, Fujian Medical University, Fuzhou, China.,Orthodontics Department, Research Center of Dental Esthetics and Biomechanics, Fujian Medical University, Fuzhou, China
| | - Senxin Cai
- Fujian Key Laboratory of Oral Diseases, School of Stomatology, Fujian Medical University, Fuzhou, China.,Orthodontics Department, Research Center of Dental Esthetics and Biomechanics, Fujian Medical University, Fuzhou, China
| | - Hanyu Lin
- Fujian Key Laboratory of Oral Diseases, School of Stomatology, Fujian Medical University, Fuzhou, China.,Orthodontics Department, Research Center of Dental Esthetics and Biomechanics, Fujian Medical University, Fuzhou, China
| | - Jingwen Cai
- Fujian Key Laboratory of Oral Diseases, School of Stomatology, Fujian Medical University, Fuzhou, China.,Orthodontics Department, Research Center of Dental Esthetics and Biomechanics, Fujian Medical University, Fuzhou, China
| | - Da-Li Zheng
- Fujian Key Laboratory of Oral Diseases, School of Stomatology, Fujian Medical University, Fuzhou, China
| | - You-Guang Lu
- Fujian Key Laboratory of Oral Diseases, School of Stomatology, Fujian Medical University, Fuzhou, China.,Department of Preventive Dentistry, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Linyu Xu
- Fujian Key Laboratory of Oral Diseases, School of Stomatology, Fujian Medical University, Fuzhou, China.,Orthodontics Department, Research Center of Dental Esthetics and Biomechanics, Fujian Medical University, Fuzhou, China
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Stojić V, Glišić B, Djukić L, Prokić B, Janović A, Stamenković Z, Milutinović-Smiljanić S, Danilović V, Brković B, Roganović J. Mandibular lateral deviation induces alteration in vascular endothelial growth factor expression and oxidative stress/nitric oxide generation in rat condyle, synovial membrane and masseter muscle. Arch Oral Biol 2019; 110:104599. [PMID: 31734543 DOI: 10.1016/j.archoralbio.2019.104599] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/25/2019] [Accepted: 10/30/2019] [Indexed: 11/17/2022]
Abstract
OBJECTIVE We aimed to investigate alteration in cellular signaling mediated by vascular endothelial growth factor (VEGF) and parameters of oxidative stress/nitric oxide generation, superoxide dismutase (SOD) and neuronal nitric oxide synthase (nNOS), underlying altered functional mechanical loading of TMJ (temporomandibular joint) during lateral mandibular deviation. DESIGN Thirty-eight 5-week-old male Wistar rats were divided into experimental group, which received acrylic resin appliance that shifted mandible to the left during closure, and control group. Computed tomography and histomorphometry were used for condyle analyses, while samples of condyle, synovial membrane and m. masseter were analyzed with enzyme-linked immunosorbent assay and spectrophotometry to determine VEGF and nNOS protein concentrations, and SOD activity. RESULTS Experimental group of rats developed smaller and asymmetrical mandibles. Less of new bone and cartilage formation and larger bone marrow cavities area were found in the experimental group. Higher VEGF expression in condyle and m. masseter as well as higher nNOS expression in m. masseter and synovial membrane were found in the experimental compared to the control group. Alteration of SOD activity was found in m. masseter and synovial membrane in the experimental group. CONCLUSIONS Lateral mandibular deviation induces mandibular and condylar morphological changes as well as significant cellular signaling alterations in condyle, synovial membrane and masticatory muscle. Cellular VEGF protein overexpression and oxidative stress/nitric oxide disbalance could be the mechanisms underlying unbalanced functional TMJ loading due to mandibular deviation.
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Affiliation(s)
- Vanja Stojić
- Department of Orthodontics, School of Dental Medicine, University of Belgrade, Belgrade, Serbia
| | - Branislav Glišić
- Department of Orthodontics, School of Dental Medicine, University of Belgrade, Belgrade, Serbia
| | - Ljiljana Djukić
- Department of Pharmacology in Dentistry, School of Dental Medicine, University of Belgrade, Belgrade, Serbia
| | - Bogomir Prokić
- Department for Surgery, Orthopedics and Ophtalmology, Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Serbia
| | - Aleksa Janović
- Department of Diagnostic Radiology, School of Dental Medicine, University of Belgrade, Belgrade, Serbia
| | - Zorana Stamenković
- Department of Orthodontics, School of Dental Medicine, University of Belgrade, Belgrade, Serbia
| | | | - Vesna Danilović
- Department of Histology, School of Dental Medicine, University of Belgrade, Belgrade, Serbia
| | - Božidar Brković
- Department of Oral surgery, School of Dental Medicine, University of Belgrade, Belgrade, Serbia
| | - Jelena Roganović
- Department of Pharmacology in Dentistry, School of Dental Medicine, University of Belgrade, Belgrade, Serbia.
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Morohoshi T, Ishii T, Ishikawa M, Choi D, Ariizumi D, Morikawa T, Sueishi K. Micro-CT Analysis of Morphological Changes in Mandibles of Growing Rats with Unilateral Occlusal Elevation. Open Dent J 2019. [DOI: 10.2174/1874210601913010150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Objectives:
This study investigated the effect of unilateral occlusal elevation in the molar region on facial and mandibular development in growing rats.
Materials and Methods:
Thirty 5-week-old male Wistar rats were randomly allocated to three groups (n = 10). The control group was allowed to develop naturally until 9 weeks of age. A device fitted on the caused unilateral occlusal elevation at 5 weeks in the removal group. The device was removed at 7 weeks and the rats were observed until 9 weeks. In the continuation group, the same device fitted on the left-side molars caused unilateral occlusal elevation continuously for 9 weeks. All groups underwent craniofacial scanning with three-dimensional micro-computed tomography at 5, 7, and 9 weeks.
Results:
In the removal and continuation groups, the mandible was displaced to the unelevated side. At 7 weeks, both these groups showed greater skeletal growth and molar extrusion on the elevated side, with significant differences between the elevated and unelevated sides. At 9 weeks, there were significant differences in both skeletal and alveolar growth between these groups; the asymmetry ameliorated in the removal group.
Limitations:
We evaluated three-dimensional morphometry by fitting a device to rat molars for a short observation period; thus, future studies are warranted to acquire data following long-term observation.
Conclusion:
Unilateral occlusal elevation during the growth period suppressed molar eruption and extrusion on the elevated and unelevated sides, respectively. The height of the mandibular ramus increased on the elevated side, resulting in asymmetric growth.
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Thiesen G, Freitas MPM, Araújo EA, Gribel BF, Kim KB. Three-dimensional evaluation of craniofacial characteristics related to mandibular asymmetries in skeletal Class I patients. Am J Orthod Dentofacial Orthop 2018; 154:91-98. [PMID: 29957327 DOI: 10.1016/j.ajodo.2017.10.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 10/01/2017] [Accepted: 10/01/2017] [Indexed: 02/09/2023]
Abstract
INTRODUCTION Our objective was to analyze the characteristics that affect skeletal Class I adults with mandibular asymmetries using cone-beam computerized tomography. METHODS The sample included cone-beam computerized tomography images of 120 subjects. Asymmetry was determined by the deviation of gnathion from the midsagittal plane and classified as relative symmetry, moderate asymmetry, or severe asymmetry. Maxillary and mandibular measurements were made, and the differences between the contralateral side and the deviated side were evaluated, as well as the differences between the categories of asymmetry. RESULTS For patients with moderate asymmetry, there were significant differences between the contralateral and deviated sides for some measuments in the transverse and vertical planes. For those with severe asymmetry, statistically significant differences were found between the sides for all measurements, except for the measuments that evaluated the position of the mandibular condyle in the transverse and sagittal directions. Furthermore, a strong correlation was found in patients with severe asymmetry, between the deviation of the mandibular dental midline and the lateral displacement of gnathion. CONCLUSIONS Patients with relative symmetry had a bilateral balance, whereas those with moderate and severe asymmetries showed several skeletal imbalances. A great deviation of the mandibular dental midline may indicate severe skeletal asymmetry in Class I adults.
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Affiliation(s)
- Guilherme Thiesen
- Department of Orthodontics, Saint Louis University, St Louis, Mo; Department of Orthodontics, Universidade do Sul de Santa Catarina, Florianopolis, Santa Catarina, Brazil.
| | | | | | - Bruno Frazão Gribel
- Private practice, Belo Horizonte, MG, Brazil; Department of Orthodontics, University of Michigan, Ann Arbor
| | - Ki Beom Kim
- Department of Orthodontics, Saint Louis University, St Louis, Mo
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Kim HJ, Park KM, Tak HJ, Choi JW, Kang SH, Park W, Bertin H, Corre P, Lee SH. Skeletal unit construction of rat mandible based on the masticatory muscle anatomy and double microcomputed tomography. Anat Histol Embryol 2018; 47:417-427. [PMID: 29943437 DOI: 10.1111/ahe.12374] [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: 01/10/2018] [Revised: 04/28/2018] [Accepted: 05/31/2018] [Indexed: 11/26/2022]
Abstract
This study aimed to divide the mandible into skeletal units based on three-dimensional (3D) muscular anatomy with microcomputed tomography (micro-CT) of Sprague-Dawley rat. Five normal rats were micro-CT scanned at 12 weeks of age before and after contrast enhancements for the masticatory muscles. Three-dimensional reconstruction of the mandible was performed from the initial micro-CT images, followed by segmentation of the masticatory muscles using the second enhanced micro-CT data. Bone and muscle models were superimposed based on the teeth and bony structures to evaluate muscular orientation and attachment. The mandible was divided into skeletal units using the bony structures and muscle attachments. The mandibular foramen and mental foramen were adopted as the reference points based on their anatomical and developmental significance. The skeletal units consisted of the condylar, coronoid, angular, body and symphyseal units. Further evaluation of these units in relation to development, growth, and other biology and medicine will be helpful in elucidating their biological identities.
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Affiliation(s)
- Hak-Jin Kim
- Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, Seoul, Korea
| | - Kyeong-Mee Park
- Department of Advanced General Dentistry, College of Dentistry, Yonsei University, Seoul, Korea
| | - Hye-Jin Tak
- Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea
| | - Ji Wook Choi
- Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, Seoul, Korea
| | - Sang-Hoon Kang
- Department of Oral and Maxillofacial Surgery, National Health Insurance Service, Ilsan Hospital, Goyang-si, Korea
| | - Wonse Park
- Department of Advanced General Dentistry, College of Dentistry, Yonsei University, Seoul, Korea
| | - Helios Bertin
- Stomatology and Maxillo-facial Surgery Unit, Nantes University Hospital, Nantes Cedex 1, France
| | - Pierre Corre
- Stomatology and Maxillo-facial Surgery Unit, Nantes University Hospital, Nantes Cedex 1, France
| | - Sang-Hwy Lee
- Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, Seoul, Korea.,Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea
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11
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Volumetric Analysis of 700 Mandibular Condyles Based Upon Cone Beam Computed Tomography. J Craniofac Surg 2018; 29:506-509. [DOI: 10.1097/scs.0000000000004136] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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12
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Three-dimensional growth pattern of the rat mandible revealed by periodic live micro-computed tomography. Arch Oral Biol 2018; 87:94-101. [DOI: 10.1016/j.archoralbio.2017.12.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/11/2017] [Accepted: 12/13/2017] [Indexed: 11/24/2022]
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Sugawara Y, Ishihara Y, Takano-Yamamoto T, Yamashiro T, Kamioka H. Orthodontic treatment of a patient with unilateral orofacial muscle dysfunction: The efficacy of myofunctional therapy on the treatment outcome. Am J Orthod Dentofacial Orthop 2017; 150:167-80. [PMID: 27364218 DOI: 10.1016/j.ajodo.2015.08.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Revised: 08/01/2015] [Accepted: 08/01/2015] [Indexed: 10/21/2022]
Abstract
The orofacial muscle is an important factor in the harmony of the occlusion, and its dysfunction significantly influences a patient's occlusion after craniofacial growth and development. In this case report, we describe the successful orthodontic treatment of a patient with unilateral orofacial muscle dysfunction. A boy, 10 years 0 months of age, with a chief complaint of anterior open bite, was diagnosed with a Class III malocclusion with facial musculoskeletal asymmetry. His maxillomandibular relationships were unstable, and he was unable to lift the right corner of his mouth upon smiling because of weak right orofacial muscles. A satisfactory occlusion and a balanced smile were achieved after orthodontic treatment combined with orofacial myofunctional therapy, including muscle exercises. An acceptable occlusion and facial proportion were maintained after a 2-year retention period. These results suggest that orthodontic treatment with orofacial myofunctional therapy is an effective option for a patient with orofacial muscle dysfunction.
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Affiliation(s)
- Yasuyo Sugawara
- Senior assistant professor, Department of Orthodontics, Okayama University Hospital, Okayama, Japan.
| | - Yoshihito Ishihara
- Assistant professor, Department of Orthodontics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Teruko Takano-Yamamoto
- Professor and chair, Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Japan
| | - Takashi Yamashiro
- Professor and chair, Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Osaka University, Suita, Japan
| | - Hiroshi Kamioka
- Professor and chair, Department of Orthodontics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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Goto TK, Nishida S, Yahagi M, Langenbach GEJ, Nakamura Y, Tokumori K, Sakai S, Yabuuchi H, Yoshiura K. Size and Orientation of Masticatory Muscles in Patients with Mandibular Laterognathism. J Dent Res 2016; 85:552-6. [PMID: 16723654 DOI: 10.1177/154405910608500614] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Size measurements of jaw muscles reflect their force capabilities and correlate with facial morphology. Using MRI, we examined the size and orientation of jaw muscles in patients with mandibular laterognathism in comparison with a control group. We hypothesized that the muscles of the deviated side would be smaller than those of the non-deviated side, and that the muscles of both sides would be smaller than in controls. In patients, a comparison of deviated and non-deviated sides showed, in orientation, differences for masseter and medial pterygoid muscles, but, in size, differences only for the masseter muscle. Nevertheless, muscle sizes in patients were much smaller than in controls. Lateral displacement of the mandible can explain the orientation differences, but not the smaller muscle size, in patients. It is possible that the laterodeviation initiates an adaptive process in the entire jaw system, resulting in extensive atrophy of the jaw muscles.
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Affiliation(s)
- T K Goto
- Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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16
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Abbassy MA, Watari I, Bakry AS, Ono T, Hassan AH. Calcitonin and vitamin D3 have high therapeutic potential for improving diabetic mandibular growth. Int J Oral Sci 2016; 8:39-44. [PMID: 27025264 PMCID: PMC4822182 DOI: 10.1038/ijos.2015.47] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2015] [Indexed: 11/25/2022] Open
Abstract
The goal of this study was to assess the effect of the intermittent combination of an antiresorptive agent (calcitonin) and an anabolic agent (vitamin D3) on treating the detrimental effects of Type 1 diabetes mellitus (DM) on mandibular bone formation and growth. Forty 3-week-old male Wistar rats were divided into four groups: the control group (normal rats), the control C+D group (normal rats injected with calcitonin and vitamin D3), the diabetic C+D group (diabetic rats injected with calcitonin and vitamin D3) and the diabetic group (uncontrolled diabetic rats). An experimental DM condition was induced in the male Wistar rats in the diabetic and diabetic C+D groups using a single dose of 60 mg·kg−1 body weight of streptozotocin. Calcitonin and vitamin D3 were simultaneously injected in the rats of the control C+D and diabetic C+D groups. All rats were killed after 4 weeks, and the right mandibles were evaluated by micro-computed tomography and histomorphometric analysis. Diabetic rats showed a significant deterioration in bone quality and bone formation (diabetic group). By contrast, with the injection of calcitonin and vitamin D3, both bone parameters and bone formation significantly improved (diabetic C+D group) (P < 0.05). These findings suggest that these two hormones might potentially improve various bone properties.
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Affiliation(s)
- Mona A Abbassy
- Orthodontic Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.,Alexandria University, Alexandria, Egypt
| | - Ippei Watari
- Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ahmed S Bakry
- Conservative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.,Cariology and Operative Dentistry Department, Graduate School of Medical and Dental Sciences, Tokyo Medical & Dental University, Tokyo, Japan.,Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - Takashi Ono
- Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ali H Hassan
- Orthodontic Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
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17
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Inoue K, Nakano H, Sumida T, Yamada T, Otawa N, Fukuda N, Nakajima Y, Kumamaru W, Mishima K, Kouchi M, Takahashi I, Mori Y. A novel measurement method for the morphology of the mandibular ramus using homologous modelling. Dentomaxillofac Radiol 2015; 44:20150062. [PMID: 26143939 DOI: 10.1259/dmfr.20150062] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES It is important to assess the mandibular morphology when orthognathic surgery, especially mandibular ramus osteotomy, is performed. Several studies on three-dimensional (3D) facial asymmetry have reported differences in linear and angle measurements between the deviated and contralateral sides in asymmetric mandibles. However, methods used in these studies cannot analyse the 3D morphology of the ramus. In this study, we aimed to evaluate the differences in mandibular ramus between the deviated and contralateral sides in asymmetric mandibles using traditional measurements as well as 3D shape analysis. METHODS 15 Japanese females with jaw deformities treated by orthodontic surgery were enrolled. 3D CT images were reconstructed, and 14 landmarks were identified on the model surface. Ten linear and four angle measurements were calculated using these landmarks. Homologous ramus models were constructed for each sample, and after converting all homologous models to the right side, 30 homologous models of the ramus were analysed using principal component analysis. RESULTS Firstly, eight principal components explained >80% of the total variance. Differences between the deviated and contralateral sides in measurements and scores of the eight principal components were tested. Significant difference at the 5% level between the deviated and contralateral sides was observed in five linear measurements, three angle measurements and the third principal component. The variance of the deviated side was significantly larger in the diameter between the mandibular notch and coronoid process, horizontal dilated angle of the mandibular ramus and vertical dilated angle of the mandibular ramus. The variance of the contralateral side was significantly larger in the height of mandibular ramus, height of posterior of mandibular ramus, condylar width, height of condylar head and mandibular angle. The squared multiple correlation coefficient adjusted for the degrees of freedom was 0.815. The third principal component showed the difference between the deviated and contralateral sides. Shape variation represented by the third principal component visually indicated that the contralateral side was larger and had inwardly directed coronoid process and the deviated side had a mandibular angle that was turned inwards to a greater extent. CONCLUSIONS In conclusion, we successfully created a homologous model of the mandibular ramus and demonstrated the effectiveness of this model in the 3D comparison of the ramus morphology between the contralateral and deviated sides in asymmetric mandibles.
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Affiliation(s)
- K Inoue
- 1 Section of Oral and Maxillofacial Surgery, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - H Nakano
- 1 Section of Oral and Maxillofacial Surgery, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - T Sumida
- 1 Section of Oral and Maxillofacial Surgery, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - T Yamada
- 1 Section of Oral and Maxillofacial Surgery, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - N Otawa
- 1 Section of Oral and Maxillofacial Surgery, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - N Fukuda
- 1 Section of Oral and Maxillofacial Surgery, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Y Nakajima
- 1 Section of Oral and Maxillofacial Surgery, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - W Kumamaru
- 1 Section of Oral and Maxillofacial Surgery, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - K Mishima
- 2 Department of Oral and Maxillofacial Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - M Kouchi
- 3 Digital Human Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - I Takahashi
- 4 Section of Orthodontics and Dentofacial Orthopedics, Graduate School of Dental Sciences, Kyushu University, Fukuoka, Japan
| | - Y Mori
- 1 Section of Oral and Maxillofacial Surgery, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
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An Animal Model for Inducing Deviation of the Mandible. J Oral Maxillofac Surg 2015; 73:2207-18. [PMID: 25891655 DOI: 10.1016/j.joms.2015.03.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/05/2015] [Accepted: 03/21/2015] [Indexed: 11/21/2022]
Abstract
PURPOSE Altering the occlusal surface is still a common choice for inducing a deviated mandible in an animal model. Botulinum neurotoxin type A (BoTx/A) can block the action potential transmission in neuromuscular junctions by inhibiting acetylcholine release without damaging the nerves and muscle structures. Our present study was aimed at developing an easy-to-reproduce animal model of asymmetric mandibles in which injection of BoTx/A was applied. MATERIALS AND METHODS A total of 96 healthy 4-week-old male Sprague-Dawley rats were divided into 2 groups: an experimental group (n = 48) with BoTx/A injection and a control group (n = 48) with sterile saline injection at 4 sites of the right masseter muscle. Twelve rats from each group were humanely euthanized at weeks 1, 2, 3, and 4 for morphometric analysis using the micro-computed tomography (CT) findings. RESULTS The micro-CT scans revealed facial asymmetry in the experimental group, with no facial asymmetry in the control group after injection. Significant differences were found between the experimental and control groups regarding the indexes containing the mandibular length (length from condyle to menton, length from coronoid to menton, and length of mandibular corpus from gonion to menton) and ramus height (posterior border and middle region near coronoid, and height of anterior mandible at vertical distance from menton). CONCLUSION Our data have indicated that this deviated mandible animal model induced by injection of BoTx/A is highly reproducible and might be proved suitable for future studies of the asymmetric mandible.
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Investigation of microstructure of bone tissue in mandibles of newborn rats after maternal treatment with antiretroviral drugs. Biocybern Biomed Eng 2015. [DOI: 10.1016/j.bbe.2014.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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Henderson SE, Lowe JR, Tudares MA, Gold MS, Almarza AJ. Temporomandibular joint fibrocartilage degeneration from unilateral dental splints. Arch Oral Biol 2014; 60:1-11. [PMID: 25247778 DOI: 10.1016/j.archoralbio.2014.08.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 08/15/2014] [Accepted: 08/30/2014] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The objective of this study was to determine the extent to which altered loading in the temporomandibular joint (TMJ), as might be associated with a malocclusion, drives degeneration of articulating surfaces in the TMJ. We therefore sought to quantify the effects of altered joint loading on the mechanical properties and biochemical content and distribution of TMJ fibrocartilage in the rabbit. DESIGN Altered TMJ loading was induced with a 1mm splint placed unilaterally over the maxillary and mandibular molars for 6 weeks. At that time, TMJ fibrocartilage was assessed by compression testing, biochemical content (collagen, glycosaminoglycan (GAG), DNA) and distribution (histology), for both the TMJ disc and the condylar fibrocartilage. RESULTS There were no changes in the TMJ disc for any of the parameters tested. The condylar fibrocartilage from the splinted animals was significantly stiffer and the DNA content was significantly lower than that in control animals. There was significant remodeling in the condylar fibrocartilage layers as manifested by a change in GAG and collagen II distribution and a loss of defined cell layers. CONCLUSIONS A connection between the compressive properties of TMJ condylar fibrocartilage after 6 weeks of splinting and the changes in histology was observed. These results suggest a change in joint loading leads to condylar damage, which may contribute to pain associated with at least some forms of TMJ disease.
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Affiliation(s)
- Sarah E Henderson
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jesse R Lowe
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mauro A Tudares
- Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael S Gold
- Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alejandro J Almarza
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Oral Biology, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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Shibazaki-Yorozuya R, Yamada A, Nagata S, Ueda K, Miller AJ, Maki K. Three-dimensional longitudinal changes in craniofacial growth in untreated hemifacial microsomia patients with cone-beam computed tomography. Am J Orthod Dentofacial Orthop 2014; 145:579-94. [PMID: 24785922 DOI: 10.1016/j.ajodo.2013.09.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 09/01/2013] [Accepted: 09/01/2013] [Indexed: 10/25/2022]
Abstract
INTRODUCTION The purpose of this study was to evaluate the concept that the affected and contralateral sides do not grow at the same rate in patients with hemifacial microsomia. Changes in the cranial base, maxilla, mandible, and occlusal plane were evaluated on 3-dimensional images from cone-beam computed tomography data in untreated patients. METHODS Six patients were classified as having mandibular Pruzansky/Kaban type I, IIA, or IIB hemifacial microsomia. Cone-beam computed tomography (MercuRay; Hitachi, Tokyo, Japan) scans were taken before orthodontic treatment during both growth and postpuberty periods. RESULTS The cranial base as defined by the position of the mastoid process was in a different position between the affected and contralateral control sides. The nasomaxillary length or height was shorter on the affected side for all 6 patients with hemifacial microsomia regardless of its severity, and it grew less than on the contralateral control side in 5 of the 6 patients. The occlusal plane angle became more inclined in 4 of the 6 patients. The mandibular ramus was shorter on the affected side in all patients and grew less on the affected side in 5 of the 6 patients. The mandibular body grew slower, the same, or faster than on the control side. CONCLUSIONS The cranial base, position of the condyle, lengths of the condyle and ramus, and positions of the gonial angle and condyle can vary between the affected and contralateral control sides of patients with hemifacial microsomia, with the ramus and nasomaxillary length usually growing slower than they grow on the control side. These results suggest that many factors affect the growth rate of the craniofacial region and, specifically, the mandible in patients with hemifacial microsomia.
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Affiliation(s)
- Reiko Shibazaki-Yorozuya
- Assistant professor, Department of Orthodontics, School of Dentistry, Showa University, Tokyo, Japan.
| | - Akira Yamada
- Lecturer, Department of Plastic and Reconstructive Surgery, Osaka Medical School, Osaka, Japan; visiting professor, World Craniofacial Foundation, Dallas, Tex
| | - Satoru Nagata
- Director, Nagata Microtia and Reconstructive Plastic Surgery Clinic, Saitama, Japan; visiting professor, Department of Plastic and Reconstructive Surgery, University of California Irvine School of Medicine, Irvine, Calif
| | - Kouichi Ueda
- Professor and chair, Department of Plastic and Reconstructive Surgery, Osaka Medical School, Osaka, Japan
| | - Arthur J Miller
- Professor, Division of Orthodontics, Department of Orofacial Sciences, School of Dentistry, University of California, San Francisco, Calif
| | - Koutaro Maki
- Professor and chair, Department of Orthodontics, School of Dentistry, Showa University, Tokyo, Japan
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Nakamura A, Zeredo JL, Utsumi D, Fujishita A, Koga Y, Yoshida N. Influence of malocclusion on the development of masticatory function and mandibular growth. Angle Orthod 2013; 83:749-57. [PMID: 23327417 DOI: 10.2319/083012-698.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE To verify the hypothesis that appropriate acquisition of masticatory function and normal growth of the mandible are modified by malocclusion. MATERIALS AND METHODS Eighteen Jcl:ICR mice were divided into two groups. In one group we shifted the mandible laterally using an occlusal guidance appliance, creating a posterior crossbite at 5 weeks of age. The other group served as control. After 10 weeks, three-dimensional jaw movements and muscle activities were recorded simultaneously during mastication. Microcomputed tomography scans were obtained in vivo to evaluate morphometric changes in the mandible. RESULTS (1) The jaw movement pattern in the sagittal plane showed significantly less anteroposterior excursion in the malocclusion group during the late-closing phase (power phase). (2) Electromyography showed significantly less masseter activity in the malocclusion group. (3) The condylar width and mandibular bone mineral density (BMD) were significantly reduced in the malocclusion mice compared to the normal mice. CONCLUSIONS These findings suggest that optimization of the chewing pattern and acquisition of appropriate masticatory function is impeded by malocclusion. Altered mechanical loading to the mandible may cause significant reduction of condylar width and mandibular BMD.
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Affiliation(s)
- Aya Nakamura
- Department of Orthodontics and Dentofacial Orthopedics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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Tecco S, Saccucci M, Nucera R, Polimeni A, Pagnoni M, Cordasco G, Festa F, Iannetti G. Condylar volume and surface in Caucasian young adult subjects. BMC Med Imaging 2010; 10:28. [PMID: 21194477 PMCID: PMC3019198 DOI: 10.1186/1471-2342-10-28] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 12/31/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There have been no quantitative standards for volumetric and surface measurements of the mandibular condyle in Caucasian population. However, the recently developed cone-beam computed tomography (CBCT) system allows measurement of these parameters with high accuracy. METHODS CBCT was used to measure the condylar volume, surface and the volume to surface ratio, called the Morphometric Index (MI), of 300 temporo-mandibular joints (TMJ) in 150 Caucasian young adult subjects, with varied malocclusions, without pain or dysfunction of TMJs. RESULTS The condylar volume was 691.26 ± 54.52 mm3 in males and 669.65 ± 58.80 mm3 in, and was significantly higher (p< 0.001) in the males. The same was observed for the condylar surface, although without statistical significance (406.02 ± 55.22 mm2 in males and 394.77 ± 60.73 mm2 in females).Furthermore, the condylar volume (693.61 ± 62.82 mm3 ) in the right TMJ was significantly higher than in the left (666.99 ± 48.67 mm3, p < 0.001) as was the condylar surface (411.24 ± 57.99 mm2 in the right TMJ and 389.41 ± 56.63 mm2 in the left TMJ; t = 3.29; p < 0.01). The MI is 1.72 ± 0.17 for the whole sample, with no significant difference between males and females or the right and left sides. CONCLUSION These data from temporomandibular joints of patients without pain or clinical dysfunction might serve as examples of normal TMJ's in the general population not seeking orthodontic care.
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Affiliation(s)
- Simona Tecco
- Department of Oral Science, Nano and Biotechnology, University G,D'Annunzio, Via dei Vestini 31, Chieti, 66013, Italy.
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Abbassy MA, Watari I, Soma K. The effect of diabetes mellitus on rat mandibular bone formation and microarchitecture. Eur J Oral Sci 2010; 118:364-9. [DOI: 10.1111/j.1600-0722.2010.00739.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Tsai CY, Huang RY, Lee CM, Hsiao WT, Yang LY. Morphologic and bony structural changes in the mandible after a unilateral injection of botulinum neurotoxin in adult rats. J Oral Maxillofac Surg 2010; 68:1081-7. [PMID: 20189701 DOI: 10.1016/j.joms.2009.12.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 12/07/2009] [Accepted: 12/21/2009] [Indexed: 11/18/2022]
Abstract
PURPOSE Previous animal experiments showed how reduced masticatory function plays an important role in the craniofacial and mandibular regions in the growing period. However, articles focusing on the effects of reduced masticatory function in adult animals are quite scarce. The purpose of this study was to evaluate the effects of reduced masticatory muscle activity on the jaw bones of adult rats. MATERIALS AND METHODS Botulinum neurotoxin type A (BTX-A) was injected into the left masseter muscle to reduce masticatory muscle function, and sequential changes in the jaw bones were investigated. Ten male 60-day-old Sprague-Dawley rats with a mean body weight of about 300 g were used. The following procedures were performed on each sample: 25 U/mL (0.3 mL) of BTX-A was injected into the left masseter muscle, whereas the right masseter muscle received an equal amount of sterilized saline solution. Ninety days after the procedure, the rats were sacrificed, and the weights of the masseter muscles were recorded. Meanwhile, direct anthropometric measurements were taken, and the cortical thickness, trabecular thickness, and bone mineral content of the skull and mandible were measured. All measurements were evaluated with statistical software. RESULTS There were significant differences in all measurements on the BTX-A side compared with those on the control side. The differences included a decreased ramus height, increased gonial angle, and increased crown height of the posterior teeth on the injection side. Significant decreases in the muscle weight, bone mineral content, cortical thickness, and trabecular thickness were also seen on the paralyzed side compared with the non-injection side. CONCLUSIONS We found that reduced masticatory function in adult rats affected the weight of the masseter muscle and the bony structure and dentition.
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Affiliation(s)
- Chi-Yang Tsai
- Department of Orthodontics, Graduate Institute of Dentistry, College of Oral Medicine, Taipei Medical University and Hospital, Taipei, Taiwan.
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Age- and sex-related changes of mandibular condylar cartilage and subchondral bone: A histomorphometric and micro-CT study in rats. Arch Oral Biol 2010; 55:155-63. [DOI: 10.1016/j.archoralbio.2009.11.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 11/26/2009] [Accepted: 11/26/2009] [Indexed: 11/21/2022]
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Influence of extraoral lateral force loading on the mandible in the mandibular development of growing rats. Am J Orthod Dentofacial Orthop 2008; 134:782-91. [DOI: 10.1016/j.ajodo.2006.10.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2006] [Revised: 10/01/2006] [Accepted: 10/01/2006] [Indexed: 11/20/2022]
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Watanabe A, Yamaguchi M, Utsunomiya T, Yamamoto H, Kasai K. Histopathological changes in collagen and matrix metalloproteinase levels in articular condyle of experimental model rats with jaw deformity. Orthod Craniofac Res 2008; 11:105-18. [DOI: 10.1111/j.1601-6343.2008.00420.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Liu C, Kaneko S, Soma K. Expression of integrinalpha5beta1, focal adhesion kinase and integrin-linked kinase in rat condylar cartilage during mandibular lateral displacement. Arch Oral Biol 2008; 53:701-8. [PMID: 18359002 DOI: 10.1016/j.archoralbio.2008.02.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Revised: 11/06/2007] [Accepted: 02/01/2008] [Indexed: 11/16/2022]
Abstract
Integrins are cell-surface mechanochemical sensors and transducers involved in various cellular processes in combination with extracellular ligands. The aim of this study was to investigate the effect of mechanical stress on the expression of integrinalpha5beta1 and its downstream kinases, focal adhesion kinase (FAK) and integrin-linked kinase (ILK), in condylar cartilage during mandible lateral shift in young rats. Sixty 4-week-old male Wistar rats were divided at random into five control groups and five experimental groups. All rats in the experimental groups were fitted with a resin plate to functionally displace the mandible 2mm to the left (ipsilateral side). The rats were killed 1, 3, 7, 14 and 28 days after attachment of the appliance. Serial 6-mum sagittal sections were cut through the condylar head and processed for immunostaining of integrinalpha5beta1, FAK and ILK. The results were quantified using an image analysing system. Integrinalpha5beta1 expression in the superior-posterior region of the condylar cartilage on the ipsilateral side increased from 3 to 14 days compared with the contralateral side, with an intermediate level of expression in the control groups. Expression of FAK and ILK was similar to integrinalpha5beta1 expression, and they were also upregulated on the ipsilateral side compared with the contralateral side at the early stages of the experiment. The different mechanical loading on the two sides of the condylar cartilage led to different expression patterns of integrinalpha5beta1, FAK and ILK, which may correlate with the different morphological and histological changes seen between sides during mandibular lateral shift.
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Affiliation(s)
- Chang Liu
- Hospital for Stomatology, JiLin University, Changchun, JiLin Province, China.
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Kwon TG, Park HS, Lee SH, Park IS, An CH. Influence of unilateral masseter muscle atrophy on craniofacial morphology in growing rabbits. J Oral Maxillofac Surg 2007; 65:1530-7. [PMID: 17656279 DOI: 10.1016/j.joms.2006.10.059] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 06/14/2006] [Accepted: 10/26/2006] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of the study was to evaluate whether the induction of unilateral masticatory muscle dysfunction can alter the skeletal growth patterns. MATERIALS AND METHODS Twenty-one white male New Zealand rabbits (4 weeks old) were divided into 3 groups of 7 subjects: group 1 served as the control to study normal craniofacial growth. In groups 2 and 3, rabbits were injected with 5 units and 15 units of Botulinum toxin A (BTXA) into the right masseter muscle, respectively. The effect of a neuromuscular blockade of masseteric activity on craniofacial growth was evaluated with 3 samples of serial computed tomography (CT) scans with a slice thickness of 0.625 mm, taken at 4 weeks (base line), 8 weeks (endpoint of prepubertal craniofacial growth), and 24 weeks (after pubertal growth). RESULTS The ipsilateral mandibular ramus height, zygomatic arch length, and masseteric length did not develop as much as those of the contralateral side after pubertal growth. At age 24 weeks, the masseter muscle volume asymmetry index reached -13.8% (group 2), -18.4% (group 3), and -1.6% for the control group. The ipsilateral side of the hemimandible showed less bone volume after 8 weeks but it showed partially recovered symmetry at 24 weeks. The maxillomandibular incisor midline and transverse molar discrepancies were not evident in any of the groups. CONCLUSIONS The BTXA injection can be an effective method in inducing site-specific muscular hypofunctions so that masticatory muscle-craniofacial bone interaction can be investigated efficiently. The result showed that the unilateral atrophy of the masseter muscle in the growing subjects influenced the morphology of the local skeletal sites. This did not, however, result ultimately in mandibular midline asymmetry or right-left asymmetry in hemimandibular volume after growth. The results imply that alterations in specific masticatory muscle function can be compensated by the growth of other structural components.
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Affiliation(s)
- Tae-Geon Kwon
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Kyungpook National University, Daegu, Korea.
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Liu C, Kaneko S, Soma K. Effects of a Mandibular Lateral Shift on the Condyle and Mandibular Bone in Growing Rats. Angle Orthod 2007; 77:787-93. [PMID: 17685779 DOI: 10.2319/091806-377] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Accepted: 11/01/2006] [Indexed: 11/23/2022] Open
Abstract
Abstract
Objective: To examine the effects of mandibular lateral shift on the growth and morphology of the condyle and mandibular bone in growing rats.
Materials and Methods: A maxillary resin plate was designed to displace 4-week-old rat mandibles 2 mm to the left during closure. The plate was cemented, and the rats were killed after 2, 4, 8, or 12 weeks. Gross dimensions of the condylar head were measured. Radiographic films of the mandibles were exposed, and selected measurements were made. The newly formed bone in the condyle was evaluated with periodic acid and Schiff's reagent (PAS) staining.
Results: The length of the condylar head was greater on the ipsilateral side compared with the contralateral side. The experimental rats developed an asymmetric mandible, shorter in horizontal dimension but longer in the vertical dimension on the ipsilateral side. The mandibular growth direction was also affected, with the mandible on the ipsilateral side growing in a more anterior and superior direction. The amount of newly formed bone was greater in the superior subchondral region but lower in the posterior subchondral region on the ipsilateral side compared with the contralateral side.
Conclusions: Mechanical stimuli delivered by a functional shift produce a series of morphological and histological responses in the condyle and lead to condylar and mandibular asymmetry in rats.
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Affiliation(s)
- Chang Liu
- Department of Orofacial Development and Function, Graduate School, Tokyo Medical and Dental University, Japan.
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Kokai S, Yabushita T, Zeredo JL, Toda K, Soma K. Functional Changes of the Temporomandibular Joint Mechanoreceptors Induced by a Lateral Mandibular Shift in Rats. Angle Orthod 2007; 77:436-41. [PMID: 17465650 DOI: 10.2319/0003-3219(2007)077[0436:fcottj]2.0.co;2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Accepted: 07/01/2006] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE To investigate changes in functional characteristics of the temporomandibular joint (TMJ) mechanoreceptors under mandibular lateral shift. MATERIALS AND METHODS Forty 7-week-old male Wistar rats were divided into control and experimental groups. Rats in the experimental group received a modified guiding appliance (MGA) that was designed to shift the mandible to the left side in the occlusal position. Single-unit activities of the TMJ mechanoreceptors were evoked by indirect stimulation of passive jaw movement. Electrophysiologic recordings of TMJ units were obtained 1, 3, 5, 7, and 9 weeks after MGA setting from the gasserian ganglion. RESULTS At 1 week after mandibular shift, the firing thresholds were the lowest and the maximum instantaneous frequencies were the highest in TMJ units. At 5 weeks, the firing thresholds in the nonshifted side were significantly lower than those in the shifted side. The maximum instantaneous frequencies in the nonshifted side were significantly higher than those in the shifted side at 1, 5, and 7 weeks. CONCLUSION These results suggest that the functional lateral shift of the mandible could alter the response properties of TMJ mechanoreceptors, particularly on the nonshifted side.
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Affiliation(s)
- Satoshi Kokai
- Dr Satoshi Kokai, Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8549, Tokyo, Japan.
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Kwon TG. Influence of Unilateral Masticatory Muscle Atrophy on Craniofacial Morphology in Growing Rabbit. J Oral Maxillofac Surg 2005. [DOI: 10.1016/j.joms.2005.05.278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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